diff --git a/.dockerignore b/.dockerignore
index 65e3ba2ed..5a71055bc 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -1 +1,3 @@
 test/
+bin/cql*
+*.cover.out
diff --git a/.gitignore b/.gitignore
index 0ce9eb7e2..4ae821fc2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,6 @@
 *.trace
+conf*
+..bfg-report
 pprof.txt
 .dsn
 *.svg
@@ -13,9 +15,11 @@ vendor/**/.gitignore
 node_*/
 kayak_test
 *.conf
+*.ldb
 *.db
 *.db-shm
 *.db-wal
+*.ldb
 .DS_Store
 msgpack-20180824
 
diff --git a/.travis.yml b/.travis.yml
index f4644b655..93a905397 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,7 @@ env:
     - REVIEWDOG_VERSION=0.9.11
 language: go
 go:
-  - '1.11.x'
+  - '1.10.x'
 
 os:
   - linux
@@ -32,7 +32,9 @@ script:
   - bash build.sh
   - go test -v -race -failfast -parallel 16 -cpu 16 $(go list ./... | grep -v "/vendor/") -coverprofile cover.out
   - cd rpc && go test -test.bench ^BenchmarkPersistentCaller_Call$ -test.run ^$ && cd -
-  - gocovmerge cover.out $(find cmd -name "*.cover.out") > coverage.txt && rm -f cover.out
+  - bash cleanupDB.sh || true
+  - cd cmd/cql-minerd && go test -bench=^BenchmarkMinerTwo$ -benchtime=5s -run ^$ && cd -
+  - gocovmerge cover.out $(find cmd -name "*.cover.out") | grep -F -v '_gen.go' > coverage.txt && rm -f cover.out
   - bash <(curl -s https://codecov.io/bash)
   - >-
     golint ./... | grep -v 'vendor/' | grep -v 'server/' | grep -v 'utils/' | reviewdog -f=golint -reporter=github-pr-review || true
diff --git a/CHANGELOG.md b/CHANGELOG.md
index bcca8da03..37674d155 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,24 @@
 # Changelog
 
+## [v0.0.4](https://github.com/CovenantSQL/CovenantSQL/tree/v0.0.4) (2018-11-08)
+
+[Full Changelog](https://github.com/CovenantSQL/CovenantSQL/compare/v0.0.3...v0.0.4)
+
+**Fixed bugs:**
+
+- Potential deadlock in testing [\#93](https://github.com/CovenantSQL/CovenantSQL/issues/93)
+
+**Closed issues:**
+
+- Where can I find covenantsql.io/covenantsql\_adapter [\#53](https://github.com/CovenantSQL/CovenantSQL/issues/53)
+
+**Merged pull requests:**
+
+- Fix loadChain failure, remove the lock in sync\(\) [\#114](https://github.com/CovenantSQL/CovenantSQL/pull/114) ([zeqing-guo](https://github.com/zeqing-guo))
+- Kayak performance improvement refactor [\#112](https://github.com/CovenantSQL/CovenantSQL/pull/112) ([xq262144](https://github.com/xq262144))
+- Fix index out of bound, refactor part of sqlchain code [\#110](https://github.com/CovenantSQL/CovenantSQL/pull/110) ([leventeliu](https://github.com/leventeliu))
+- Support lastInsertID/affectedRows in kayak [\#109](https://github.com/CovenantSQL/CovenantSQL/pull/109) ([xq262144](https://github.com/xq262144))
+
 ## [v0.0.3](https://github.com/CovenantSQL/CovenantSQL/tree/v0.0.3) (2018-11-04)
 
 [Full Changelog](https://github.com/CovenantSQL/CovenantSQL/compare/v0.0.2...v0.0.3)
@@ -7,7 +26,6 @@
 **Fixed bugs:**
 
 - Cannot receive tokens from testnet [\#84](https://github.com/CovenantSQL/CovenantSQL/issues/84)
-- Potential deadlock in testing [\#93](https://github.com/CovenantSQL/CovenantSQL/issues/93)
 
 **Closed issues:**
 
@@ -49,27 +67,6 @@
 
 [Full Changelog](https://github.com/CovenantSQL/CovenantSQL/compare/82811a8fcac65d74aefbb506450e4477ecdad048...v0.0.1)
 
-**TestNet**
- 
-1. Ready for CLI or SDK usage. For now, Linux & OSX supported only.
-1. SQL Chain Explorer is ready.
-
-**TestNet Known Issues**
-
-1. Main Chain
-   1. Allocation algorithm for BlockProducer and Miner is incomplete.
-   1. Joining as BP or Miner is unsupported for now. _Fix@2018-10-12_
-   1. Forking Recovery algorithm is incomplete.
-1. Connector
-   1. [Java](https://github.com/CovenantSQL/covenant-connector) and [Golang Connector](https://github.com/CovenantSQL/CovenantSQL/tree/develop/client) is ready.
-   1. ĐApp support for ETH or EOS is incomplete. 
-   1. Java connector protocol is based on RESTful HTTPS, change to Golang DH-RPC latter.
-1. Database
-   1. Cartesian product or big join caused OOM. _Fix@2018-10-12_
-   1. SQL Query filter is incomplete. _Fix@2018-10-12_
-   1. Forking Recovery algorithm is incomplete.
-   1. Database for TestNet is World Open on [Explorer](https://explorer.dbhub.org).
-
 **Closed issues:**
 
 - ThunderDB has been renamed to CovenantSQL [\#58](https://github.com/CovenantSQL/CovenantSQL/issues/58)
diff --git a/Gopkg.lock b/Gopkg.lock
index 1cee45a5b..dca93369b 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -1,6 +1,19 @@
 # This file is autogenerated, do not edit; changes may be undone by the next 'dep ensure'.
 
 
+[[projects]]
+  branch = "master"
+  digest = "1:2fab77e19256b26d733b70e1f68cd965cb87e38e3a619fa960cf319aef743d53"
+  name = "bazil.org/fuse"
+  packages = [
+    ".",
+    "fs",
+    "fs/fstestutil",
+    "fuseutil",
+  ]
+  pruneopts = "UT"
+  revision = "65cc252bf6691cb3c7014bcb2c8dc29de91e3a7e"
+
 [[projects]]
   branch = "master"
   digest = "1:341f9de25b320f45124840fa084aa804a6659cfeae2ea93a45424fd73f9d7da5"
@@ -575,10 +588,11 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:eceec1bdeb912f2aed8e5e9c8c81927649925095e1e4d5b85b331898fee06397"
+  digest = "1:67ee3460c086005f76f49c4d5f38a80ce11d68986de22979c75bf04e8372db9c"
   name = "golang.org/x/net"
   packages = [
     "bpf",
+    "context",
     "html",
     "html/atom",
     "internal/iana",
@@ -612,6 +626,9 @@
   analyzer-name = "dep"
   analyzer-version = 1
   input-imports = [
+    "bazil.org/fuse",
+    "bazil.org/fuse/fs",
+    "bazil.org/fuse/fs/fstestutil",
     "github.com/CovenantSQL/HashStablePack/marshalhash",
     "github.com/CovenantSQL/go-sqlite3-encrypt",
     "github.com/CovenantSQL/sqlparser",
diff --git a/bin/docker-entry.sh b/bin/docker-entry.sh
index 23104a50e..45b813e19 100755
--- a/bin/docker-entry.sh
+++ b/bin/docker-entry.sh
@@ -4,11 +4,11 @@ echo nameserver 1.1.1.1 > /etc/resolv.conf
 
 case "${COVENANT_ROLE}" in
 miner)
-    exec /app/cql-minerd -config "${COVENANT_CONF}"
+    exec /app/cql-minerd -config "${COVENANT_CONF}" "${@}"
     ;;
 blockproducer)
     rm -f /app/node_*/chain.db
-    exec /app/cqld -config "${COVENANT_CONF}"
+    exec /app/cqld -config "${COVENANT_CONF}" "${@}"
     ;;
 observer)
     rm -f /app/node_observer/observer.db
diff --git a/blockproducer/chain.go b/blockproducer/chain.go
index f91da6f92..bcb00161b 100644
--- a/blockproducer/chain.go
+++ b/blockproducer/chain.go
@@ -35,6 +35,7 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
 	"github.com/coreos/bbolt"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -56,10 +57,9 @@ type Chain struct {
 	rt *rt
 	cl *rpc.Caller
 
-	blocksFromSelf chan *pt.Block
-	blocksFromRPC  chan *pt.Block
-	pendingTxs     chan pi.Transaction
-	stopCh         chan struct{}
+	blocksFromRPC chan *pt.Block
+	pendingTxs    chan pi.Transaction
+	stopCh        chan struct{}
 }
 
 // NewChain creates a new blockchain.
@@ -121,15 +121,14 @@ func NewChain(cfg *Config) (*Chain, error) {
 
 	// create chain
 	chain := &Chain{
-		db:             db,
-		ms:             newMetaState(),
-		bi:             newBlockIndex(),
-		rt:             newRuntime(cfg, accountAddress),
-		cl:             rpc.NewCaller(),
-		blocksFromSelf: make(chan *pt.Block),
-		blocksFromRPC:  make(chan *pt.Block),
-		pendingTxs:     make(chan pi.Transaction),
-		stopCh:         make(chan struct{}),
+		db:            db,
+		ms:            newMetaState(),
+		bi:            newBlockIndex(),
+		rt:            newRuntime(cfg, accountAddress),
+		cl:            rpc.NewCaller(),
+		blocksFromRPC: make(chan *pt.Block),
+		pendingTxs:    make(chan pi.Transaction),
+		stopCh:        make(chan struct{}),
 	}
 
 	log.WithField("genesis", cfg.Genesis).Debug("pushing genesis block")
@@ -168,15 +167,14 @@ func LoadChain(cfg *Config) (chain *Chain, err error) {
 	}
 
 	chain = &Chain{
-		db:             db,
-		ms:             newMetaState(),
-		bi:             newBlockIndex(),
-		rt:             newRuntime(cfg, accountAddress),
-		cl:             rpc.NewCaller(),
-		blocksFromSelf: make(chan *pt.Block),
-		blocksFromRPC:  make(chan *pt.Block),
-		pendingTxs:     make(chan pi.Transaction),
-		stopCh:         make(chan struct{}),
+		db:            db,
+		ms:            newMetaState(),
+		bi:            newBlockIndex(),
+		rt:            newRuntime(cfg, accountAddress),
+		cl:            rpc.NewCaller(),
+		blocksFromRPC: make(chan *pt.Block),
+		pendingTxs:    make(chan pi.Transaction),
+		stopCh:        make(chan struct{}),
 	}
 
 	err = chain.db.View(func(tx *bolt.Tx) (err error) {
@@ -332,6 +330,7 @@ func (c *Chain) pushGenesisBlock(b *pt.Block) (err error) {
 func (c *Chain) pushBlock(b *pt.Block) error {
 	err := c.checkBlock(b)
 	if err != nil {
+		err = errors.Wrap(err, "check block failed")
 		return err
 	}
 
@@ -608,14 +607,6 @@ func (c *Chain) processBlocks() {
 	var stash []*pt.Block
 	for {
 		select {
-		case block := <-c.blocksFromSelf:
-			h := c.rt.getHeightFromTime(block.Timestamp())
-			if h == c.rt.getNextTurn()-1 {
-				err := c.pushBlockWithoutCheck(block)
-				if err != nil {
-					log.Error(err)
-				}
-			}
 		case block := <-c.blocksFromRPC:
 			if h := c.rt.getHeightFromTime(block.Timestamp()); h > c.rt.getNextTurn()-1 {
 				// Stash newer blocks for later check
@@ -630,7 +621,11 @@ func (c *Chain) processBlocks() {
 				} else {
 					err := c.pushBlock(block)
 					if err != nil {
-						log.Error(err)
+						log.WithFields(log.Fields{
+							"block_hash":        block.BlockHash(),
+							"block_parent_hash": block.ParentHash(),
+							"block_timestamp":   block.Timestamp(),
+						}).Debug(err)
 					}
 				}
 
@@ -662,7 +657,7 @@ func (c *Chain) processTxs() {
 					"next_turn":   c.rt.getNextTurn(),
 					"head_height": c.rt.getHead().Height,
 					"head_block":  c.rt.getHead().Head.String(),
-					"transaction": tx.GetHash().String(),
+					"transaction": tx.Hash().String(),
 				}).Debugf("Failed to push tx with error: %v", err)
 			}
 		case <-c.stopCh:
diff --git a/blockproducer/chain_test.go b/blockproducer/chain_test.go
index 2955ad2df..1da9c742f 100644
--- a/blockproducer/chain_test.go
+++ b/blockproducer/chain_test.go
@@ -29,7 +29,7 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/pow/cpuminer"
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
 	. "github.com/smartystreets/goconvey/convey"
 )
@@ -279,13 +279,13 @@ func TestMultiNode(t *testing.T) {
 							br, err := generateRandomBillingRequest()
 							c.So(err, ShouldBeNil)
 
-							bReq := &ct.AdviseBillingReq{
+							bReq := &types.AdviseBillingReq{
 								Envelope: proto.Envelope{
 									// TODO(lambda): Add fields.
 								},
 								Req: br,
 							}
-							bResp := &ct.AdviseBillingResp{}
+							bResp := &types.AdviseBillingResp{}
 							log.WithFields(log.Fields{
 								"node":        val,
 								"requestHash": br.RequestHash,
diff --git a/blockproducer/db_service.go b/blockproducer/db_service.go
index 8deea1e03..463d925c8 100644
--- a/blockproducer/db_service.go
+++ b/blockproducer/db_service.go
@@ -30,9 +30,8 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 	dto "github.com/prometheus/client_model/go"
 )
 
@@ -66,7 +65,7 @@ type DBService struct {
 }
 
 // CreateDatabase defines block producer create database logic.
-func (s *DBService) CreateDatabase(req *CreateDatabaseRequest, resp *CreateDatabaseResponse) (err error) {
+func (s *DBService) CreateDatabase(req *types.CreateDatabaseRequest, resp *types.CreateDatabaseResponse) (err error) {
 	// verify signature
 	if err = req.Verify(); err != nil {
 		return
@@ -99,7 +98,7 @@ func (s *DBService) CreateDatabase(req *CreateDatabaseRequest, resp *CreateDatab
 	log.WithField("peers", peers).Debug("generated peers info")
 
 	// TODO(lambda): call accounting features, top up deposit
-	var genesisBlock *ct.Block
+	var genesisBlock *types.Block
 	if genesisBlock, err = s.generateGenesisBlock(dbID, req.Header.ResourceMeta); err != nil {
 		return
 	}
@@ -118,9 +117,9 @@ func (s *DBService) CreateDatabase(req *CreateDatabaseRequest, resp *CreateDatab
 		return
 	}
 
-	initSvcReq := new(wt.UpdateService)
-	initSvcReq.Header.Op = wt.CreateDB
-	initSvcReq.Header.Instance = wt.ServiceInstance{
+	initSvcReq := new(types.UpdateService)
+	initSvcReq.Header.Op = types.CreateDB
+	initSvcReq.Header.Instance = types.ServiceInstance{
 		DatabaseID:   dbID,
 		Peers:        peers,
 		GenesisBlock: genesisBlock,
@@ -129,9 +128,9 @@ func (s *DBService) CreateDatabase(req *CreateDatabaseRequest, resp *CreateDatab
 		return
 	}
 
-	rollbackReq := new(wt.UpdateService)
-	rollbackReq.Header.Op = wt.DropDB
-	rollbackReq.Header.Instance = wt.ServiceInstance{
+	rollbackReq := new(types.UpdateService)
+	rollbackReq.Header.Op = types.DropDB
+	rollbackReq.Header.Instance = types.ServiceInstance{
 		DatabaseID: dbID,
 	}
 	if err = rollbackReq.Sign(privateKey); err != nil {
@@ -143,7 +142,7 @@ func (s *DBService) CreateDatabase(req *CreateDatabaseRequest, resp *CreateDatab
 	}
 
 	// save to meta
-	instanceMeta := wt.ServiceInstance{
+	instanceMeta := types.ServiceInstance{
 		DatabaseID:   dbID,
 		Peers:        peers,
 		ResourceMeta: req.Header.ResourceMeta,
@@ -168,7 +167,7 @@ func (s *DBService) CreateDatabase(req *CreateDatabaseRequest, resp *CreateDatab
 }
 
 // DropDatabase defines block producer drop database logic.
-func (s *DBService) DropDatabase(req *DropDatabaseRequest, resp *DropDatabaseResponse) (err error) {
+func (s *DBService) DropDatabase(req *types.DropDatabaseRequest, resp *types.DropDatabaseResponse) (err error) {
 	// verify signature
 	if err = req.Verify(); err != nil {
 		return
@@ -185,15 +184,15 @@ func (s *DBService) DropDatabase(req *DropDatabaseRequest, resp *DropDatabaseRes
 	}()
 
 	// get database peers
-	var instanceMeta wt.ServiceInstance
+	var instanceMeta types.ServiceInstance
 	if instanceMeta, err = s.ServiceMap.Get(req.Header.DatabaseID); err != nil {
 		return
 	}
 
 	// call miner nodes to drop database
-	dropDBSvcReq := new(wt.UpdateService)
-	dropDBSvcReq.Header.Op = wt.DropDB
-	dropDBSvcReq.Header.Instance = wt.ServiceInstance{
+	dropDBSvcReq := new(types.UpdateService)
+	dropDBSvcReq.Header.Op = types.DropDB
+	dropDBSvcReq.Header.Instance = types.ServiceInstance{
 		DatabaseID: req.Header.DatabaseID,
 	}
 	if dropDBSvcReq.Header.Signee, err = kms.GetLocalPublicKey(); err != nil {
@@ -228,7 +227,7 @@ func (s *DBService) DropDatabase(req *DropDatabaseRequest, resp *DropDatabaseRes
 }
 
 // GetDatabase defines block producer get database logic.
-func (s *DBService) GetDatabase(req *GetDatabaseRequest, resp *GetDatabaseResponse) (err error) {
+func (s *DBService) GetDatabase(req *types.GetDatabaseRequest, resp *types.GetDatabaseResponse) (err error) {
 	// verify signature
 	if err = req.Verify(); err != nil {
 		return
@@ -245,7 +244,7 @@ func (s *DBService) GetDatabase(req *GetDatabaseRequest, resp *GetDatabaseRespon
 	}()
 
 	// fetch from meta
-	var instanceMeta wt.ServiceInstance
+	var instanceMeta types.ServiceInstance
 	if instanceMeta, err = s.ServiceMap.Get(req.Header.DatabaseID); err != nil {
 		return
 	}
@@ -268,9 +267,9 @@ func (s *DBService) GetDatabase(req *GetDatabaseRequest, resp *GetDatabaseRespon
 }
 
 // GetNodeDatabases defines block producer get node databases logic.
-func (s *DBService) GetNodeDatabases(req *wt.InitService, resp *wt.InitServiceResponse) (err error) {
+func (s *DBService) GetNodeDatabases(req *types.InitService, resp *types.InitServiceResponse) (err error) {
 	// fetch from meta
-	var instances []wt.ServiceInstance
+	var instances []types.ServiceInstance
 	if instances, err = s.ServiceMap.GetDatabases(req.GetNodeID().ToNodeID()); err != nil {
 		return
 	}
@@ -323,7 +322,7 @@ func (s *DBService) generateDatabaseID(reqNodeID *proto.RawNodeID) (dbID proto.D
 	}
 }
 
-func (s *DBService) allocateNodes(lastTerm uint64, dbID proto.DatabaseID, resourceMeta wt.ResourceMeta) (peers *proto.Peers, err error) {
+func (s *DBService) allocateNodes(lastTerm uint64, dbID proto.DatabaseID, resourceMeta types.ResourceMeta) (peers *proto.Peers, err error) {
 	curRange := int(resourceMeta.Node)
 	excludeNodes := make(map[proto.NodeID]bool)
 	var allocated []allocatedNode
@@ -506,7 +505,7 @@ func (s *DBService) buildPeers(term uint64, allocated []proto.NodeID) (peers *pr
 	return
 }
 
-func (s *DBService) generateGenesisBlock(dbID proto.DatabaseID, resourceMeta wt.ResourceMeta) (genesisBlock *ct.Block, err error) {
+func (s *DBService) generateGenesisBlock(dbID proto.DatabaseID, resourceMeta types.ResourceMeta) (genesisBlock *types.Block, err error) {
 	// TODO(xq262144): following is stub code, real logic should be implemented in the future
 	emptyHash := hash.Hash{}
 
@@ -519,9 +518,9 @@ func (s *DBService) generateGenesisBlock(dbID proto.DatabaseID, resourceMeta wt.
 		return
 	}
 
-	genesisBlock = &ct.Block{
-		SignedHeader: ct.SignedHeader{
-			Header: ct.Header{
+	genesisBlock = &types.Block{
+		SignedHeader: types.SignedHeader{
+			Header: types.Header{
 				Version:     0x01000000,
 				Producer:    nodeID,
 				GenesisHash: emptyHash,
@@ -535,7 +534,7 @@ func (s *DBService) generateGenesisBlock(dbID proto.DatabaseID, resourceMeta wt.
 	return
 }
 
-func (s *DBService) batchSendSvcReq(req *wt.UpdateService, rollbackReq *wt.UpdateService, nodes []proto.NodeID) (err error) {
+func (s *DBService) batchSendSvcReq(req *types.UpdateService, rollbackReq *types.UpdateService, nodes []proto.NodeID) (err error) {
 	if err = s.batchSendSingleSvcReq(req, nodes); err != nil {
 		s.batchSendSingleSvcReq(rollbackReq, nodes)
 	}
@@ -543,7 +542,7 @@ func (s *DBService) batchSendSvcReq(req *wt.UpdateService, rollbackReq *wt.Updat
 	return
 }
 
-func (s *DBService) batchSendSingleSvcReq(req *wt.UpdateService, nodes []proto.NodeID) (err error) {
+func (s *DBService) batchSendSingleSvcReq(req *types.UpdateService, nodes []proto.NodeID) (err error) {
 	var wg sync.WaitGroup
 	errCh := make(chan error, len(nodes))
 
@@ -551,7 +550,7 @@ func (s *DBService) batchSendSingleSvcReq(req *wt.UpdateService, nodes []proto.N
 		wg.Add(1)
 		go func(s proto.NodeID, ec chan error) {
 			defer wg.Done()
-			var resp wt.UpdateServiceResponse
+			var resp types.UpdateServiceResponse
 			ec <- rpc.NewCaller().CallNode(s, route.DBSDeploy.String(), req, &resp)
 		}(node, errCh)
 	}
diff --git a/blockproducer/db_service_map.go b/blockproducer/db_service_map.go
index 6c260677a..1a56042a7 100644
--- a/blockproducer/db_service_map.go
+++ b/blockproducer/db_service_map.go
@@ -20,21 +20,21 @@ import (
 	"sync"
 
 	"github.com/CovenantSQL/CovenantSQL/proto"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/pkg/errors"
 )
 
 // DBMetaPersistence defines database meta persistence api.
 type DBMetaPersistence interface {
-	GetDatabase(dbID proto.DatabaseID) (wt.ServiceInstance, error)
-	SetDatabase(meta wt.ServiceInstance) error
+	GetDatabase(dbID proto.DatabaseID) (types.ServiceInstance, error)
+	SetDatabase(meta types.ServiceInstance) error
 	DeleteDatabase(dbID proto.DatabaseID) error
-	GetAllDatabases() ([]wt.ServiceInstance, error)
+	GetAllDatabases() ([]types.ServiceInstance, error)
 }
 
 // DBServiceMap defines database instance meta.
 type DBServiceMap struct {
-	dbMap   map[proto.DatabaseID]wt.ServiceInstance
+	dbMap   map[proto.DatabaseID]types.ServiceInstance
 	nodeMap map[proto.NodeID]map[proto.DatabaseID]bool
 	persist DBMetaPersistence
 	sync.RWMutex
@@ -44,7 +44,7 @@ type DBServiceMap struct {
 func InitServiceMap(persistImpl DBMetaPersistence) (s *DBServiceMap, err error) {
 	s = &DBServiceMap{
 		persist: persistImpl,
-		dbMap:   make(map[proto.DatabaseID]wt.ServiceInstance),
+		dbMap:   make(map[proto.DatabaseID]types.ServiceInstance),
 		nodeMap: make(map[proto.NodeID]map[proto.DatabaseID]bool),
 	}
 
@@ -52,7 +52,7 @@ func InitServiceMap(persistImpl DBMetaPersistence) (s *DBServiceMap, err error)
 	s.Lock()
 	defer s.Unlock()
 
-	var allDatabases []wt.ServiceInstance
+	var allDatabases []types.ServiceInstance
 
 	if allDatabases, err = s.persist.GetAllDatabases(); err != nil {
 		return
@@ -73,7 +73,7 @@ func InitServiceMap(persistImpl DBMetaPersistence) (s *DBServiceMap, err error)
 }
 
 // Set add database to meta.
-func (c *DBServiceMap) Set(meta wt.ServiceInstance) (err error) {
+func (c *DBServiceMap) Set(meta types.ServiceInstance) (err error) {
 	c.Lock()
 	defer c.Unlock()
 
@@ -82,7 +82,7 @@ func (c *DBServiceMap) Set(meta wt.ServiceInstance) (err error) {
 	}
 
 	// remove previous records
-	var oldMeta wt.ServiceInstance
+	var oldMeta types.ServiceInstance
 	var ok bool
 
 	if oldMeta, ok = c.dbMap[meta.DatabaseID]; ok {
@@ -110,7 +110,7 @@ func (c *DBServiceMap) Set(meta wt.ServiceInstance) (err error) {
 }
 
 // Get find database from meta.
-func (c *DBServiceMap) Get(dbID proto.DatabaseID) (meta wt.ServiceInstance, err error) {
+func (c *DBServiceMap) Get(dbID proto.DatabaseID) (meta types.ServiceInstance, err error) {
 	c.RLock()
 	defer c.RUnlock()
 
@@ -135,7 +135,7 @@ func (c *DBServiceMap) Delete(dbID proto.DatabaseID) (err error) {
 	c.Lock()
 	defer c.Unlock()
 
-	var meta wt.ServiceInstance
+	var meta types.ServiceInstance
 	var ok bool
 
 	// delete from cache
@@ -156,15 +156,15 @@ func (c *DBServiceMap) Delete(dbID proto.DatabaseID) (err error) {
 }
 
 // GetDatabases return database config.
-func (c *DBServiceMap) GetDatabases(nodeID proto.NodeID) (dbs []wt.ServiceInstance, err error) {
+func (c *DBServiceMap) GetDatabases(nodeID proto.NodeID) (dbs []types.ServiceInstance, err error) {
 	c.RLock()
 	defer c.RUnlock()
 
-	dbs = make([]wt.ServiceInstance, 0)
+	dbs = make([]types.ServiceInstance, 0)
 
 	for dbID, ok := range c.nodeMap[nodeID] {
 		if ok {
-			var db wt.ServiceInstance
+			var db types.ServiceInstance
 			if db, ok = c.dbMap[dbID]; ok {
 				dbs = append(dbs, db)
 			}
diff --git a/blockproducer/db_service_map_test.go b/blockproducer/db_service_map_test.go
index ed2afb375..b5fe441e9 100644
--- a/blockproducer/db_service_map_test.go
+++ b/blockproducer/db_service_map_test.go
@@ -26,7 +26,7 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	. "github.com/smartystreets/goconvey/convey"
 )
 
@@ -66,7 +66,7 @@ func TestServiceMap(t *testing.T) {
 		So(err, ShouldNotBeNil)
 
 		// test get exists
-		var instance wt.ServiceInstance
+		var instance types.ServiceInstance
 		instance, err = svcMap.Get(proto.DatabaseID("db"))
 		So(instance.DatabaseID, ShouldResemble, proto.DatabaseID("db"))
 
@@ -116,7 +116,7 @@ func TestServiceMap(t *testing.T) {
 		So(svcMap.dbMap, ShouldNotContainKey, proto.DatabaseID("db2"))
 
 		// test get databases
-		var instances []wt.ServiceInstance
+		var instances []types.ServiceInstance
 		instances, err = svcMap.GetDatabases(nodeID)
 		So(instances, ShouldHaveLength, 1)
 		So(instances[0].DatabaseID, ShouldResemble, proto.DatabaseID("db"))
diff --git a/blockproducer/db_service_test.go b/blockproducer/db_service_test.go
index 6c464256e..14d5b4d95 100644
--- a/blockproducer/db_service_test.go
+++ b/blockproducer/db_service_test.go
@@ -26,7 +26,7 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	. "github.com/smartystreets/goconvey/convey"
 )
 
@@ -71,20 +71,20 @@ func TestService(t *testing.T) {
 		So(err, ShouldBeNil)
 
 		// test get database
-		getReq := new(GetDatabaseRequest)
+		getReq := new(types.GetDatabaseRequest)
 		getReq.Header.DatabaseID = proto.DatabaseID("db")
 		err = getReq.Sign(privateKey)
 		So(err, ShouldBeNil)
 
-		getRes := new(GetDatabaseResponse)
+		getRes := new(types.GetDatabaseResponse)
 		err = rpc.NewCaller().CallNode(nodeID, route.BPDBGetDatabase.String(), getReq, getRes)
 		So(err, ShouldBeNil)
 		So(getReq.Verify(), ShouldBeNil)
 		So(getRes.Header.InstanceMeta.DatabaseID, ShouldResemble, proto.DatabaseID("db"))
 
 		// get node databases
-		getAllReq := new(wt.InitService)
-		getAllRes := new(wt.InitServiceResponse)
+		getAllReq := new(types.InitService)
+		getAllRes := new(types.InitServiceResponse)
 		err = rpc.NewCaller().CallNode(nodeID, route.BPDBGetNodeDatabases.String(), getAllReq, getAllRes)
 		So(err, ShouldBeNil)
 		So(getAllRes.Verify(), ShouldBeNil)
@@ -92,25 +92,25 @@ func TestService(t *testing.T) {
 		So(getAllRes.Header.Instances[0].DatabaseID, ShouldResemble, proto.DatabaseID("db"))
 
 		// create database, no metric received, should failed
-		createDBReq := new(CreateDatabaseRequest)
-		createDBReq.Header.ResourceMeta = wt.ResourceMeta{
+		createDBReq := new(types.CreateDatabaseRequest)
+		createDBReq.Header.ResourceMeta = types.ResourceMeta{
 			Node: 1,
 		}
 		err = createDBReq.Sign(privateKey)
 		So(err, ShouldBeNil)
-		createDBRes := new(CreateDatabaseResponse)
+		createDBRes := new(types.CreateDatabaseResponse)
 		err = rpc.NewCaller().CallNode(nodeID, route.BPDBCreateDatabase.String(), createDBReq, createDBRes)
 		So(err, ShouldNotBeNil)
 
 		// trigger metrics, but does not allow block producer to service as miner
 		metric.NewCollectClient().UploadMetrics(nodeID)
-		createDBRes = new(CreateDatabaseResponse)
+		createDBRes = new(types.CreateDatabaseResponse)
 		err = rpc.NewCaller().CallNode(nodeID, route.BPDBCreateDatabase.String(), createDBReq, createDBRes)
 		So(err, ShouldNotBeNil)
 
 		// allow block producer to service as miner, only use this in test case
 		dbService.includeBPNodesForAllocation = true
-		createDBRes = new(CreateDatabaseResponse)
+		createDBRes = new(types.CreateDatabaseResponse)
 		err = rpc.NewCaller().CallNode(nodeID, route.BPDBCreateDatabase.String(), createDBReq, createDBRes)
 		So(err, ShouldBeNil)
 		So(createDBRes.Verify(), ShouldBeNil)
@@ -133,16 +133,16 @@ func TestService(t *testing.T) {
 		// use the database
 		serverID := createDBRes.Header.InstanceMeta.Peers.Leader
 		dbID := createDBRes.Header.InstanceMeta.DatabaseID
-		var queryReq *wt.Request
-		queryReq, err = buildQuery(wt.WriteQuery, 1, 1, dbID, []string{
+		var queryReq *types.Request
+		queryReq, err = buildQuery(types.WriteQuery, 1, 1, dbID, []string{
 			"create table test (test int)",
 			"insert into test values(1)",
 		})
 		So(err, ShouldBeNil)
-		queryRes := new(wt.Response)
+		queryRes := new(types.Response)
 		err = rpc.NewCaller().CallNode(serverID, route.DBSQuery.String(), queryReq, queryRes)
 		So(err, ShouldBeNil)
-		queryReq, err = buildQuery(wt.ReadQuery, 1, 2, dbID, []string{
+		queryReq, err = buildQuery(types.ReadQuery, 1, 2, dbID, []string{
 			"select * from test",
 		})
 		So(err, ShouldBeNil)
@@ -158,16 +158,16 @@ func TestService(t *testing.T) {
 		So(queryRes.Payload.Rows[0].Values[0], ShouldEqual, 1)
 
 		// drop database
-		dropDBReq := new(DropDatabaseRequest)
+		dropDBReq := new(types.DropDatabaseRequest)
 		dropDBReq.Header.DatabaseID = createDBRes.Header.InstanceMeta.DatabaseID
 		err = dropDBReq.Sign(privateKey)
 		So(err, ShouldBeNil)
-		dropDBRes := new(DropDatabaseResponse)
+		dropDBRes := new(types.DropDatabaseResponse)
 		err = rpc.NewCaller().CallNode(nodeID, route.BPDBDropDatabase.String(), dropDBReq, dropDBRes)
 		So(err, ShouldBeNil)
 
 		// get this database again to test if it is dropped
-		getReq = new(GetDatabaseRequest)
+		getReq = new(types.GetDatabaseRequest)
 		getReq.Header.DatabaseID = createDBRes.Header.InstanceMeta.DatabaseID
 		err = getReq.Sign(privateKey)
 		So(err, ShouldBeNil)
@@ -176,7 +176,7 @@ func TestService(t *testing.T) {
 	})
 }
 
-func buildQuery(queryType wt.QueryType, connID uint64, seqNo uint64, databaseID proto.DatabaseID, queries []string) (query *wt.Request, err error) {
+func buildQuery(queryType types.QueryType, connID uint64, seqNo uint64, databaseID proto.DatabaseID, queries []string) (query *types.Request, err error) {
 	// get node id
 	var nodeID proto.NodeID
 	if nodeID, err = kms.GetLocalNodeID(); err != nil {
@@ -192,15 +192,15 @@ func buildQuery(queryType wt.QueryType, connID uint64, seqNo uint64, databaseID
 	tm := time.Now().UTC()
 
 	// build queries
-	realQueries := make([]wt.Query, len(queries))
+	realQueries := make([]types.Query, len(queries))
 
 	for i, v := range queries {
 		realQueries[i].Pattern = v
 	}
 
-	query = &wt.Request{
-		Header: wt.SignedRequestHeader{
-			RequestHeader: wt.RequestHeader{
+	query = &types.Request{
+		Header: types.SignedRequestHeader{
+			RequestHeader: types.RequestHeader{
 				DatabaseID:   databaseID,
 				QueryType:    queryType,
 				NodeID:       nodeID,
@@ -209,7 +209,7 @@ func buildQuery(queryType wt.QueryType, connID uint64, seqNo uint64, databaseID
 				Timestamp:    tm,
 			},
 		},
-		Payload: wt.RequestPayload{
+		Payload: types.RequestPayload{
 			Queries: realQueries,
 		},
 	}
diff --git a/blockproducer/errors.go b/blockproducer/errors.go
index b6ac4e352..a36b9d8a9 100644
--- a/blockproducer/errors.go
+++ b/blockproducer/errors.go
@@ -48,8 +48,6 @@ var (
 	ErrSmallerSequenceID = errors.New("SequanceID should be bigger than the old one")
 	// ErrInvalidBillingRequest defines BillingRequest is invalid
 	ErrInvalidBillingRequest = errors.New("The BillingRequest is invalid")
-	// ErrSignVerification indicates a failed signature verification.
-	ErrSignVerification = errors.New("signature verification failed")
 
 	// ErrBalanceOverflow indicates that there will be an overflow after balance manipulation.
 	ErrBalanceOverflow = errors.New("balance overflow")
diff --git a/blockproducer/helper_test.go b/blockproducer/helper_test.go
index a464632be..ce68aca12 100644
--- a/blockproducer/helper_test.go
+++ b/blockproducer/helper_test.go
@@ -38,11 +38,10 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
 	"github.com/CovenantSQL/CovenantSQL/worker"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 )
 
 const (
@@ -54,7 +53,7 @@ var (
 )
 
 // copied from sqlchain.xxx_test.
-func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error) {
+func createRandomBlock(parent hash.Hash, isGenesis bool) (b *types.Block, err error) {
 	// Generate key pair
 	priv, pub, err := asymmetric.GenSecp256k1KeyPair()
 
@@ -65,9 +64,9 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 	h := hash.Hash{}
 	rand.Read(h[:])
 
-	b = &ct.Block{
-		SignedHeader: ct.SignedHeader{
-			Header: ct.Header{
+	b = &types.Block{
+		SignedHeader: types.SignedHeader{
+			Header: types.Header{
 				Version:     0x01000000,
 				Producer:    proto.NodeID(h.String()),
 				GenesisHash: rootHash,
@@ -75,12 +74,6 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 				Timestamp:   time.Now().UTC(),
 			},
 		},
-		Queries: make([]*hash.Hash, rand.Intn(10)+10),
-	}
-
-	for i := range b.Queries {
-		b.Queries[i] = new(hash.Hash)
-		rand.Read(b.Queries[i][:])
 	}
 
 	if isGenesis {
@@ -113,7 +106,7 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 // fake a persistence driver.
 type stubDBMetaPersistence struct{}
 
-func (p *stubDBMetaPersistence) GetDatabase(dbID proto.DatabaseID) (instance wt.ServiceInstance, err error) {
+func (p *stubDBMetaPersistence) GetDatabase(dbID proto.DatabaseID) (instance types.ServiceInstance, err error) {
 	// for test purpose, name with db prefix consider it exists
 	if !strings.HasPrefix(string(dbID), "db") {
 		err = ErrNoSuchDatabase
@@ -123,7 +116,7 @@ func (p *stubDBMetaPersistence) GetDatabase(dbID proto.DatabaseID) (instance wt.
 	return p.getInstanceMeta(dbID)
 }
 
-func (p *stubDBMetaPersistence) SetDatabase(meta wt.ServiceInstance) (err error) {
+func (p *stubDBMetaPersistence) SetDatabase(meta types.ServiceInstance) (err error) {
 	return
 }
 
@@ -131,13 +124,13 @@ func (p *stubDBMetaPersistence) DeleteDatabase(dbID proto.DatabaseID) (err error
 	return
 }
 
-func (p *stubDBMetaPersistence) GetAllDatabases() (instances []wt.ServiceInstance, err error) {
-	instances = make([]wt.ServiceInstance, 1)
+func (p *stubDBMetaPersistence) GetAllDatabases() (instances []types.ServiceInstance, err error) {
+	instances = make([]types.ServiceInstance, 1)
 	instances[0], err = p.getInstanceMeta("db")
 	return
 }
 
-func (p *stubDBMetaPersistence) getInstanceMeta(dbID proto.DatabaseID) (instance wt.ServiceInstance, err error) {
+func (p *stubDBMetaPersistence) getInstanceMeta(dbID proto.DatabaseID) (instance types.ServiceInstance, err error) {
 	var privKey *asymmetric.PrivateKey
 	if privKey, err = kms.GetLocalPrivateKey(); err != nil {
 		return
diff --git a/chain/errors.go b/blockproducer/interfaces/mixins_test.go
similarity index 58%
rename from chain/errors.go
rename to blockproducer/interfaces/mixins_test.go
index f936a24db..48fca8eb0 100644
--- a/chain/errors.go
+++ b/blockproducer/interfaces/mixins_test.go
@@ -14,15 +14,19 @@
  * limitations under the License.
  */
 
-package chain
+package interfaces
 
-import "errors"
+import (
+	"testing"
 
-var (
-	// ErrUnknownTx indicates that the transaction is unknown.
-	ErrUnknownTx = errors.New("unknown transaction")
-	// ErrDuplicateTx indicates that the transaction will be duplicate in the new block.
-	ErrDuplicateTx = errors.New("duplicate transaction")
-	// ErrCorruptedIndex indicates that a corrupted index item is detected.
-	ErrCorruptedIndex = errors.New("corrupted index")
+	. "github.com/smartystreets/goconvey/convey"
 )
+
+func TestTransactionTypeMixin(t *testing.T) {
+	Convey("test transaction type mixin", t, func() {
+		m := NewTransactionTypeMixin(TransactionTypeBaseAccount)
+		So(m.GetTransactionType(), ShouldEqual, TransactionTypeBaseAccount)
+		m.SetTransactionType(TransactionTypeTransfer)
+		So(m.GetTransactionType(), ShouldEqual, TransactionTypeTransfer)
+	})
+}
diff --git a/blockproducer/interfaces/transaction.go b/blockproducer/interfaces/transaction.go
index f4916ac80..ba1d93a86 100644
--- a/blockproducer/interfaces/transaction.go
+++ b/blockproducer/interfaces/transaction.go
@@ -97,7 +97,7 @@ func (t TransactionType) String() string {
 type Transaction interface {
 	GetAccountAddress() proto.AccountAddress
 	GetAccountNonce() AccountNonce
-	GetHash() hash.Hash
+	Hash() hash.Hash
 	GetTransactionType() TransactionType
 	Sign(signer *asymmetric.PrivateKey) error
 	Verify() error
diff --git a/blockproducer/interfaces/transaction_test.go b/blockproducer/interfaces/transaction_test.go
index 07ecba4e8..7a80ac53b 100644
--- a/blockproducer/interfaces/transaction_test.go
+++ b/blockproducer/interfaces/transaction_test.go
@@ -54,4 +54,9 @@ func TestTypes(t *testing.T) {
 			So(h1, ShouldResemble, h2)
 		}
 	})
+	Convey("test string", t, func() {
+		for i := TransactionTypeBilling; i != TransactionTypeNumber+1; i++ {
+			So(i.String(), ShouldNotBeEmpty)
+		}
+	})
 }
diff --git a/blockproducer/interfaces/transaction_wrapper.go b/blockproducer/interfaces/transaction_wrapper.go
index 37948aa38..2c46b6cf7 100644
--- a/blockproducer/interfaces/transaction_wrapper.go
+++ b/blockproducer/interfaces/transaction_wrapper.go
@@ -77,14 +77,6 @@ func (w *TransactionWrapper) CodecEncodeSelf(e *codec.Encoder) {
 		return
 	}
 
-	// if the transaction is supports type transaction mixin
-	var rawTx interface{} = w.Transaction
-	if _, ok := rawTx.(ContainsTransactionTypeMixin); ok {
-		// encode directly
-		helperEncoder.EncFallback(w.Transaction)
-		return
-	}
-
 	// translate wrapper to two fields array wrapped by map
 	encDriver.WriteArrayStart(2)
 	encDriver.WriteArrayElem()
@@ -146,7 +138,6 @@ func (w *TransactionWrapper) decodeFromWrapper(d *codec.Decoder) {
 				helperDecoder.DecFallback(&w.Transaction, true)
 			}
 		} else {
-			helperDecoder.DecSwallow()
 			helperDecoder.DecStructFieldNotFound(i, "")
 		}
 	}
diff --git a/blockproducer/interfaces/transaction_wrapper_test.go b/blockproducer/interfaces/transaction_wrapper_test.go
new file mode 100644
index 000000000..a8d97608c
--- /dev/null
+++ b/blockproducer/interfaces/transaction_wrapper_test.go
@@ -0,0 +1,194 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package interfaces_test
+
+import (
+	"testing"
+
+	pi "github.com/CovenantSQL/CovenantSQL/blockproducer/interfaces"
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/utils"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+type TestTransactionEncode struct {
+	TestField int64
+	pi.TransactionTypeMixin
+}
+
+func (e *TestTransactionEncode) GetAccountAddress() proto.AccountAddress {
+	return proto.AccountAddress{}
+}
+
+func (e *TestTransactionEncode) GetAccountNonce() pi.AccountNonce {
+	return pi.AccountNonce(0)
+}
+
+func (e *TestTransactionEncode) Hash() hash.Hash {
+	return hash.Hash{}
+}
+
+func (e *TestTransactionEncode) Sign(signer *asymmetric.PrivateKey) error {
+	return nil
+}
+
+func (e *TestTransactionEncode) Verify() error {
+	return nil
+}
+func (e *TestTransactionEncode) MarshalHash() ([]byte, error) {
+	return nil, nil
+}
+
+func (e *TestTransactionEncode) Msgsize() int {
+	return 0
+}
+
+func init() {
+	pi.RegisterTransaction(pi.TransactionTypeBilling, (*TestTransactionEncode)(nil))
+}
+
+func TestTransactionWrapper(t *testing.T) {
+	Convey("tx wrapper test", t, func() {
+		w := &pi.TransactionWrapper{}
+		So(w.Unwrap(), ShouldBeNil)
+
+		// nil encode
+		buf, err := utils.EncodeMsgPack(w)
+		So(err, ShouldBeNil)
+		var v interface{}
+		err = utils.DecodeMsgPack(buf.Bytes(), &v)
+		So(err, ShouldBeNil)
+		So(v, ShouldBeNil)
+
+		// encode test
+		e := &TestTransactionEncode{}
+		e.SetTransactionType(pi.TransactionTypeBilling)
+		buf, err = utils.EncodeMsgPack(e)
+		So(err, ShouldBeNil)
+		var v2 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v2)
+		So(err, ShouldBeNil)
+		So(v2.GetTransactionType(), ShouldEqual, pi.TransactionTypeBilling)
+
+		// encode with wrapper test
+		e2 := pi.WrapTransaction(e)
+		buf, err = utils.EncodeMsgPack(e2)
+		So(err, ShouldBeNil)
+		var v3 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v3)
+		So(err, ShouldBeNil)
+		So(v3.GetTransactionType(), ShouldEqual, pi.TransactionTypeBilling)
+		tw, ok := v3.(*pi.TransactionWrapper)
+		So(ok, ShouldBeTrue)
+		So(tw.Unwrap().GetTransactionType(), ShouldEqual, pi.TransactionTypeBilling)
+
+		// test encode non-existence type
+		e3 := &TestTransactionEncode{}
+		e3.SetTransactionType(pi.TransactionTypeTransfer)
+		buf, err = utils.EncodeMsgPack(e3)
+		So(err, ShouldBeNil)
+		var v4 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v4)
+		So(err, ShouldNotBeNil)
+
+		// test invalid decode, not enough length
+		buf, err = utils.EncodeMsgPack([]uint64{})
+		So(err, ShouldBeNil)
+		var v5 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v5)
+		So(err, ShouldNotBeNil)
+
+		// test invalid decode, invalid tx type
+		buf, err = utils.EncodeMsgPack([]uint64{1})
+		So(err, ShouldBeNil)
+		var v6 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v6)
+		So(err, ShouldNotBeNil)
+
+		// test invalid decode, nil type
+		buf, err = utils.EncodeMsgPack([]interface{}{nil})
+		So(err, ShouldBeNil)
+		var v7 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v7)
+		So(err, ShouldNotBeNil)
+
+		// test invalid decode, nil payload
+		buf, err = utils.EncodeMsgPack([]interface{}{pi.TransactionTypeBilling, nil})
+		So(err, ShouldBeNil)
+		var v8 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v8)
+		So(err, ShouldNotBeNil)
+
+		// test invalid decode, invalid payload container type
+		buf, err = utils.EncodeMsgPack([]interface{}{pi.TransactionTypeBilling, []uint64{}})
+		So(err, ShouldBeNil)
+		var v9 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v9)
+		So(err, ShouldNotBeNil)
+
+		// extra payload
+		buf, err = utils.EncodeMsgPack([]interface{}{pi.TransactionTypeBilling, e, 1, 2})
+		So(err, ShouldBeNil)
+		var v10 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v10)
+		So(err, ShouldBeNil)
+
+		// test invalid type
+		buf, err = utils.EncodeMsgPack(1)
+		So(err, ShouldBeNil)
+		var v11 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v11)
+		So(err, ShouldNotBeNil)
+
+		// test invalid mixin
+		buf, err = utils.EncodeMsgPack(map[string]interface{}{"TxType": "invalid type"})
+		So(err, ShouldBeNil)
+		var v12 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v12)
+		So(err, ShouldNotBeNil)
+
+		// test invalid mixin type
+		buf, err = utils.EncodeMsgPack(map[string]interface{}{"TxType": pi.TransactionTypeNumber})
+		So(err, ShouldBeNil)
+		var v13 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v13)
+		So(err, ShouldNotBeNil)
+
+		// test tx data
+		buf, err = utils.EncodeMsgPack(map[string]interface{}{"TxType": pi.TransactionTypeBilling, "TestField": 1})
+		So(err, ShouldBeNil)
+		var v14 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v14)
+		So(err, ShouldBeNil)
+
+		// test invalid tx data
+		buf, err = utils.EncodeMsgPack(map[string]interface{}{"TxType": pi.TransactionTypeBilling, "TestField": "happy"})
+		So(err, ShouldBeNil)
+		var v15 pi.Transaction
+		err = utils.DecodeMsgPack(buf.Bytes(), &v15)
+		So(err, ShouldNotBeNil)
+	})
+}
+
+func TestRegisterTransaction(t *testing.T) {
+	Convey("test registration", t, func() {
+		So(func() { pi.RegisterTransaction(pi.TransactionTypeTransfer, nil) }, ShouldPanic)
+		So(func() { pi.RegisterTransaction(pi.TransactionTypeBaseAccount, (*pi.TransactionWrapper)(nil)) }, ShouldPanic)
+	})
+}
diff --git a/blockproducer/metastate.go b/blockproducer/metastate.go
index b4d1ae675..ec7814ae0 100644
--- a/blockproducer/metastate.go
+++ b/blockproducer/metastate.go
@@ -77,9 +77,6 @@ func (s *metaState) loadOrStoreAccountObject(
 
 func (s *metaState) loadAccountStableBalance(addr proto.AccountAddress) (b uint64, loaded bool) {
 	var o *accountObject
-	s.Lock()
-	defer s.Unlock()
-
 	defer func() {
 		log.WithFields(log.Fields{
 			"account": addr.String(),
@@ -87,6 +84,9 @@ func (s *metaState) loadAccountStableBalance(addr proto.AccountAddress) (b uint6
 			"loaded":  loaded,
 		}).Debug("queried stable account")
 	}()
+	
+	s.Lock()
+	defer s.Unlock()
 
 	if o, loaded = s.dirty.accounts[addr]; loaded && o != nil {
 		b = o.StableCoinBalance
@@ -101,9 +101,6 @@ func (s *metaState) loadAccountStableBalance(addr proto.AccountAddress) (b uint6
 
 func (s *metaState) loadAccountCovenantBalance(addr proto.AccountAddress) (b uint64, loaded bool) {
 	var o *accountObject
-	s.Lock()
-	defer s.Unlock()
-
 	defer func() {
 		log.WithFields(log.Fields{
 			"account": addr.String(),
@@ -112,6 +109,9 @@ func (s *metaState) loadAccountCovenantBalance(addr proto.AccountAddress) (b uin
 		}).Debug("queried covenant account")
 	}()
 
+	s.Lock()
+	defer s.Unlock()
+
 	if o, loaded = s.dirty.accounts[addr]; loaded && o != nil {
 		b = o.CovenantCoinBalance
 		return
@@ -711,7 +711,7 @@ func (s *metaState) applyTransactionProcedure(t pi.Transaction) (_ func(*bolt.Tx
 
 	var (
 		enc   *bytes.Buffer
-		hash  = t.GetHash()
+		hash  = t.Hash()
 		addr  = t.GetAccountAddress()
 		nonce = t.GetAccountNonce()
 		ttype = t.GetTransactionType()
diff --git a/blockproducer/rpc.go b/blockproducer/rpc.go
index 358e5bad0..1fafe2f2d 100644
--- a/blockproducer/rpc.go
+++ b/blockproducer/rpc.go
@@ -18,9 +18,9 @@ package blockproducer
 
 import (
 	pi "github.com/CovenantSQL/CovenantSQL/blockproducer/interfaces"
-	"github.com/CovenantSQL/CovenantSQL/blockproducer/types"
+	pt "github.com/CovenantSQL/CovenantSQL/blockproducer/types"
 	"github.com/CovenantSQL/CovenantSQL/proto"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 )
 
 // ChainRPCService defines a main chain RPC server.
@@ -31,7 +31,7 @@ type ChainRPCService struct {
 // AdviseNewBlockReq defines a request of the AdviseNewBlock RPC method.
 type AdviseNewBlockReq struct {
 	proto.Envelope
-	Block *types.Block
+	Block *pt.Block
 }
 
 // AdviseNewBlockResp defines a response of the AdviseNewBlock RPC method.
@@ -42,7 +42,7 @@ type AdviseNewBlockResp struct {
 // AdviseTxBillingReq defines a request of the AdviseTxBilling RPC method.
 type AdviseTxBillingReq struct {
 	proto.Envelope
-	TxBilling *types.Billing
+	TxBilling *pt.Billing
 }
 
 // AdviseTxBillingResp defines a response of the AdviseTxBilling RPC method.
@@ -61,7 +61,7 @@ type FetchBlockResp struct {
 	proto.Envelope
 	Height uint32
 	Count  uint32
-	Block  *types.Block
+	Block  *pt.Block
 }
 
 // FetchBlockByCountReq define a request of the FetchBlockByCount RPC method.
@@ -135,11 +135,11 @@ type QueryAccountCovenantBalanceResp struct {
 // AdviseNewBlock is the RPC method to advise a new block to target server.
 func (s *ChainRPCService) AdviseNewBlock(req *AdviseNewBlockReq, resp *AdviseNewBlockResp) error {
 	s.chain.blocksFromRPC <- req.Block
-	return s.chain.pushBlock(req.Block)
+	return nil
 }
 
 // AdviseBillingRequest is the RPC method to advise a new billing request to main chain.
-func (s *ChainRPCService) AdviseBillingRequest(req *ct.AdviseBillingReq, resp *ct.AdviseBillingResp) error {
+func (s *ChainRPCService) AdviseBillingRequest(req *types.AdviseBillingReq, resp *types.AdviseBillingResp) error {
 	response, err := s.chain.produceBilling(req.Req)
 	if err != nil {
 		return err
diff --git a/blockproducer/txpool.go b/blockproducer/txpool.go
index 4fd46f683..41b714ae7 100644
--- a/blockproducer/txpool.go
+++ b/blockproducer/txpool.go
@@ -94,7 +94,7 @@ func (p *txPool) hasTx(tx pi.Transaction) (ok bool) {
 		return
 	}
 	// Check transaction hash
-	if ok = (tx.GetHash() == te.transactions[index].GetHash()); !ok {
+	if ok = (tx.Hash() == te.transactions[index].Hash()); !ok {
 		log.Debug("transaction hash already exists")
 		return
 	}
@@ -112,7 +112,7 @@ func (p *txPool) cmpAndMoveNextTx(tx pi.Transaction) (ok bool) {
 		return
 	}
 	// Check transaction hash
-	if ok = (tx.GetHash() == te.transactions[0].GetHash()); !ok {
+	if ok = (tx.Hash() == te.transactions[0].Hash()); !ok {
 		return
 	}
 	// Move forward
diff --git a/blockproducer/types/baseaccount.go b/blockproducer/types/baseaccount.go
index ce4facda1..c56b7a421 100644
--- a/blockproducer/types/baseaccount.go
+++ b/blockproducer/types/baseaccount.go
@@ -50,8 +50,8 @@ func (b *BaseAccount) GetAccountNonce() pi.AccountNonce {
 	return pi.AccountNonce(0)
 }
 
-// GetHash implements interfaces/Transaction.GetHash.
-func (b *BaseAccount) GetHash() (h hash.Hash) {
+// Hash implements interfaces/Transaction.Hash.
+func (b *BaseAccount) Hash() (h hash.Hash) {
 	return
 }
 
diff --git a/blockproducer/types/baseaccount_test.go b/blockproducer/types/baseaccount_test.go
new file mode 100644
index 000000000..fd1370735
--- /dev/null
+++ b/blockproducer/types/baseaccount_test.go
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestBaseAccount(t *testing.T) {
+	Convey("base account", t, func() {
+		h, err := hash.NewHashFromStr("000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade")
+		So(err, ShouldBeNil)
+		addr := proto.AccountAddress(*h)
+		ba := NewBaseAccount(&Account{
+			Address: addr,
+		})
+		So(ba.GetAccountAddress(), ShouldEqual, addr)
+		So(ba.GetAccountNonce(), ShouldEqual, 0)
+		So(ba.Hash(), ShouldEqual, hash.Hash{})
+		priv, _, err := asymmetric.GenSecp256k1KeyPair()
+		So(err, ShouldBeNil)
+		So(ba.Sign(priv), ShouldBeNil)
+		So(ba.Verify(), ShouldBeNil)
+	})
+}
diff --git a/blockproducer/types/billing.go b/blockproducer/types/billing.go
index 0beeb86f7..ba959981c 100644
--- a/blockproducer/types/billing.go
+++ b/blockproducer/types/billing.go
@@ -19,6 +19,7 @@ package types
 import (
 	pi "github.com/CovenantSQL/CovenantSQL/blockproducer/interfaces"
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
 	"github.com/CovenantSQL/CovenantSQL/proto"
 )
 
@@ -56,7 +57,7 @@ func NewBillingHeader(nonce pi.AccountNonce, bReq *BillingRequest, producer prot
 type Billing struct {
 	BillingHeader
 	pi.TransactionTypeMixin
-	DefaultHashSignVerifierImpl
+	verifier.DefaultHashSignVerifierImpl
 }
 
 // NewBilling generates a new Billing.
diff --git a/blockproducer/types/billing_gen.go b/blockproducer/types/billing_gen.go
index 5260f1a35..bc636474f 100644
--- a/blockproducer/types/billing_gen.go
+++ b/blockproducer/types/billing_gen.go
@@ -18,13 +18,13 @@ func (z *Billing) MarshalHash() (o []byte, err error) {
 		o = hsp.AppendBytes(o, oTemp)
 	}
 	o = append(o, 0x83)
-	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+	if oTemp, err := z.TransactionTypeMixin.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
 	}
 	o = append(o, 0x83)
-	if oTemp, err := z.TransactionTypeMixin.MarshalHash(); err != nil {
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -34,7 +34,7 @@ func (z *Billing) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *Billing) Msgsize() (s int) {
-	s = 1 + 14 + z.BillingHeader.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize() + 21 + z.TransactionTypeMixin.Msgsize()
+	s = 1 + 14 + z.BillingHeader.Msgsize() + 21 + z.TransactionTypeMixin.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
 	return
 }
 
diff --git a/blockproducer/types/billing_test.go b/blockproducer/types/billing_test.go
index bafa32c10..1c3d6e0c2 100644
--- a/blockproducer/types/billing_test.go
+++ b/blockproducer/types/billing_test.go
@@ -82,13 +82,13 @@ func TestBilling_SerializeDeserialize(t *testing.T) {
 	}
 
 	if !tb.Signature.IsEqual(dec.Signature) {
-		t.Fatalf("Value not match: \n\tv1=%v\n\tv2=%v", tb.Signature, tb.Signature)
+		t.Fatalf("Value not match: \n\tv1=%v\n\tv2=%v", tb.Signature, dec.Signature)
 	}
 	if !tb.Signee.IsEqual(dec.Signee) {
-		t.Fatalf("Value not match: \n\tv1=%v\n\tv2=%v", tb.Signee, tb.Signee)
+		t.Fatalf("Value not match: \n\tv1=%v\n\tv2=%v", tb.Signee, dec.Signee)
 	}
-	if !tb.Hash.IsEqual(&dec.Hash) {
-		t.Fatalf("Value not match: \n\tv1=%v\n\tv2=%v", tb.Hash, tb.Hash)
+	if tb.Hash() != dec.Hash() {
+		t.Fatalf("Value not match: \n\tv1=%v\n\tv2=%v", tb.Hash(), dec.Hash())
 	}
 }
 
@@ -120,4 +120,22 @@ func TestBilling_PackAndSignTx(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Verify signature failed: %v", err)
 	}
+
+	// get
+	addr := hash.Hash(tb.GetAccountAddress())
+	if addr.IsEqual(&hash.Hash{}) {
+		t.Fatal("Get hash failed")
+	}
+
+	tb.GetAccountNonce()
+
+	if tb.GetDatabaseID() == nil {
+		t.Fatal("Get nil DatabaseID")
+	}
+
+	tb.Signature = nil
+	err = tb.Verify()
+	if err == nil {
+		t.Fatal("Verify signature should failed")
+	}
 }
diff --git a/blockproducer/types/block.go b/blockproducer/types/block.go
index a2f88d642..42bb57714 100644
--- a/blockproducer/types/block.go
+++ b/blockproducer/types/block.go
@@ -67,7 +67,7 @@ func (b *Block) GetTxHashes() []*hash.Hash {
 	hs := make([]*hash.Hash, len(b.Transactions))
 
 	for i, v := range b.Transactions {
-		h := v.GetHash()
+		h := v.Hash()
 		hs[i] = &h
 	}
 	return hs
diff --git a/blockproducer/types/createdb.go b/blockproducer/types/createdb.go
index 2d5aa00fa..33749fcb9 100644
--- a/blockproducer/types/createdb.go
+++ b/blockproducer/types/createdb.go
@@ -19,6 +19,7 @@ package types
 import (
 	pi "github.com/CovenantSQL/CovenantSQL/blockproducer/interfaces"
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
 	"github.com/CovenantSQL/CovenantSQL/proto"
 )
 
@@ -44,7 +45,7 @@ func (h *CreateDatabaseHeader) GetAccountNonce() pi.AccountNonce {
 type CreateDatabase struct {
 	CreateDatabaseHeader
 	pi.TransactionTypeMixin
-	DefaultHashSignVerifierImpl
+	verifier.DefaultHashSignVerifierImpl
 }
 
 // NewCreateDatabase returns new instance.
diff --git a/blockproducer/types/createdb_gen.go b/blockproducer/types/createdb_gen.go
index 0b3e6b862..2d4f51a21 100644
--- a/blockproducer/types/createdb_gen.go
+++ b/blockproducer/types/createdb_gen.go
@@ -25,13 +25,13 @@ func (z *CreateDatabase) MarshalHash() (o []byte, err error) {
 		o = hsp.AppendBytes(o, oTemp)
 	}
 	o = append(o, 0x83)
-	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+	if oTemp, err := z.TransactionTypeMixin.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
 	}
 	o = append(o, 0x83)
-	if oTemp, err := z.TransactionTypeMixin.MarshalHash(); err != nil {
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -41,7 +41,7 @@ func (z *CreateDatabase) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *CreateDatabase) Msgsize() (s int) {
-	s = 1 + 21 + 1 + 6 + z.CreateDatabaseHeader.Owner.Msgsize() + 6 + z.CreateDatabaseHeader.Nonce.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize() + 21 + z.TransactionTypeMixin.Msgsize()
+	s = 1 + 21 + 1 + 6 + z.CreateDatabaseHeader.Owner.Msgsize() + 6 + z.CreateDatabaseHeader.Nonce.Msgsize() + 21 + z.TransactionTypeMixin.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
 	return
 }
 
diff --git a/blockproducer/types/createdb_test.go b/blockproducer/types/createdb_test.go
new file mode 100644
index 000000000..e61381a4b
--- /dev/null
+++ b/blockproducer/types/createdb_test.go
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestTxCreateDatabase(t *testing.T) {
+	Convey("test tx create database", t, func() {
+		h, err := hash.NewHashFromStr("000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade")
+		So(err, ShouldBeNil)
+		addr := proto.AccountAddress(*h)
+
+		cd := NewCreateDatabase(&CreateDatabaseHeader{
+			Owner: addr,
+			Nonce: 1,
+		})
+
+		So(cd.GetAccountAddress(), ShouldEqual, addr)
+		So(cd.GetAccountNonce(), ShouldEqual, 1)
+
+		priv, _, err := asymmetric.GenSecp256k1KeyPair()
+		So(err, ShouldBeNil)
+
+		err = cd.Sign(priv)
+		So(err, ShouldBeNil)
+
+		err = cd.Verify()
+		So(err, ShouldBeNil)
+	})
+}
diff --git a/blockproducer/types/msgpack_test.go b/blockproducer/types/msgpack_test.go
index c448c3af6..838f244de 100644
--- a/blockproducer/types/msgpack_test.go
+++ b/blockproducer/types/msgpack_test.go
@@ -106,21 +106,6 @@ func TestEncodeDecodeTransactions(t *testing.T) {
 			So(reflect.TypeOf(out.Maps[k]).String(), ShouldContainSubstring, "TransactionWrapper")
 		}
 	})
-	Convey("test encode wrapper, decode using real type", t, func() {
-		var t pi.Transaction
-		t = pi.WrapTransaction(NewBaseAccount(&Account{}))
-		So(reflect.TypeOf(t).String(), ShouldContainSubstring, "TransactionWrapper")
-		So(t.GetTransactionType(), ShouldEqual, pi.TransactionTypeBaseAccount)
-		buf, err := utils.EncodeMsgPack(t)
-		So(err, ShouldBeNil)
-
-		var out *BaseAccount
-		err = utils.DecodeMsgPack(buf.Bytes(), &out)
-		So(err, ShouldBeNil)
-		So(out, ShouldNotBeNil)
-		So(out.GetTransactionType(), ShouldEqual, pi.TransactionTypeBaseAccount)
-		So(reflect.TypeOf(out).String(), ShouldContainSubstring, "BaseAccount")
-	})
 	Convey("decode invalid data", t, func() {
 		var testTypes = []interface{}{
 			"1",
diff --git a/blockproducer/types/transfer.go b/blockproducer/types/transfer.go
index e9a170fa0..38d6f7134 100644
--- a/blockproducer/types/transfer.go
+++ b/blockproducer/types/transfer.go
@@ -19,6 +19,7 @@ package types
 import (
 	pi "github.com/CovenantSQL/CovenantSQL/blockproducer/interfaces"
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
 	"github.com/CovenantSQL/CovenantSQL/proto"
 )
 
@@ -35,7 +36,7 @@ type TransferHeader struct {
 type Transfer struct {
 	TransferHeader
 	pi.TransactionTypeMixin
-	DefaultHashSignVerifierImpl
+	verifier.DefaultHashSignVerifierImpl
 }
 
 // NewTransfer returns new instance.
diff --git a/blockproducer/types/transfer_gen.go b/blockproducer/types/transfer_gen.go
index 6d910fa70..c2f7f8736 100644
--- a/blockproducer/types/transfer_gen.go
+++ b/blockproducer/types/transfer_gen.go
@@ -12,19 +12,19 @@ func (z *Transfer) MarshalHash() (o []byte, err error) {
 	o = hsp.Require(b, z.Msgsize())
 	// map header, size 3
 	o = append(o, 0x83, 0x83)
-	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+	if oTemp, err := z.TransferHeader.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
 	}
 	o = append(o, 0x83)
-	if oTemp, err := z.TransferHeader.MarshalHash(); err != nil {
+	if oTemp, err := z.TransactionTypeMixin.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
 	}
 	o = append(o, 0x83)
-	if oTemp, err := z.TransactionTypeMixin.MarshalHash(); err != nil {
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -34,7 +34,7 @@ func (z *Transfer) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *Transfer) Msgsize() (s int) {
-	s = 1 + 28 + z.DefaultHashSignVerifierImpl.Msgsize() + 15 + z.TransferHeader.Msgsize() + 21 + z.TransactionTypeMixin.Msgsize()
+	s = 1 + 15 + z.TransferHeader.Msgsize() + 21 + z.TransactionTypeMixin.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
 	return
 }
 
diff --git a/blockproducer/types/transfer_test.go b/blockproducer/types/transfer_test.go
index 28c02e239..e651054b7 100644
--- a/blockproducer/types/transfer_test.go
+++ b/blockproducer/types/transfer_test.go
@@ -15,3 +15,32 @@
  */
 
 package types
+
+import (
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestTxTransfer(t *testing.T) {
+	Convey("test transfer", t, func() {
+		h, err := hash.NewHashFromStr("000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade")
+		So(err, ShouldBeNil)
+		addr := proto.AccountAddress(*h)
+
+		t := NewTransfer(&TransferHeader{
+			Sender: addr,
+			Nonce:  1,
+		})
+		So(t.GetAccountAddress(), ShouldEqual, addr)
+		So(t.GetAccountNonce(), ShouldEqual, 1)
+
+		priv, _, err := asymmetric.GenSecp256k1KeyPair()
+		So(err, ShouldBeNil)
+		So(t.Sign(priv), ShouldBeNil)
+		So(t.Verify(), ShouldBeNil)
+	})
+}
diff --git a/build.sh b/build.sh
index f856edc00..fc39ea309 100755
--- a/build.sh
+++ b/build.sh
@@ -37,6 +37,9 @@ go test -coverpkg github.com/CovenantSQL/CovenantSQL/... -cover -race -c -tags '
 cli_pkgpath="github.com/CovenantSQL/CovenantSQL/cmd/cql"
 CGO_ENABLED=1 go build -ldflags "-X main.version=${version} -X github.com/CovenantSQL/CovenantSQL/conf.RoleTag=C ${GOLDFLAGS}" --tags ${platform}" sqlite_omit_load_extension" -o bin/cql ${cli_pkgpath}
 
+fuse_pkgpath="github.com/CovenantSQL/CovenantSQL/cmd/cql-fuse"
+CGO_ENABLED=1 go build -ldflags "-X main.version=${version} -X github.com/CovenantSQL/CovenantSQL/conf.RoleTag=C ${GOLDFLAGS}" --tags ${platform}" sqlite_omit_load_extension" -o bin/cql-fuse ${fuse_pkgpath}
+
 cql_adapter_pkgpath="github.com/CovenantSQL/CovenantSQL/cmd/cql-adapter"
 CGO_ENABLED=1 go build -ldflags "-X main.version=${version} -X github.com/CovenantSQL/CovenantSQL/conf.RoleTag=C ${GOLDFLAGS}" --tags ${platform}" sqlite_omit_load_extension" -o bin/cql-adapter ${cql_adapter_pkgpath}
 
diff --git a/chain/interfaces/transaction.go b/chain/interfaces/transaction.go
deleted file mode 100644
index 12f07957f..000000000
--- a/chain/interfaces/transaction.go
+++ /dev/null
@@ -1,49 +0,0 @@
-/*
- * Copyright 2018 The CovenantSQL Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package interfaces
-
-import (
-	"time"
-
-	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
-	"github.com/CovenantSQL/CovenantSQL/proto"
-)
-
-// Serializer is the interface implemented by an object that can serialize itself into binary form.
-type Serializer interface {
-	Serialize() ([]byte, error)
-}
-
-// Deserializer is the interface implemented by an object that can deserialize a binary
-// representation of itself.
-type Deserializer interface {
-	Deserialize(enc []byte) error
-}
-
-// Transaction is the interface implemented by an object that can be verified and processed by
-// a blockchain as a transaction.
-type Transaction interface {
-	Serializer
-	Deserializer
-	GetDatabaseID() *proto.DatabaseID
-	GetHash() hash.Hash
-	GetIndexKey() interface{}
-	GetPersistenceKey() []byte
-	GetSequenceID() uint32
-	GetTime() time.Time
-	Verify() error
-}
diff --git a/chain/persistence.go b/chain/persistence.go
deleted file mode 100644
index 3cb46e4d7..000000000
--- a/chain/persistence.go
+++ /dev/null
@@ -1,124 +0,0 @@
-/*
- * Copyright 2018 The CovenantSQL Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package chain
-
-import (
-	ci "github.com/CovenantSQL/CovenantSQL/chain/interfaces"
-	"github.com/coreos/bbolt"
-)
-
-var (
-	metaBucket        = [4]byte{0x0, 0x0, 0x0, 0x0}
-	metaTxIndexBucket = []byte("covenantsql-tx-index-bucket")
-)
-
-// TxPersistence defines a persistence storage for blockchain transactions.
-type TxPersistence struct {
-	db *bolt.DB
-}
-
-// NewTxPersistence returns a new TxPersistence instance using the given bolt database as
-// underlying storage engine.
-func NewTxPersistence(db *bolt.DB) (ins *TxPersistence, err error) {
-	// Initialize buckets
-	if err = db.Update(func(tx *bolt.Tx) (err error) {
-		meta, err := tx.CreateBucketIfNotExists(metaBucket[:])
-		if err != nil {
-			return
-		}
-		_, err = meta.CreateBucketIfNotExists(metaTxIndexBucket)
-		return
-	}); err != nil {
-		return
-	}
-	// Create instance if succeed
-	ins = &TxPersistence{db: db}
-	return
-}
-
-// PutTransaction serializes and puts the transaction tx into the storage.
-func (p *TxPersistence) PutTransaction(tx ci.Transaction) (err error) {
-	var key, value []byte
-	key = tx.GetPersistenceKey()
-	if value, err = tx.Serialize(); err != nil {
-		return
-	}
-	return p.db.Update(func(tx *bolt.Tx) error {
-		return tx.Bucket(metaBucket[:]).Bucket(metaTxIndexBucket).Put(key, value)
-	})
-}
-
-// GetTransaction gets the transaction binary representation from the storage with key and
-// deserialize to tx.
-//
-// It is important that tx must provide an interface with corresponding concrete value, or the
-// deserialization will cause unexpected error.
-func (p *TxPersistence) GetTransaction(key []byte, tx ci.Transaction) (ok bool, err error) {
-	var value []byte
-	if err = p.db.View(func(tx *bolt.Tx) error {
-		value = tx.Bucket(metaBucket[:]).Bucket(metaTxIndexBucket).Get(key)
-		return nil
-	}); err != nil {
-		return
-	}
-	if value != nil {
-		ok = true
-		err = tx.Deserialize(value)
-		return
-	}
-	return
-}
-
-// DelTransaction deletes the transaction from the storage with key.
-func (p *TxPersistence) DelTransaction(key []byte) (err error) {
-	return p.db.Update(func(tx *bolt.Tx) error {
-		return tx.Bucket(metaBucket[:]).Bucket(metaTxIndexBucket).Delete(key)
-	})
-}
-
-// PutTransactionAndUpdateIndex serializes and puts the transaction from the storage with key
-// and updates transaction index ti in a single database transaction.
-func (p *TxPersistence) PutTransactionAndUpdateIndex(tx ci.Transaction, ti *TxIndex) (err error) {
-	var (
-		key = tx.GetPersistenceKey()
-		val []byte
-	)
-	if val, err = tx.Serialize(); err != nil {
-		return
-	}
-	return p.db.Update(func(dbtx *bolt.Tx) (err error) {
-		if err = dbtx.Bucket(metaBucket[:]).Bucket(metaTxIndexBucket).Put(key, val); err != nil {
-			return
-		}
-		ti.StoreTx(tx)
-		return
-	})
-}
-
-// DelTransactionAndUpdateIndex deletes the transaction from the storage with key and updates
-// transaction index ti in a single database transaction.
-func (p *TxPersistence) DelTransactionAndUpdateIndex(
-	pkey []byte, ikey interface{}, ti *TxIndex) (err error,
-) {
-	return p.db.Update(func(dbtx *bolt.Tx) (err error) {
-		if err = dbtx.Bucket(metaBucket[:]).Bucket(metaTxIndexBucket).Delete(pkey); err != nil {
-			return
-		}
-		ti.DelTx(ikey)
-		return
-	})
-}
diff --git a/chain/persistence_test.go b/chain/persistence_test.go
deleted file mode 100644
index 963ca08fc..000000000
--- a/chain/persistence_test.go
+++ /dev/null
@@ -1,159 +0,0 @@
-/*
- * Copyright 2018 The CovenantSQL Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package chain
-
-import (
-	"fmt"
-	"path"
-	"reflect"
-	"testing"
-
-	ci "github.com/CovenantSQL/CovenantSQL/chain/interfaces"
-	"github.com/coreos/bbolt"
-)
-
-func TestBadNewTxPersistence(t *testing.T) {
-	fl := path.Join(testDataDir, fmt.Sprintf("%s.db", t.Name()))
-	db, err := bolt.Open(fl, 0600, nil)
-	if err = db.Close(); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-	if _, err = NewTxPersistence(db); err == nil {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-}
-
-func TestTxPersistenceWithClosedDB(t *testing.T) {
-	fl := path.Join(testDataDir, fmt.Sprintf("%s.db", t.Name()))
-	db, err := bolt.Open(fl, 0600, nil)
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-	tp, err := NewTxPersistence(db)
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-	if err = db.Close(); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-	var (
-		otx ci.Transaction = newRandomDemoTxImpl()
-		rtx ci.Transaction = &DemoTxImpl{}
-	)
-	if _, err := tp.GetTransaction(otx.GetPersistenceKey(), rtx); err == nil {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-	if err = tp.PutTransaction(otx); err == nil {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-	if err = tp.DelTransaction(otx.GetPersistenceKey()); err == nil {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-}
-
-func TestTxPersistence(t *testing.T) {
-	fl := path.Join(testDataDir, fmt.Sprintf("%s.db", t.Name()))
-	db, err := bolt.Open(fl, 0600, nil)
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-	tp, err := NewTxPersistence(db)
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	// Test operations: Get -> Put -> Get -> Del -> Get
-	var (
-		otx ci.Transaction = newRandomDemoTxImpl()
-		rtx ci.Transaction = &DemoTxImpl{}
-	)
-	if ok, err := tp.GetTransaction(otx.GetPersistenceKey(), rtx); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	} else if ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if err = tp.PutTransaction(otx); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-	if ok, err := tp.GetTransaction(otx.GetPersistenceKey(), rtx); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	} else if !ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	} else if !reflect.DeepEqual(otx, rtx) {
-		t.Fatalf("Unexpected result:\n\torigin = %v\n\toutput = %v", otx, rtx)
-	}
-	if err = tp.DelTransaction(otx.GetPersistenceKey()); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-	if ok, err := tp.GetTransaction(otx.GetPersistenceKey(), rtx); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	} else if ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-}
-
-func TestTxPersistenceWithIndex(t *testing.T) {
-	fl := path.Join(testDataDir, fmt.Sprintf("%s.db", t.Name()))
-	db, err := bolt.Open(fl, 0600, nil)
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-	tp, err := NewTxPersistence(db)
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-	ti := NewTxIndex()
-
-	// Test operations: Get -> Put -> Get -> Del -> Get
-	var (
-		otx ci.Transaction = newRandomDemoTxImpl()
-		rtx ci.Transaction = &DemoTxImpl{}
-	)
-	if ok, err := tp.GetTransaction(otx.GetPersistenceKey(), rtx); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	} else if ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if err = tp.PutTransactionAndUpdateIndex(otx, ti); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-	if ok, err := tp.GetTransaction(otx.GetPersistenceKey(), rtx); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	} else if !ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	} else if !reflect.DeepEqual(otx, rtx) {
-		t.Fatalf("Unexpected result:\n\torigin = %v\n\toutput = %v", otx, rtx)
-	}
-	if xtx, ok := ti.LoadTx(otx.GetIndexKey()); !ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	} else if !reflect.DeepEqual(otx, xtx) {
-		t.Fatalf("Unexpected result:\n\torigin = %v\n\toutput = %v", otx, xtx)
-	}
-	if err = tp.DelTransactionAndUpdateIndex(
-		otx.GetPersistenceKey(), otx.GetIndexKey(), ti,
-	); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-	if ok, err := tp.GetTransaction(otx.GetPersistenceKey(), rtx); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	} else if ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if _, ok := ti.LoadTx(otx.GetIndexKey()); ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-}
diff --git a/chain/txindex.go b/chain/txindex.go
deleted file mode 100644
index 5d764e972..000000000
--- a/chain/txindex.go
+++ /dev/null
@@ -1,125 +0,0 @@
-/*
- * Copyright 2018 The CovenantSQL Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package chain
-
-import (
-	"sync"
-
-	ci "github.com/CovenantSQL/CovenantSQL/chain/interfaces"
-	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
-)
-
-type txCache struct {
-	bh *hash.Hash
-	tx ci.Transaction
-}
-
-// TxIndex defines transaction index.
-type TxIndex struct {
-	index sync.Map
-}
-
-// NewTxIndex returns a new TxIndex instance.
-func NewTxIndex() *TxIndex {
-	return &TxIndex{}
-}
-
-// StoreTx stores tx in the transaction index.
-func (i *TxIndex) StoreTx(tx ci.Transaction) {
-	i.index.Store(tx.GetIndexKey(), &txCache{tx: tx})
-}
-
-// HasTx returns a boolean value indicating wether the transaction index has key or not.
-func (i *TxIndex) HasTx(key interface{}) (ok bool) {
-	_, ok = i.index.Load(key)
-	return
-}
-
-// LoadTx loads a transaction with key.
-func (i *TxIndex) LoadTx(key interface{}) (tx ci.Transaction, ok bool) {
-	var (
-		val interface{}
-		tc  *txCache
-	)
-	if val, ok = i.index.Load(key); ok {
-		if tc = val.(*txCache); tc != nil {
-			tx = tc.tx
-		}
-	}
-	return
-}
-
-// SetBlock sets the block hash filed of txCache with key in the transaction index.
-func (i *TxIndex) SetBlock(key interface{}, bh hash.Hash) (ok bool) {
-	var (
-		val interface{}
-		tc  *txCache
-	)
-	if val, ok = i.index.Load(key); ok {
-		if tc = val.(*txCache); tc != nil {
-			tc.bh = &bh
-		}
-	}
-	return
-}
-
-// DelTx deletes transaction with key in the transaction index.
-func (i *TxIndex) DelTx(key interface{}) {
-	i.index.Delete(key)
-}
-
-// ResetBlock resets the block hash field of txCache with key in the transaction index.
-func (i *TxIndex) ResetBlock(key interface{}) (ok bool) {
-	var (
-		val interface{}
-		tc  *txCache
-	)
-	if val, ok = i.index.Load(key); ok {
-		if tc = val.(*txCache); tc != nil {
-			tc.bh = nil
-		}
-	}
-	return
-}
-
-// CheckTxState checks the transaction state for block packing with key in the transaction index.
-func (i *TxIndex) CheckTxState(key interface{}) error {
-	var (
-		ok  bool
-		val interface{}
-	)
-	if val, ok = i.index.Load(key); !ok {
-		return ErrUnknownTx
-	}
-	if tc := val.(*txCache); tc == nil {
-		return ErrCorruptedIndex
-	} else if tc.bh != nil {
-		return ErrDuplicateTx
-	}
-	return nil
-}
-
-// FetchUnpackedTxes fetches all unpacked tranactions and returns them as a slice.
-func (i *TxIndex) FetchUnpackedTxes() (txes []ci.Transaction) {
-	i.index.Range(func(key interface{}, val interface{}) bool {
-		if tc := val.(*txCache); tc != nil && tc.bh == nil {
-			txes = append(txes, tc.tx)
-		}
-		return true
-	})
-	return
-}
diff --git a/chain/txindex_test.go b/chain/txindex_test.go
deleted file mode 100644
index bbe109d23..000000000
--- a/chain/txindex_test.go
+++ /dev/null
@@ -1,84 +0,0 @@
-/*
- * Copyright 2018 The CovenantSQL Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package chain
-
-import (
-	"reflect"
-	"testing"
-
-	ci "github.com/CovenantSQL/CovenantSQL/chain/interfaces"
-	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
-)
-
-func TestTxIndex(t *testing.T) {
-	var (
-		ti                 = NewTxIndex()
-		otx ci.Transaction = newRandomDemoTxImpl()
-	)
-	// Test operations: Get -> Put -> Get -> Del -> Get
-	if ok := ti.HasTx(otx.GetIndexKey()); ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if _, ok := ti.LoadTx(otx.GetIndexKey()); ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if ok := ti.SetBlock(otx.GetIndexKey(), hash.Hash{}); ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if err := ti.CheckTxState(otx.GetIndexKey()); err != ErrUnknownTx {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-	ti.StoreTx(otx)
-	if ok := ti.HasTx(otx.GetIndexKey()); !ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if xtx, ok := ti.LoadTx(otx.GetIndexKey()); !ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	} else if !reflect.DeepEqual(otx, xtx) {
-		t.Fatalf("Unexpected result:\n\torigin = %v\n\toutput = %v", otx, xtx)
-	}
-	if err := ti.CheckTxState(otx.GetIndexKey()); err != nil {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-	if ok := ti.SetBlock(otx.GetIndexKey(), hash.Hash{}); !ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if err := ti.CheckTxState(otx.GetIndexKey()); err != ErrDuplicateTx {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-	if ok := ti.ResetBlock(otx.GetIndexKey()); !ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if txes := ti.FetchUnpackedTxes(); len(txes) != 1 {
-		t.Fatalf("Unexpected query result: %v", txes)
-	} else if !reflect.DeepEqual(otx, txes[0]) {
-		t.Fatalf("Unexpected result:\n\torigin = %v\n\toutput = %v", otx, txes[0])
-	}
-	ti.DelTx(otx.GetIndexKey())
-	if ok := ti.HasTx(otx.GetIndexKey()); ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if _, ok := ti.LoadTx(otx.GetIndexKey()); ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if ok := ti.SetBlock(otx.GetIndexKey(), hash.Hash{}); ok {
-		t.Fatalf("Unexpected query result: %v", ok)
-	}
-	if err := ti.CheckTxState(otx.GetIndexKey()); err != ErrUnknownTx {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-}
diff --git a/chain/xxx_gen_test.go b/chain/xxx_gen_test.go
deleted file mode 100644
index ed7deaa59..000000000
--- a/chain/xxx_gen_test.go
+++ /dev/null
@@ -1,31 +0,0 @@
-package chain
-
-// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
-
-import (
-	hsp "github.com/CovenantSQL/HashStablePack/marshalhash"
-)
-
-// MarshalHash marshals for hash
-func (z *DemoHeader) MarshalHash() (o []byte, err error) {
-	var b []byte
-	o = hsp.Require(b, z.Msgsize())
-	// map header, size 3
-	o = append(o, 0x83, 0x83)
-	if oTemp, err := z.DatabaseID.MarshalHash(); err != nil {
-		return nil, err
-	} else {
-		o = hsp.AppendBytes(o, oTemp)
-	}
-	o = append(o, 0x83)
-	o = hsp.AppendTime(o, z.Timestamp)
-	o = append(o, 0x83)
-	o = hsp.AppendUint32(o, z.SequenceID)
-	return
-}
-
-// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
-func (z *DemoHeader) Msgsize() (s int) {
-	s = 1 + 11 + z.DatabaseID.Msgsize() + 10 + hsp.TimeSize + 11 + hsp.Uint32Size
-	return
-}
diff --git a/chain/xxx_test.go b/chain/xxx_test.go
deleted file mode 100644
index 80c28b153..000000000
--- a/chain/xxx_test.go
+++ /dev/null
@@ -1,163 +0,0 @@
-/*
- * Copyright 2018 The CovenantSQL Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package chain
-
-import (
-	"io/ioutil"
-	"math/rand"
-	"os"
-	"testing"
-	"time"
-
-	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
-	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
-	"github.com/CovenantSQL/CovenantSQL/proto"
-	"github.com/CovenantSQL/CovenantSQL/utils"
-)
-
-var (
-	testDataDir string
-	testPrivKey *asymmetric.PrivateKey
-	testPubKey  *asymmetric.PublicKey
-)
-
-func createRandomString(offset, length int) string {
-	buff := make([]byte, rand.Intn(length)+offset)
-	rand.Read(buff)
-	for i, v := range buff {
-		buff[i] = v%(0x7f-0x20) + 0x20
-	}
-	return string(buff)
-}
-
-type DemoHeader struct {
-	DatabaseID proto.DatabaseID
-	SequenceID uint32
-	Timestamp  time.Time
-}
-
-type DemoTxImpl struct {
-	DemoHeader
-	HeaderHash hash.Hash
-	Signee     *asymmetric.PublicKey
-	Signature  *asymmetric.Signature
-}
-
-func newRandomDemoTxImpl() (i *DemoTxImpl) {
-	header := DemoHeader{
-		DatabaseID: proto.DatabaseID(createRandomString(10, 10)),
-		SequenceID: rand.Uint32(),
-		Timestamp:  time.Now().UTC(),
-	}
-
-	enc, err := header.MarshalHash()
-	if err != nil {
-		panic(err)
-	}
-
-	hh := hash.HashH(enc)
-	sig, err := testPrivKey.Sign(hh[:])
-	if err != nil {
-		panic(err)
-	}
-
-	i = &DemoTxImpl{
-		DemoHeader: header,
-		HeaderHash: hh,
-		Signee:     testPubKey,
-		Signature:  sig,
-	}
-	return
-}
-
-func (i *DemoTxImpl) Serialize() (enc []byte, err error) {
-	if b, err := utils.EncodeMsgPack(i); err == nil {
-		enc = b.Bytes()
-	}
-	return
-}
-
-func (i *DemoTxImpl) Deserialize(enc []byte) error {
-	return utils.DecodeMsgPack(enc, i)
-}
-
-func (i *DemoTxImpl) GetDatabaseID() *proto.DatabaseID {
-	return &i.DatabaseID
-}
-
-func (i *DemoTxImpl) GetHash() hash.Hash {
-	return i.HeaderHash
-}
-
-func (i *DemoTxImpl) GetIndexKey() interface{} {
-	return i.HeaderHash
-}
-
-func (i *DemoTxImpl) GetPersistenceKey() []byte {
-	return i.HeaderHash[:]
-}
-
-func (i *DemoTxImpl) GetSequenceID() uint32 {
-	return i.SequenceID
-}
-
-func (i *DemoTxImpl) GetTime() time.Time {
-	return i.Timestamp
-}
-
-func (i *DemoTxImpl) Verify() (err error) {
-	var enc []byte
-	if enc, err = i.DemoHeader.MarshalHash(); err != nil {
-		return
-	} else if h := hash.THashH(enc); !i.HeaderHash.IsEqual(&h) {
-		return
-	} else if !i.Signature.Verify(h[:], i.Signee) {
-		return
-	}
-	return
-}
-
-func setup() {
-	// Setup RNG
-	rand.Seed(time.Now().UnixNano())
-
-	var err error
-	// Create temp directory
-	testDataDir, err = ioutil.TempDir("", "covenantsql")
-	if err != nil {
-		panic(err)
-	}
-	// Create key pair for test
-	testPrivKey, testPubKey, err = asymmetric.GenSecp256k1KeyPair()
-	if err != nil {
-		panic(err)
-	}
-}
-
-func teardown() {
-	if err := os.RemoveAll(testDataDir); err != nil {
-		panic(err)
-	}
-}
-
-func TestMain(m *testing.M) {
-	os.Exit(func() int {
-		setup()
-		defer teardown()
-		return m.Run()
-	}())
-}
diff --git a/chainbus/bus.go b/chainbus/bus.go
new file mode 100644
index 000000000..e2bcfebec
--- /dev/null
+++ b/chainbus/bus.go
@@ -0,0 +1,225 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package chainbus
+
+import (
+	"fmt"
+	"reflect"
+	"sync"
+
+	bi "github.com/CovenantSQL/CovenantSQL/blockproducer/interfaces"
+)
+
+// ChainSuber defines subscribing-related bus behavior
+type ChainSuber interface {
+	Subscribe(topic bi.TransactionType, handler interface{}) error
+	SubscribeAsync(topic bi.TransactionType, handler interface{}, transactional bool) error
+	SubscribeOnce(topic bi.TransactionType, handler interface{}) error
+	SubscribeOnceAsync(topic bi.TransactionType, handler interface{}) error
+	Unsubscribe(topic bi.TransactionType, handler interface{}) error
+}
+
+// ChainPuber defines publishing-related bus behavior
+type ChainPuber interface {
+	Publish(topic bi.TransactionType, args ...interface{})
+}
+
+// BusController defines bus control behavior (checking handler's presence, synchronization)
+type BusController interface {
+	HasCallback(topic bi.TransactionType) bool
+	WaitAsync()
+}
+
+// Bus englobes global (subscribe, publish, control) bus behavior
+type Bus interface {
+	BusController
+	ChainSuber
+	ChainPuber
+}
+
+// ChainBus - box for handlers and callbacks.
+type ChainBus struct {
+	handlers map[bi.TransactionType][]*eventHandler
+	lock     sync.Mutex // a lock for the map
+	wg       sync.WaitGroup
+}
+
+type eventHandler struct {
+	callBack      reflect.Value
+	flagOnce      bool
+	async         bool
+	transactional bool
+	sync.Mutex    // lock for an event handler - useful for running async callbacks serially
+}
+
+// New returns new ChainBus with empty handlers.
+func New() Bus {
+	b := &ChainBus{
+		make(map[bi.TransactionType][]*eventHandler),
+		sync.Mutex{},
+		sync.WaitGroup{},
+	}
+	return b
+}
+
+// doSubscribe handles the subscription logic and is utilized by the public Subscribe functions
+func (bus *ChainBus) doSubscribe(topic bi.TransactionType, fn interface{}, handler *eventHandler) error {
+	bus.lock.Lock()
+	defer bus.lock.Unlock()
+	if !(reflect.TypeOf(fn).Kind() == reflect.Func) {
+		return fmt.Errorf("%s is not of type reflect.Func", reflect.TypeOf(fn).Kind())
+	}
+	bus.handlers[topic] = append(bus.handlers[topic], handler)
+	return nil
+}
+
+// Subscribe subscribes to a topic.
+// Returns error if `fn` is not a function.
+func (bus *ChainBus) Subscribe(topic bi.TransactionType, fn interface{}) error {
+	return bus.doSubscribe(topic, fn, &eventHandler{
+		reflect.ValueOf(fn), false, false, false, sync.Mutex{},
+	})
+}
+
+// SubscribeAsync subscribes to a topic with an asynchronous callback
+// Transactional determines whether subsequent callbacks for a topic are
+// run serially (true) or concurrently (false)
+// Returns error if `fn` is not a function.
+func (bus *ChainBus) SubscribeAsync(topic bi.TransactionType, fn interface{}, transactional bool) error {
+	return bus.doSubscribe(topic, fn, &eventHandler{
+		reflect.ValueOf(fn), false, true, transactional, sync.Mutex{},
+	})
+}
+
+// SubscribeOnce subscribes to a topic once. Handler will be removed after executing.
+// Returns error if `fn` is not a function.
+func (bus *ChainBus) SubscribeOnce(topic bi.TransactionType, fn interface{}) error {
+	return bus.doSubscribe(topic, fn, &eventHandler{
+		reflect.ValueOf(fn), true, false, false, sync.Mutex{},
+	})
+}
+
+// SubscribeOnceAsync subscribes to a topic once with an asynchronous callback
+// Handler will be removed after executing.
+// Returns error if `fn` is not a function.
+func (bus *ChainBus) SubscribeOnceAsync(topic bi.TransactionType, fn interface{}) error {
+	return bus.doSubscribe(topic, fn, &eventHandler{
+		reflect.ValueOf(fn), true, true, false, sync.Mutex{},
+	})
+}
+
+// HasCallback returns true if exists any callback subscribed to the topic.
+func (bus *ChainBus) HasCallback(topic bi.TransactionType) bool {
+	bus.lock.Lock()
+	defer bus.lock.Unlock()
+	_, ok := bus.handlers[topic]
+	if ok {
+		return len(bus.handlers[topic]) > 0
+	}
+	return false
+}
+
+// Unsubscribe removes callback defined for a topic.
+// Returns error if there are no callbacks subscribed to the topic.
+func (bus *ChainBus) Unsubscribe(topic bi.TransactionType, handler interface{}) error {
+	bus.lock.Lock()
+	defer bus.lock.Unlock()
+	if _, ok := bus.handlers[topic]; ok && len(bus.handlers[topic]) > 0 {
+		bus.removeHandler(topic, bus.findHandlerIdx(topic, reflect.ValueOf(handler)))
+		return nil
+	}
+	return fmt.Errorf("topic %s doesn't exist", topic)
+}
+
+// Publish executes callback defined for a topic. Any additional argument will be transferred to the callback.
+func (bus *ChainBus) Publish(topic bi.TransactionType, args ...interface{}) {
+	bus.lock.Lock() // will unlock if handler is not found or always after setUpPublish
+	defer bus.lock.Unlock()
+	if handlers, ok := bus.handlers[topic]; ok && 0 < len(handlers) {
+		// Handlers slice may be changed by removeHandler and Unsubscribe during iteration,
+		// so make a copy and iterate the copied slice.
+		copyHandlers := make([]*eventHandler, 0, len(handlers))
+		copyHandlers = append(copyHandlers, handlers...)
+		for i, handler := range copyHandlers {
+			if handler.flagOnce {
+				bus.removeHandler(topic, i)
+			}
+			if !handler.async {
+				bus.doPublish(handler, topic, args...)
+			} else {
+				bus.wg.Add(1)
+				if handler.transactional {
+					handler.Lock()
+				}
+				go bus.doPublishAsync(handler, topic, args...)
+			}
+		}
+	}
+}
+
+func (bus *ChainBus) doPublish(handler *eventHandler, topic bi.TransactionType, args ...interface{}) {
+	passedArguments := bus.setUpPublish(topic, args...)
+	handler.callBack.Call(passedArguments)
+}
+
+func (bus *ChainBus) doPublishAsync(handler *eventHandler, topic bi.TransactionType, args ...interface{}) {
+	defer bus.wg.Done()
+	if handler.transactional {
+		defer handler.Unlock()
+	}
+	bus.doPublish(handler, topic, args...)
+}
+
+func (bus *ChainBus) removeHandler(topic bi.TransactionType, idx int) {
+	if _, ok := bus.handlers[topic]; !ok {
+		return
+	}
+	l := len(bus.handlers[topic])
+
+	if !(0 <= idx && idx < l) {
+		return
+	}
+
+	copy(bus.handlers[topic][idx:], bus.handlers[topic][idx+1:])
+	bus.handlers[topic][l-1] = nil // or the zero value of T
+	bus.handlers[topic] = bus.handlers[topic][:l-1]
+}
+
+func (bus *ChainBus) findHandlerIdx(topic bi.TransactionType, callback reflect.Value) int {
+	if _, ok := bus.handlers[topic]; ok {
+		for idx, handler := range bus.handlers[topic] {
+			if handler.callBack == callback {
+				return idx
+			}
+		}
+	}
+	return -1
+}
+
+func (bus *ChainBus) setUpPublish(topic bi.TransactionType, args ...interface{}) []reflect.Value {
+
+	passedArguments := make([]reflect.Value, 0)
+	for _, arg := range args {
+		passedArguments = append(passedArguments, reflect.ValueOf(arg))
+	}
+	return passedArguments
+}
+
+// WaitAsync waits for all async callbacks to complete
+func (bus *ChainBus) WaitAsync() {
+	bus.wg.Wait()
+}
diff --git a/chainbus/bus_test.go b/chainbus/bus_test.go
new file mode 100644
index 000000000..552bc8dcc
--- /dev/null
+++ b/chainbus/bus_test.go
@@ -0,0 +1,175 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package chainbus
+
+import (
+	"sync/atomic"
+	"testing"
+	"time"
+
+	bi "github.com/CovenantSQL/CovenantSQL/blockproducer/interfaces"
+)
+
+func TestNew(t *testing.T) {
+	bus := New()
+	if bus == nil {
+		t.Log("New EventBus not created!")
+		t.Fail()
+	}
+}
+
+func TestHasCallback(t *testing.T) {
+	bus := New()
+	bus.Subscribe(bi.TransactionType(1), func() {})
+	if bus.HasCallback(bi.TransactionType(2)) {
+		t.Fail()
+	}
+	if !bus.HasCallback(bi.TransactionType(1)) {
+		t.Fail()
+	}
+}
+
+func TestSubscribe(t *testing.T) {
+	bus := New()
+	if bus.Subscribe(bi.TransactionType(1), func() {}) != nil {
+		t.Fail()
+	}
+	if bus.Subscribe(bi.TransactionType(1), "String") == nil {
+		t.Fail()
+	}
+}
+
+func TestSubscribeOnce(t *testing.T) {
+	bus := New()
+	if bus.SubscribeOnce(bi.TransactionType(1), func() {}) != nil {
+		t.Fail()
+	}
+	if bus.SubscribeOnce(bi.TransactionType(1), "String") == nil {
+		t.Fail()
+	}
+}
+
+func TestSubscribeOnceAndManySubscribe(t *testing.T) {
+	bus := New()
+	event := bi.TransactionType(1)
+	flag := 0
+	fn := func() { flag++ }
+	bus.SubscribeOnce(event, fn)
+	bus.Subscribe(event, fn)
+	bus.Subscribe(event, fn)
+	bus.Publish(event)
+
+	if flag != 3 {
+		t.Fail()
+	}
+}
+
+func TestUnsubscribe(t *testing.T) {
+	bus := New()
+	handler := func() {}
+	bus.Subscribe(bi.TransactionType(1), handler)
+	if bus.Unsubscribe(bi.TransactionType(1), handler) != nil {
+		t.Fail()
+	}
+	if bus.Unsubscribe(bi.TransactionType(1), handler) == nil {
+		t.Fail()
+	}
+}
+
+func TestPublish(t *testing.T) {
+	bus := New()
+	bus.Subscribe(bi.TransactionType(1), func(a int, b int) {
+		if a != b {
+			t.Fail()
+		}
+	})
+	bus.Publish(bi.TransactionType(1), 10, 10)
+}
+
+func TestSubcribeOnceAsync(t *testing.T) {
+	results := make([]int, 0)
+
+	bus := New()
+	bus.SubscribeOnceAsync(bi.TransactionType(1), func(a int, out *[]int) {
+		*out = append(*out, a)
+	})
+
+	bus.Publish(bi.TransactionType(1), 10, &results)
+	bus.Publish(bi.TransactionType(1), 10, &results)
+
+	bus.WaitAsync()
+
+	if len(results) != 1 {
+		t.Fail()
+	}
+
+	if bus.HasCallback(bi.TransactionType(1)) {
+		t.Fail()
+	}
+}
+
+func TestSubscribeAsyncTransactional(t *testing.T) {
+	results := make([]int, 0)
+
+	bus := New()
+	bus.SubscribeAsync(bi.TransactionType(1), func(a int, out *[]int, dur string) {
+		sleep, _ := time.ParseDuration(dur)
+		time.Sleep(sleep)
+		*out = append(*out, a)
+	}, true)
+
+	bus.Publish(bi.TransactionType(1), 1, &results, "1s")
+	bus.Publish(bi.TransactionType(1), 2, &results, "0s")
+
+	bus.WaitAsync()
+
+	if len(results) != 2 {
+		t.Fail()
+	}
+
+	if results[0] != 1 || results[1] != 2 {
+		t.Fail()
+	}
+}
+
+func TestSubscribeAsync(t *testing.T) {
+	results := make(chan int)
+
+	bus := New()
+	bus.SubscribeAsync(bi.TransactionType(1), func(a int, out chan<- int) {
+		out <- a
+	}, false)
+
+	bus.Publish(bi.TransactionType(1), 1, results)
+	bus.Publish(bi.TransactionType(1), 2, results)
+
+	var numResults int32
+
+	go func() {
+		for range results {
+			atomic.AddInt32(&numResults, 1)
+		}
+	}()
+
+	bus.WaitAsync()
+
+	time.Sleep(10 * time.Millisecond)
+
+	if atomic.LoadInt32(&numResults) != 2 {
+		t.Fail()
+	}
+}
diff --git a/chainbus/doc.go b/chainbus/doc.go
new file mode 100644
index 000000000..d606ba5bb
--- /dev/null
+++ b/chainbus/doc.go
@@ -0,0 +1,39 @@
+//The MIT License (MIT)
+//
+//Copyright (c) 2014 Alex Saskevich
+//
+//Permission is hereby granted, free of charge, to any person obtaining a copy
+//of this software and associated documentation files (the "Software"), to deal
+//in the Software without restriction, including without limitation the rights
+//to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//copies of the Software, and to permit persons to whom the Software is
+//furnished to do so, subject to the following conditions:
+//
+//The above copyright notice and this permission notice shall be included in all
+//copies or substantial portions of the Software.
+//
+//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//SOFTWARE.
+
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package chainbus
diff --git a/client/conn.go b/client/conn.go
index 449a304fe..eeec4d1db 100644
--- a/client/conn.go
+++ b/client/conn.go
@@ -29,19 +29,19 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 )
 
 // conn implements an interface sql.Conn.
 type conn struct {
 	dbID proto.DatabaseID
 
-	queries     []wt.Query
+	queries     []types.Query
 	localNodeID proto.NodeID
 	privKey     *asymmetric.PrivateKey
 
-	ackCh         chan *wt.Ack
+	ackCh         chan *types.Ack
 	inTransaction bool
 	closed        int32
 	pCaller       *rpc.PersistentCaller
@@ -64,15 +64,17 @@ func newConn(cfg *Config) (c *conn, err error) {
 		dbID:        proto.DatabaseID(cfg.DatabaseID),
 		localNodeID: localNodeID,
 		privKey:     privKey,
-		queries:     make([]wt.Query, 0),
+		queries:     make([]types.Query, 0),
 	}
 
+	var peers *proto.Peers
 	// get peers from BP
-	if _, err = cacheGetPeers(c.dbID, c.privKey); err != nil {
+	if peers, err = cacheGetPeers(c.dbID, c.privKey); err != nil {
 		log.WithError(err).Error("cacheGetPeers failed")
 		c = nil
 		return
 	}
+	c.pCaller = rpc.NewPersistentCaller(peers.Leader)
 
 	err = c.startAckWorkers(2)
 	if err != nil {
@@ -86,7 +88,7 @@ func newConn(cfg *Config) (c *conn, err error) {
 }
 
 func (c *conn) startAckWorkers(workerCount int) (err error) {
-	c.ackCh = make(chan *wt.Ack, workerCount*4)
+	c.ackCh = make(chan *types.Ack, workerCount*4)
 	for i := 0; i < workerCount; i++ {
 		go c.ackWorker()
 	}
@@ -120,7 +122,7 @@ func (c *conn) ackWorker() {
 					continue
 				}
 
-				var ackRes wt.AckResponse
+				var ackRes types.AckResponse
 				// send ack back
 				if err = pc.Call(route.DBSAck.String(), ack, &ackRes); err != nil {
 					log.WithError(err).Warning("send ack failed")
@@ -203,7 +205,7 @@ func (c *conn) ExecContext(ctx context.Context, query string, args []driver.Name
 	sq := convertQuery(query, args)
 
 	var affectedRows, lastInsertID int64
-	if affectedRows, lastInsertID, _, err = c.addQuery(wt.WriteQuery, sq); err != nil {
+	if affectedRows, lastInsertID, _, err = c.addQuery(types.WriteQuery, sq); err != nil {
 		return
 	}
 
@@ -224,7 +226,7 @@ func (c *conn) QueryContext(ctx context.Context, query string, args []driver.Nam
 
 	// TODO(xq262144): make use of the ctx argument
 	sq := convertQuery(query, args)
-	_, _, rows, err = c.addQuery(wt.ReadQuery, sq)
+	_, _, rows, err = c.addQuery(types.ReadQuery, sq)
 
 	return
 }
@@ -246,7 +248,7 @@ func (c *conn) Commit() (err error) {
 
 	if len(c.queries) > 0 {
 		// send query
-		if _, _, _, err = c.sendQuery(wt.WriteQuery, c.queries); err != nil {
+		if _, _, _, err = c.sendQuery(types.WriteQuery, c.queries); err != nil {
 			return
 		}
 	}
@@ -276,10 +278,10 @@ func (c *conn) Rollback() error {
 	return nil
 }
 
-func (c *conn) addQuery(queryType wt.QueryType, query *wt.Query) (affectedRows int64, lastInsertID int64, rows driver.Rows, err error) {
+func (c *conn) addQuery(queryType types.QueryType, query *types.Query) (affectedRows int64, lastInsertID int64, rows driver.Rows, err error) {
 	if c.inTransaction {
 		// check query type, enqueue query
-		if queryType == wt.ReadQuery {
+		if queryType == types.ReadQuery {
 			// read query is not supported in transaction
 			err = ErrQueryInTransaction
 			return
@@ -301,10 +303,10 @@ func (c *conn) addQuery(queryType wt.QueryType, query *wt.Query) (affectedRows i
 		"args":    query.Args,
 	}).Debug("execute query")
 
-	return c.sendQuery(queryType, []wt.Query{*query})
+	return c.sendQuery(queryType, []types.Query{*query})
 }
 
-func (c *conn) sendQuery(queryType wt.QueryType, queries []wt.Query) (affectedRows int64, lastInsertID int64, rows driver.Rows, err error) {
+func (c *conn) sendQuery(queryType types.QueryType, queries []types.Query) (affectedRows int64, lastInsertID int64, rows driver.Rows, err error) {
 	var peers *proto.Peers
 	if peers, err = cacheGetPeers(c.dbID, c.privKey); err != nil {
 		return
@@ -326,9 +328,9 @@ func (c *conn) sendQuery(queryType wt.QueryType, queries []wt.Query) (affectedRo
 	}()
 
 	// build request
-	req := &wt.Request{
-		Header: wt.SignedRequestHeader{
-			RequestHeader: wt.RequestHeader{
+	req := &types.Request{
+		Header: types.SignedRequestHeader{
+			RequestHeader: types.RequestHeader{
 				QueryType:    queryType,
 				NodeID:       c.localNodeID,
 				DatabaseID:   c.dbID,
@@ -337,7 +339,7 @@ func (c *conn) sendQuery(queryType wt.QueryType, queries []wt.Query) (affectedRo
 				Timestamp:    getLocalTime(),
 			},
 		},
-		Payload: wt.RequestPayload{
+		Payload: types.RequestPayload{
 			Queries: queries,
 		},
 	}
@@ -346,8 +348,7 @@ func (c *conn) sendQuery(queryType wt.QueryType, queries []wt.Query) (affectedRo
 		return
 	}
 
-	c.pCaller = rpc.NewPersistentCaller(peers.Leader)
-	var response wt.Response
+	var response types.Response
 	if err = c.pCaller.Call(route.DBSQuery.String(), req, &response); err != nil {
 		return
 	}
@@ -358,15 +359,15 @@ func (c *conn) sendQuery(queryType wt.QueryType, queries []wt.Query) (affectedRo
 	}
 	rows = newRows(&response)
 
-	if queryType == wt.WriteQuery {
+	if queryType == types.WriteQuery {
 		affectedRows = response.Header.AffectedRows
 		lastInsertID = response.Header.LastInsertID
 	}
 
 	// build ack
-	c.ackCh <- &wt.Ack{
-		Header: wt.SignedAckHeader{
-			AckHeader: wt.AckHeader{
+	c.ackCh <- &types.Ack{
+		Header: types.SignedAckHeader{
+			AckHeader: types.AckHeader{
 				Response:  response.Header,
 				NodeID:    c.localNodeID,
 				Timestamp: getLocalTime(),
@@ -381,13 +382,13 @@ func getLocalTime() time.Time {
 	return time.Now().UTC()
 }
 
-func convertQuery(query string, args []driver.NamedValue) (sq *wt.Query) {
+func convertQuery(query string, args []driver.NamedValue) (sq *types.Query) {
 	// rebuild args to named args
-	sq = &wt.Query{
+	sq = &types.Query{
 		Pattern: query,
 	}
 
-	sq.Args = make([]wt.NamedArg, len(args))
+	sq.Args = make([]types.NamedArg, len(args))
 
 	for i, v := range args {
 		sq.Args[i].Name = v.Name
diff --git a/client/driver.go b/client/driver.go
index 274c32e70..5a789ae88 100644
--- a/client/driver.go
+++ b/client/driver.go
@@ -33,8 +33,8 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 	"github.com/pkg/errors"
 )
 
@@ -84,7 +84,7 @@ func (d *covenantSQLDriver) Open(dsn string) (conn driver.Conn, err error) {
 }
 
 // ResourceMeta defines new database resources requirement descriptions.
-type ResourceMeta wt.ResourceMeta
+type ResourceMeta types.ResourceMeta
 
 // Init defines init process for client.
 func Init(configFile string, masterKey []byte) (err error) {
@@ -122,12 +122,8 @@ func Create(meta ResourceMeta) (dsn string, err error) {
 		return
 	}
 
-	req := new(bp.CreateDatabaseRequest)
-	req.Header.ResourceMeta = wt.ResourceMeta(meta)
-	if req.Header.Signee, err = kms.GetLocalPublicKey(); err != nil {
-		err = errors.Wrap(err, "get local public key failed")
-		return
-	}
+	req := new(types.CreateDatabaseRequest)
+	req.Header.ResourceMeta = types.ResourceMeta(meta)
 	var privateKey *asymmetric.PrivateKey
 	if privateKey, err = kms.GetLocalPrivateKey(); err != nil {
 		err = errors.Wrap(err, "get local private key failed")
@@ -137,7 +133,7 @@ func Create(meta ResourceMeta) (dsn string, err error) {
 		err = errors.Wrap(err, "sign request failed")
 		return
 	}
-	res := new(bp.CreateDatabaseResponse)
+	res := new(types.CreateDatabaseResponse)
 
 	if err = requestBP(route.BPDBCreateDatabase, req, res); err != nil {
 		err = errors.Wrap(err, "call BPDB.CreateDatabase failed")
@@ -167,11 +163,8 @@ func Drop(dsn string) (err error) {
 		return
 	}
 
-	req := new(bp.DropDatabaseRequest)
+	req := new(types.DropDatabaseRequest)
 	req.Header.DatabaseID = proto.DatabaseID(cfg.DatabaseID)
-	if req.Header.Signee, err = kms.GetLocalPublicKey(); err != nil {
-		return
-	}
 	var privateKey *asymmetric.PrivateKey
 	if privateKey, err = kms.GetLocalPrivateKey(); err != nil {
 		return
@@ -179,7 +172,7 @@ func Drop(dsn string) (err error) {
 	if err = req.Sign(privateKey); err != nil {
 		return
 	}
-	res := new(bp.DropDatabaseResponse)
+	res := new(types.DropDatabaseResponse)
 	err = requestBP(route.BPDBDropDatabase, req, res)
 
 	return
@@ -343,7 +336,7 @@ func cacheGetPeers(dbID proto.DatabaseID, privKey *asymmetric.PrivateKey) (peers
 }
 
 func getPeers(dbID proto.DatabaseID, privKey *asymmetric.PrivateKey) (peers *proto.Peers, err error) {
-	req := new(bp.GetDatabaseRequest)
+	req := new(types.GetDatabaseRequest)
 	req.Header.DatabaseID = dbID
 
 	defer func() {
@@ -357,7 +350,7 @@ func getPeers(dbID proto.DatabaseID, privKey *asymmetric.PrivateKey) (peers *pro
 		return
 	}
 
-	res := new(bp.GetDatabaseResponse)
+	res := new(types.GetDatabaseResponse)
 	if err = requestBP(route.BPDBGetDatabase, req, res); err != nil {
 		return
 	}
diff --git a/client/driver_test.go b/client/driver_test.go
index f412b19f7..018cd9665 100644
--- a/client/driver_test.go
+++ b/client/driver_test.go
@@ -36,6 +36,9 @@ func TestInit(t *testing.T) {
 		stopTestService, confDir, err = startTestService()
 		So(err, ShouldBeNil)
 		defer stopTestService()
+		// already init ed
+		err = Init(filepath.Join(confDir, "config.yaml"), []byte(""))
+		So(err, ShouldNotBeNil)
 		// fake driver not initialized
 		atomic.StoreUint32(&driverInitialized, 0)
 		err = Init(filepath.Join(confDir, "config.yaml"), []byte(""))
diff --git a/client/helper_test.go b/client/helper_test.go
index c8cdead5a..9b4be6670 100644
--- a/client/helper_test.go
+++ b/client/helper_test.go
@@ -38,11 +38,10 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
 	"github.com/CovenantSQL/CovenantSQL/worker"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 )
 
 const (
@@ -57,7 +56,7 @@ var (
 // fake BPDB service
 type stubBPDBService struct{}
 
-func (s *stubBPDBService) CreateDatabase(req *bp.CreateDatabaseRequest, resp *bp.CreateDatabaseResponse) (err error) {
+func (s *stubBPDBService) CreateDatabase(req *types.CreateDatabaseRequest, resp *types.CreateDatabaseResponse) (err error) {
 	if resp.Header.InstanceMeta, err = s.getInstanceMeta(proto.DatabaseID("db")); err != nil {
 		return
 	}
@@ -74,11 +73,11 @@ func (s *stubBPDBService) CreateDatabase(req *bp.CreateDatabaseRequest, resp *bp
 	return
 }
 
-func (s *stubBPDBService) DropDatabase(req *bp.DropDatabaseRequest, resp *bp.DropDatabaseRequest) (err error) {
+func (s *stubBPDBService) DropDatabase(req *types.DropDatabaseRequest, resp *types.DropDatabaseRequest) (err error) {
 	return
 }
 
-func (s *stubBPDBService) GetDatabase(req *bp.GetDatabaseRequest, resp *bp.GetDatabaseResponse) (err error) {
+func (s *stubBPDBService) GetDatabase(req *types.GetDatabaseRequest, resp *types.GetDatabaseResponse) (err error) {
 	if resp.Header.InstanceMeta, err = s.getInstanceMeta(req.Header.DatabaseID); err != nil {
 		return
 	}
@@ -95,8 +94,8 @@ func (s *stubBPDBService) GetDatabase(req *bp.GetDatabaseRequest, resp *bp.GetDa
 	return
 }
 
-func (s *stubBPDBService) GetNodeDatabases(req *wt.InitService, resp *wt.InitServiceResponse) (err error) {
-	resp.Header.Instances = make([]wt.ServiceInstance, 0)
+func (s *stubBPDBService) GetNodeDatabases(req *types.InitService, resp *types.InitServiceResponse) (err error) {
+	resp.Header.Instances = make([]types.ServiceInstance, 0)
 	if resp.Header.Signee, err = kms.GetLocalPublicKey(); err != nil {
 		return
 	}
@@ -110,7 +109,7 @@ func (s *stubBPDBService) GetNodeDatabases(req *wt.InitService, resp *wt.InitSer
 	return
 }
 
-func (s *stubBPDBService) getInstanceMeta(dbID proto.DatabaseID) (instance wt.ServiceInstance, err error) {
+func (s *stubBPDBService) getInstanceMeta(dbID proto.DatabaseID) (instance types.ServiceInstance, err error) {
 	var privKey *asymmetric.PrivateKey
 	if privKey, err = kms.GetLocalPrivateKey(); err != nil {
 		return
@@ -187,10 +186,10 @@ func startTestService() (stopTestService func(), tempDir string, err error) {
 	}
 
 	// add database
-	var req *wt.UpdateService
-	var res wt.UpdateServiceResponse
+	var req *types.UpdateService
+	var res types.UpdateServiceResponse
 	var peers *proto.Peers
-	var block *ct.Block
+	var block *types.Block
 
 	dbID := proto.DatabaseID("db")
 
@@ -203,9 +202,9 @@ func startTestService() (stopTestService func(), tempDir string, err error) {
 	}
 
 	// build create database request
-	req = new(wt.UpdateService)
-	req.Header.Op = wt.CreateDB
-	req.Header.Instance = wt.ServiceInstance{
+	req = new(types.UpdateService)
+	req.Header.Op = types.CreateDB
+	req.Header.Instance = types.ServiceInstance{
 		DatabaseID:   dbID,
 		Peers:        peers,
 		GenesisBlock: block,
@@ -306,7 +305,7 @@ func initNode() (cleanupFunc func(), tempDir string, server *rpc.Server, err err
 }
 
 // copied from sqlchain.xxx_test.
-func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error) {
+func createRandomBlock(parent hash.Hash, isGenesis bool) (b *types.Block, err error) {
 	// Generate key pair
 	priv, pub, err := asymmetric.GenSecp256k1KeyPair()
 
@@ -317,9 +316,9 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 	h := hash.Hash{}
 	rand.Read(h[:])
 
-	b = &ct.Block{
-		SignedHeader: ct.SignedHeader{
-			Header: ct.Header{
+	b = &types.Block{
+		SignedHeader: types.SignedHeader{
+			Header: types.Header{
 				Version:     0x01000000,
 				Producer:    proto.NodeID(h.String()),
 				GenesisHash: rootHash,
@@ -327,12 +326,6 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 				Timestamp:   time.Now().UTC(),
 			},
 		},
-		Queries: make([]*hash.Hash, rand.Intn(10)+10),
-	}
-
-	for i := range b.Queries {
-		b.Queries[i] = new(hash.Hash)
-		rand.Read(b.Queries[i][:])
 	}
 
 	if isGenesis {
diff --git a/client/result_test.go b/client/result_test.go
new file mode 100644
index 000000000..be6975fcc
--- /dev/null
+++ b/client/result_test.go
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package client
+
+import (
+	"testing"
+
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestExecResult(t *testing.T) {
+	Convey("test result", t, func() {
+		r := &execResult{
+			affectedRows: 1,
+			lastInsertID: 2,
+		}
+
+		i, err := r.LastInsertId()
+		So(i, ShouldEqual, 2)
+		So(err, ShouldBeNil)
+		i, err = r.RowsAffected()
+		So(i, ShouldEqual, 1)
+		So(err, ShouldBeNil)
+	})
+}
diff --git a/client/rows.go b/client/rows.go
index cd599f146..dcacc2c06 100644
--- a/client/rows.go
+++ b/client/rows.go
@@ -21,16 +21,16 @@ import (
 	"io"
 	"strings"
 
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 )
 
 type rows struct {
 	columns []string
 	types   []string
-	data    []wt.ResponseRow
+	data    []types.ResponseRow
 }
 
-func newRows(res *wt.Response) *rows {
+func newRows(res *types.Response) *rows {
 	return &rows{
 		columns: res.Payload.Columns,
 		types:   res.Payload.DeclTypes,
diff --git a/client/rows_test.go b/client/rows_test.go
index 80795c7e8..15602b4eb 100644
--- a/client/rows_test.go
+++ b/client/rows_test.go
@@ -15,3 +15,45 @@
  */
 
 package client
+
+import (
+	"database/sql/driver"
+	"io"
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/types"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestRowsStructure(t *testing.T) {
+	Convey("test rows", t, func() {
+		r := newRows(&types.Response{
+			Payload: types.ResponsePayload{
+				Columns: []string{
+					"a",
+				},
+				DeclTypes: []string{
+					"int",
+				},
+				Rows: []types.ResponseRow{
+					{
+						Values: []interface{}{1},
+					},
+				},
+			},
+		})
+		columns := r.Columns()
+		So(columns, ShouldResemble, []string{"a"})
+		So(r.ColumnTypeDatabaseTypeName(0), ShouldEqual, "INT")
+
+		dest := make([]driver.Value, 1)
+		err := r.Next(dest)
+		So(err, ShouldBeNil)
+		So(dest[0], ShouldEqual, 1)
+		err = r.Next(dest)
+		So(err, ShouldEqual, io.EOF)
+		err = r.Close()
+		So(err, ShouldBeNil)
+		So(r.data, ShouldBeNil)
+	})
+}
diff --git a/client/stmt_test.go b/client/stmt_test.go
index 4672a9a92..a3aebb0fa 100644
--- a/client/stmt_test.go
+++ b/client/stmt_test.go
@@ -17,7 +17,10 @@
 package client
 
 import (
+	"context"
 	"database/sql"
+	"database/sql/driver"
+	"fmt"
 	"testing"
 
 	. "github.com/smartystreets/goconvey/convey"
@@ -95,10 +98,84 @@ func TestStmt(t *testing.T) {
 		_, err = stmt.Exec()
 		So(err, ShouldNotBeNil)
 
+		ctx := context.Background()
+		err = ExecuteTx(ctx, db, nil /* txopts */, func(tx *sql.Tx) error {
+			_, err := tx.Exec("insert into test values(?)", 7)
+			if err != nil {
+				return err
+			}
+			_, err = tx.Exec("insert into test values(?)", 8)
+			if err != nil {
+				return err
+			}
+			_, err = tx.Exec("insert into test values(?)", 9)
+			if err != nil {
+				return err
+			}
+			return err
+		})
+		So(err, ShouldBeNil)
+
+		row = db.QueryRow("select count(1) as cnt from test")
+		So(row, ShouldNotBeNil)
+		err = row.Scan(&result)
+		So(err, ShouldBeNil)
+		So(result, ShouldEqual, 6)
+
+		err = ExecuteTx(ctx, db, nil /* txopts */, func(tx *sql.Tx) error {
+			_, err := tx.Exec("insert into test values(?)", 10)
+			if err != nil {
+				return err
+			}
+			_, err = tx.Exec("insert into testNoExist values(?)", 11)
+			if err != nil {
+				return err
+			}
+			_, err = tx.Exec("insert into test values(?)", 12)
+			if err != nil {
+				return err
+			}
+			return err
+		})
+		So(err, ShouldNotBeNil)
+
+		err = ExecuteTx(ctx, db, nil /* txopts */, func(tx *sql.Tx) error {
+			_, err := tx.Exec("insert into test values(?)", 10)
+			if err != nil {
+				return err
+			}
+			return fmt.Errorf("some error")
+		})
+		So(err, ShouldNotBeNil)
+
+		row = db.QueryRow("select count(1) as cnt from test")
+		So(row, ShouldNotBeNil)
+		err = row.Scan(&result)
+		So(err, ShouldBeNil)
+		So(result, ShouldEqual, 6)
+
 		db.Close()
 
 		// prepare on closed
 		_, err = db.Prepare("select * from test")
 		So(err, ShouldNotBeNil)
+
+		err = ExecuteTx(nil, db, nil /* txopts */, func(tx *sql.Tx) error {
+			return nil
+		})
+		So(err, ShouldNotBeNil)
+
+		// closed stmt and old args
+		cs := newStmt(nil, "test query")
+		cs.Close()
+
+		_, err = cs.Query([]driver.Value{1})
+		So(err, ShouldNotBeNil)
+
+		_, err = cs.Exec([]driver.Value{2})
+		err = ExecuteTx(nil, db, nil /* txopts */, func(tx *sql.Tx) error {
+			return nil
+		})
+		So(err, ShouldNotBeNil)
 	})
 }
diff --git a/client/tx.go b/client/tx.go
new file mode 100644
index 000000000..047d1ccfe
--- /dev/null
+++ b/client/tx.go
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2016 The Cockroach Authors.
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package client
+
+import (
+	"context"
+	"database/sql"
+	"database/sql/driver"
+)
+
+// ExecuteTx starts a transaction, and runs fn in it
+func ExecuteTx(
+	ctx context.Context, db *sql.DB, txopts *sql.TxOptions, fn func(*sql.Tx) error,
+) error {
+	// Start a transaction.
+	tx, err := db.BeginTx(ctx, txopts)
+	if err != nil {
+		return err
+	}
+	return ExecuteInTx(tx, func() error { return fn(tx) })
+}
+
+// ExecuteInTx runs fn inside tx which should already have begun.
+func ExecuteInTx(tx driver.Tx, fn func() error) (err error) {
+	err = fn()
+	if err == nil {
+		// Ignore commit errors. The tx has already been committed by RELEASE.
+		err = tx.Commit()
+	} else {
+		// We always need to execute a Rollback() so sql.DB releases the
+		// connection.
+		_ = tx.Rollback()
+	}
+	return
+}
diff --git a/cmd/cql-adapter/storage/covenantsql.go b/cmd/cql-adapter/storage/covenantsql.go
index e32f0a7ad..9750c891c 100644
--- a/cmd/cql-adapter/storage/covenantsql.go
+++ b/cmd/cql-adapter/storage/covenantsql.go
@@ -102,8 +102,10 @@ func (s *CovenantSQLStorage) Exec(dbID string, query string) (affectedRows int64
 	var result sql.Result
 	result, err = conn.Exec(query)
 
-	affectedRows, _ = result.RowsAffected()
-	lastInsertID, _ = result.LastInsertId()
+	if err == nil {
+		affectedRows, _ = result.RowsAffected()
+		lastInsertID, _ = result.LastInsertId()
+	}
 
 	return
 }
diff --git a/cmd/cql-explorer/service.go b/cmd/cql-explorer/service.go
index 0ccda7ff3..d77181285 100644
--- a/cmd/cql-explorer/service.go
+++ b/cmd/cql-explorer/service.go
@@ -215,7 +215,7 @@ func (s *Service) getTxByHash(h *hash.Hash) (tx pi.Transaction, c uint32, height
 			continue
 		}
 
-		if curH := curTx.GetHash(); h.IsEqual(&curH) {
+		if curH := curTx.Hash(); h.IsEqual(&curH) {
 			tx = curTx
 			break
 		}
@@ -367,7 +367,7 @@ func (s *Service) saveTransaction(c uint32, tx pi.Transaction) (err error) {
 		return ErrNilTransaction
 	}
 
-	txHash := tx.GetHash()
+	txHash := tx.Hash()
 
 	var txKey []byte
 
diff --git a/cmd/cql-fuse/block.go b/cmd/cql-fuse/block.go
new file mode 100644
index 000000000..ceb421336
--- /dev/null
+++ b/cmd/cql-fuse/block.go
@@ -0,0 +1,361 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Copyright 2015 The Cockroach Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License. See the AUTHORS file
+// for names of contributors.
+//
+// Author: Marc Berhault (marc@cockroachlabs.com)
+
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
+)
+
+// BlockSize is the size of each data block. It must not
+// change throughout the lifetime of the filesystem.
+const BlockSize = 4 << 10 // 4KB
+
+func min(a, b uint64) uint64 {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+// blockRange describes a range of blocks.
+// If the first and last block are the same, the effective data range
+// will be: [startOffset, lastLength)
+type blockRange struct {
+	start       int    // index of the start block
+	startOffset uint64 // starting offset within the first block
+	startLength uint64 // length of data in first block
+	last        int    // index of the last block
+	lastLength  uint64 // length of the last block
+}
+
+// newBlockRange returns the block range for 'size' bytes from 'from'.
+func newBlockRange(from, length uint64) blockRange {
+	end := from + length
+	return blockRange{
+		start:       int(from / BlockSize),
+		startOffset: from % BlockSize,
+		startLength: min(length, BlockSize-(from%BlockSize)),
+		last:        int(end / BlockSize),
+		lastLength:  end % BlockSize,
+	}
+}
+
+// shrink resizes the data to a smaller length.
+// Requirement: from > to.
+// If truncates are done on block boundaries, this is reasonably
+// efficient. However, if truncating in the middle of a block,
+// we need to fetch the block first, truncate it, and write it again.
+func shrink(e sqlExecutor, inodeID, from, to uint64) error {
+	delRange := newBlockRange(to, from-to)
+	deleteFrom := delRange.start
+
+	if delRange.startOffset > 0 {
+		// We're truncating in the middle of a block, fetch it, truncate its
+		// data, and write it again.
+		// TODO(marc): this would be more efficient if we had LEFT for bytes.
+		data, err := getBlockData(e, inodeID, delRange.start)
+		if err != nil {
+			return err
+		}
+		data = data[:delRange.startOffset]
+		if err := updateBlockData(e, inodeID, delRange.start, data); err != nil {
+			return err
+		}
+		// We don't need to delete this block.
+		deleteFrom++
+	}
+
+	deleteTo := delRange.last
+	if delRange.lastLength == 0 {
+		// The last block did not previously exist.
+		deleteTo--
+	}
+	if deleteTo < deleteFrom {
+		return nil
+	}
+
+	// There is something to delete.
+	// TODO(marc): would it be better to pass the block IDs?
+	delStmt := `DELETE FROM fs_BLOCK WHERE id = ? AND block >= ?`
+	if _, err := e.Exec(delStmt, inodeID, deleteFrom); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// grow resizes the data to a larger length.
+// Requirement: to > from.
+// If the file ended in a partial block, we fetch it, grow it,
+// and write it back.
+func grow(e sqlExecutor, inodeID, from, to uint64) error {
+	addRange := newBlockRange(from, to-from)
+	insertFrom := addRange.start
+
+	if addRange.startOffset > 0 {
+		// We need to extend the original 'last block'.
+		// Fetch it, grow it, and update it.
+		// TODO(marc): this would be more efficient if we had RPAD for bytes.
+		data, err := getBlockData(e, inodeID, addRange.start)
+		if err != nil {
+			return err
+		}
+		data = append(data, make([]byte, addRange.startLength, addRange.startLength)...)
+		if err := updateBlockData(e, inodeID, addRange.start, data); err != nil {
+			return err
+		}
+		// We don't need to insert this block.
+		insertFrom++
+	}
+
+	insertTo := addRange.last
+	if insertTo < insertFrom {
+		return nil
+	}
+
+	// Build the sql statement and blocks to insert.
+	// We don't share this functionality with 'write' because we can repeat empty blocks.
+	// This would be shorter if we weren't trying to be efficient.
+	// TODO(marc): this would also be better if we supported sparse files.
+	paramStrings := []string{}
+	params := []interface{}{}
+	count := 1 // placeholder count starts at 1.
+	if insertFrom != insertTo {
+		// We have full blocks. Only send a full block once.
+		for i := insertFrom; i < insertTo; i++ {
+			params = append(params, make([]byte, BlockSize, BlockSize))
+		}
+		count++
+	}
+
+	// Go over all blocks that are certainly full.
+	for i := insertFrom; i < insertTo; i++ {
+		paramStrings = append(paramStrings, fmt.Sprintf("(%d, %d, ?)", inodeID, i))
+	}
+
+	// Check the last block.
+	if addRange.lastLength > 0 {
+		// Not empty, write it. It can't be a full block, because we
+		// would have an empty block right after.
+		params = append(params, make([]byte, addRange.lastLength, addRange.lastLength))
+		paramStrings = append(paramStrings, fmt.Sprintf("(%d, %d, ?)",
+			inodeID, addRange.last))
+		count++
+	}
+
+	if len(paramStrings) == 0 {
+		// We had only one block, and it was empty. Nothing do to.
+		return nil
+	}
+
+	insStmt := fmt.Sprintf(`INSERT INTO fs_block VALUES %s`, strings.Join(paramStrings, ","))
+	if _, err := e.Exec(insStmt, params...); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// read returns the data [from, to).
+// Requires: to > from and [to, from) is contained in the file.
+func read(e sqlExecutor, inodeID, from, to uint64) ([]byte, error) {
+	readRange := newBlockRange(from, to-from)
+	end := readRange.last
+	if readRange.lastLength == 0 {
+		end--
+	}
+
+	blockInfos, err := getBlocksBetween(e, inodeID, readRange.start, end)
+	if err != nil {
+		return nil, err
+	}
+	if len(blockInfos) != end-readRange.start+1 {
+		return nil, fmt.Errorf("wrong number of blocks, asked for [%d-%d], got %d back",
+			readRange.start, end, len(blockInfos))
+	}
+
+	if readRange.lastLength != 0 {
+		// We have a last partial block, truncate it.
+		last := len(blockInfos) - 1
+		blockInfos[last].data = blockInfos[last].data[:readRange.lastLength]
+	}
+	blockInfos[0].data = blockInfos[0].data[readRange.startOffset:]
+
+	var data []byte
+	for _, b := range blockInfos {
+		data = append(data, b.data...)
+	}
+
+	return data, nil
+}
+
+// write commits data to the blocks starting at 'offset'
+// Amount of data to write must be non-zero.
+// If offset is greated than 'originalSize', the file is grown first.
+// We always write all or nothing.
+func write(e sqlExecutor, inodeID, originalSize, offset uint64, data []byte) error {
+	if offset > originalSize {
+		diff := offset - originalSize
+		if diff > BlockSize*2 {
+			// we need to grow the file by at least two blocks. Use growing method
+			// which only sends empty blocks once.
+			if err := grow(e, inodeID, originalSize, offset); err != nil {
+				return err
+			}
+			originalSize = offset
+		} else if diff > 0 {
+			// don't grow the file first, just change what we need to write.
+			data = append(make([]byte, diff, diff), data...)
+			offset = originalSize
+		}
+	}
+
+	// Now we know that offset is <= originalSize.
+	writeRange := newBlockRange(offset, uint64(len(data)))
+	writeFrom := writeRange.start
+
+	if writeRange.startOffset > 0 {
+		// We're partially overwriting a block (this includes appending
+		// to the last block): fetch it, grow it, and update it.
+		// TODO(marc): this would be more efficient if we had RPAD for bytes.
+		blockData, err := getBlockData(e, inodeID, writeRange.start)
+		if err != nil {
+			return err
+		}
+		blockData = append(blockData[:writeRange.startOffset], data[:writeRange.startLength]...)
+		data = data[writeRange.startLength:]
+		if err := updateBlockData(e, inodeID, writeRange.start, blockData); err != nil {
+			return err
+		}
+		// We don't need to insert this block.
+		writeFrom++
+	}
+
+	writeTo := writeRange.last
+	if writeRange.lastLength == 0 {
+		// Last block is empty, don't update/insert it.
+		writeTo--
+	}
+	if writeTo < writeFrom {
+		return nil
+	}
+
+	// Figure out last existing block. Needed to tell the difference
+	// between insert and update.
+	lastBlock := int(originalSize / BlockSize)
+	if originalSize%BlockSize == 0 {
+		// Empty blocks do not exist (size=0 -> lastblock=-1).
+		lastBlock--
+	}
+
+	// Process updates first.
+	for i := writeFrom; i <= writeTo; i++ {
+		if i > lastBlock {
+			// We've reached the end of existing blocks, no more UPDATE.
+			break
+		}
+		if len(data) == 0 {
+			panic(fmt.Sprintf("reached end of data, but still have %d blocks to write",
+				writeTo-i))
+		}
+		toWrite := min(BlockSize, uint64(len(data)))
+		blockData := data[:toWrite]
+		data = data[toWrite:]
+		if toWrite != BlockSize {
+			// This is the last block, and it's partial, fetch the original
+			// data from this block and append.
+			// TODO(marc): we could fetch this at the same time as the first
+			// partial block, if any. This would make overwriting in the middle
+			// of the file on non-block boundaries a bit more efficient.
+			origData, err := getBlockData(e, inodeID, i)
+			if err != nil {
+				return err
+			}
+			toWrite = min(toWrite, uint64(len(origData)))
+			blockData = append(blockData, origData[toWrite:]...)
+		}
+		// TODO(marc): is there a way to do batch updates?
+		if err := updateBlockData(e, inodeID, i, blockData); err != nil {
+			return err
+		}
+	}
+
+	if len(data) == 0 {
+		return nil
+	}
+
+	paramStrings := []string{}
+	params := []interface{}{}
+	count := 1 // placeholder count starts at 1.
+
+	for i := lastBlock + 1; i <= writeTo; i++ {
+		if len(data) == 0 {
+			panic(fmt.Sprintf("reached end of data, but still have %d blocks to write",
+				writeTo-i))
+		}
+		toWrite := min(BlockSize, uint64(len(data)))
+		blockData := data[:toWrite]
+		data = data[toWrite:]
+		paramStrings = append(paramStrings, fmt.Sprintf("(%d, %d, ?)",
+			inodeID, i))
+		params = append(params, blockData)
+		count++
+	}
+
+	if len(data) != 0 {
+		panic(fmt.Sprintf("processed all blocks, but still have %d of data to write", len(data)))
+	}
+
+	insStmt := fmt.Sprintf(`INSERT INTO fs_block VALUES %s`, strings.Join(paramStrings, ","))
+	log.Warn(insStmt, params)
+	if _, err := e.Exec(insStmt, params...); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// resize changes the size of the data for the inode with id 'inodeID'
+// from 'from' to 'to'. This may grow or shrink.
+func resizeBlocks(e sqlExecutor, inodeID, from, to uint64) error {
+	if to < from {
+		return shrink(e, inodeID, from, to)
+	} else if to > from {
+		return grow(e, inodeID, from, to)
+	}
+	return nil
+}
diff --git a/cmd/cql-fuse/block_test.go b/cmd/cql-fuse/block_test.go
new file mode 100644
index 000000000..13ec53664
--- /dev/null
+++ b/cmd/cql-fuse/block_test.go
@@ -0,0 +1,540 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Copyright 2015 The Cockroach Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License. See the AUTHORS file
+// for names of contributors.
+//
+// Author: Marc Berhault (marc@cockroachlabs.com)
+
+package main
+
+import (
+	"bytes"
+	"context"
+	"database/sql"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"reflect"
+	"sync"
+	"syscall"
+	"testing"
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/client"
+	"github.com/CovenantSQL/CovenantSQL/utils"
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
+)
+
+var (
+	baseDir        = utils.GetProjectSrcDir()
+	testWorkingDir = FJ(baseDir, "./test/")
+	logDir         = FJ(testWorkingDir, "./log/")
+	db             *sql.DB
+)
+
+var nodeCmds []*utils.CMD
+
+var FJ = filepath.Join
+
+func TestMain(m *testing.M) {
+	os.Exit(func() int {
+		var stop func()
+		db, stop = initTestDB()
+		defer stop()
+		defer db.Close()
+		return m.Run()
+	}())
+}
+
+func startNodes() {
+	ctx := context.Background()
+
+	// wait for ports to be available
+	var err error
+
+	err = utils.WaitForPorts(ctx, "127.0.0.1", []int{
+		6122,
+		6121,
+		6120,
+	}, time.Millisecond*200)
+
+	if err != nil {
+		log.Fatalf("wait for port ready timeout: %v", err)
+	}
+
+	// start 3bps
+	var cmd *utils.CMD
+	if cmd, err = utils.RunCommandNB(
+		FJ(baseDir, "./bin/cqld.test"),
+		[]string{"-config", FJ(testWorkingDir, "./fuse/node_0/config.yaml"),
+			"-test.coverprofile", FJ(baseDir, "./cmd/cql-fuse/leader.cover.out"),
+		},
+		"leader", testWorkingDir, logDir, true,
+	); err == nil {
+		nodeCmds = append(nodeCmds, cmd)
+	} else {
+		log.Errorf("start node failed: %v", err)
+	}
+	if cmd, err = utils.RunCommandNB(
+		FJ(baseDir, "./bin/cqld.test"),
+		[]string{"-config", FJ(testWorkingDir, "./fuse/node_1/config.yaml"),
+			"-test.coverprofile", FJ(baseDir, "./cmd/cql-fuse/follower1.cover.out"),
+		},
+		"follower1", testWorkingDir, logDir, false,
+	); err == nil {
+		nodeCmds = append(nodeCmds, cmd)
+	} else {
+		log.Errorf("start node failed: %v", err)
+	}
+	if cmd, err = utils.RunCommandNB(
+		FJ(baseDir, "./bin/cqld.test"),
+		[]string{"-config", FJ(testWorkingDir, "./fuse/node_2/config.yaml"),
+			"-test.coverprofile", FJ(baseDir, "./cmd/cql-fuse/follower2.cover.out"),
+		},
+		"follower2", testWorkingDir, logDir, false,
+	); err == nil {
+		nodeCmds = append(nodeCmds, cmd)
+	} else {
+		log.Errorf("start node failed: %v", err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*30)
+	defer cancel()
+	err = utils.WaitToConnect(ctx, "127.0.0.1", []int{
+		6122,
+		6121,
+		6120,
+	}, time.Second)
+
+	if err != nil {
+		log.Fatalf("wait for port ready timeout: %v", err)
+	}
+
+	ctx, cancel = context.WithTimeout(context.Background(), time.Second*30)
+	defer cancel()
+	err = utils.WaitForPorts(ctx, "127.0.0.1", []int{
+		3144,
+		3145,
+		3146,
+	}, time.Millisecond*200)
+
+	if err != nil {
+		log.Fatalf("wait for port ready timeout: %v", err)
+	}
+
+	time.Sleep(10 * time.Second)
+
+	// start 3miners
+	os.RemoveAll(FJ(testWorkingDir, "./fuse/node_miner_0/data"))
+	if cmd, err = utils.RunCommandNB(
+		FJ(baseDir, "./bin/cql-minerd.test"),
+		[]string{"-config", FJ(testWorkingDir, "./fuse/node_miner_0/config.yaml"),
+			"-test.coverprofile", FJ(baseDir, "./cmd/cql-fuse/miner0.cover.out"),
+		},
+		"miner0", testWorkingDir, logDir, true,
+	); err == nil {
+		nodeCmds = append(nodeCmds, cmd)
+	} else {
+		log.Errorf("start node failed: %v", err)
+	}
+
+	os.RemoveAll(FJ(testWorkingDir, "./fuse/node_miner_1/data"))
+	if cmd, err = utils.RunCommandNB(
+		FJ(baseDir, "./bin/cql-minerd.test"),
+		[]string{"-config", FJ(testWorkingDir, "./fuse/node_miner_1/config.yaml"),
+			"-test.coverprofile", FJ(baseDir, "./cmd/cql-fuse/miner1.cover.out"),
+		},
+		"miner1", testWorkingDir, logDir, false,
+	); err == nil {
+		nodeCmds = append(nodeCmds, cmd)
+	} else {
+		log.Errorf("start node failed: %v", err)
+	}
+
+	os.RemoveAll(FJ(testWorkingDir, "./fuse/node_miner_2/data"))
+	if cmd, err = utils.RunCommandNB(
+		FJ(baseDir, "./bin/cql-minerd.test"),
+		[]string{"-config", FJ(testWorkingDir, "./fuse/node_miner_2/config.yaml"),
+			"-test.coverprofile", FJ(baseDir, "./cmd/cql-fuse/miner2.cover.out"),
+		},
+		"miner2", testWorkingDir, logDir, false,
+	); err == nil {
+		nodeCmds = append(nodeCmds, cmd)
+	} else {
+		log.Errorf("start node failed: %v", err)
+	}
+}
+
+func stopNodes() {
+	var wg sync.WaitGroup
+	testDir := FJ(testWorkingDir, "./fuse")
+	for _, nodeCmd := range nodeCmds {
+		wg.Add(1)
+		go func(thisCmd *utils.CMD) {
+			defer wg.Done()
+			thisCmd.Cmd.Process.Signal(syscall.SIGTERM)
+			thisCmd.Cmd.Wait()
+			grepRace := exec.Command("/bin/sh", "-c", "grep -A 50 'DATA RACE' "+thisCmd.LogPath)
+			out, _ := grepRace.Output()
+			if len(out) > 2 {
+				log.Fatalf("DATA RACE in %s :\n%s", thisCmd.Cmd.Path, string(out))
+			}
+		}(nodeCmd)
+	}
+
+	wg.Wait()
+	cmd := exec.Command("/bin/sh", "-c", fmt.Sprintf(`cd %s && find . -name '*.db' -exec rm -vf {} \;`, testDir))
+	cmd.Run()
+	cmd = exec.Command("/bin/sh", "-c", fmt.Sprintf(`cd %s && find . -name '*.db-shm' -exec rm -vf {} \;`, testDir))
+	cmd.Run()
+	cmd = exec.Command("/bin/sh", "-c", fmt.Sprintf(`cd %s && find . -name '*.db-wal' -exec rm -vf {} \;`, testDir))
+	cmd.Run()
+	cmd = exec.Command("/bin/sh", "-c", fmt.Sprintf(`cd %s && find . -name 'db.meta' -exec rm -vf {} \;`, testDir))
+	cmd.Run()
+	cmd = exec.Command("/bin/sh", "-c", fmt.Sprintf(`cd %s && find . -name 'public.keystore' -exec rm -vf {} \;`, testDir))
+	cmd.Run()
+	cmd = exec.Command("/bin/sh", "-c", fmt.Sprintf(`cd %s && find . -name '*.public.keystore' -exec rm -vf {} \;`, testDir))
+	cmd.Run()
+	cmd = exec.Command("/bin/sh", "-c", fmt.Sprintf(`cd %s && find . -name '*.ldb' -exec rm -vrf {} \;`, testDir))
+	cmd.Run()
+}
+
+func initTestDB() (*sql.DB, func()) {
+
+	startNodes()
+	var err error
+
+	time.Sleep(10 * time.Second)
+
+	err = client.Init(FJ(testWorkingDir, "./fuse/node_c/config.yaml"), []byte(""))
+	if err != nil {
+		log.Errorf("init client failed: %v", err)
+		return nil, stopNodes
+	}
+
+	// create
+	dsn, err := client.Create(client.ResourceMeta{Node: 1})
+	if err != nil {
+		log.Errorf("create db failed: %v", err)
+		return nil, stopNodes
+	}
+
+	log.Infof("the created database dsn is %v", dsn)
+
+	db, err := sql.Open("covenantsql", dsn)
+	if err != nil {
+		log.Errorf("open db failed: %v", err)
+		return nil, stopNodes
+	}
+
+	if err := initSchema(db); err != nil {
+		stopNodes()
+		log.Fatal(err)
+	}
+
+	return db, stopNodes
+}
+
+func getAllBlocks(db *sql.DB, inode uint64) ([]byte, error) {
+	blocks, err := getBlocks(db, inode)
+	if err != nil {
+		return nil, err
+	}
+	num := len(blocks)
+	var data []byte
+	for i, b := range blocks {
+		if i != b.block {
+			// We can't have missing blocks.
+			return nil, fmt.Errorf("gap in block list, found block %d at index %d", b.block, i)
+		}
+		bl := uint64(len(b.data))
+		if bl == 0 {
+			return nil, fmt.Errorf("empty block found at %d (out of %d blocks)", i, num)
+		}
+		if i != (num-1) && bl != BlockSize {
+			return nil, fmt.Errorf("non-blocksize %d at %d (out of %d blocks)", bl, i, num)
+		}
+		data = append(data, b.data...)
+	}
+	return data, nil
+}
+
+func TestBlockInfo(t *testing.T) {
+	testCases := []struct {
+		start, length uint64
+		expected      blockRange
+	}{
+		{0, 0, blockRange{0, 0, 0, 0, 0}},
+		{0, BlockSize * 4, blockRange{0, 0, BlockSize, 4, 0}},
+		{0, BlockSize*4 + 500, blockRange{0, 0, BlockSize, 4, 500}},
+		{500, BlockSize * 4, blockRange{0, 500, BlockSize - 500, 4, 500}},
+		{BlockSize, BlockSize * 4, blockRange{1, 0, BlockSize, 5, 0}},
+		{BlockSize, 500, blockRange{1, 0, 500, 1, 500}},
+		{500, 1000, blockRange{0, 500, 1000, 0, 1500}},
+	}
+
+	for tcNum, tc := range testCases {
+		actual := newBlockRange(tc.start, tc.length)
+		if !reflect.DeepEqual(actual, tc.expected) {
+			t.Errorf("#%d: expected:\n%+v\ngot:\n%+v", tcNum, tc.expected, actual)
+		}
+	}
+}
+
+func tryGrow(db *sql.DB, data []byte, id, newSize uint64) ([]byte, error) {
+	originalSize := uint64(len(data))
+	data = append(data, make([]byte, newSize-originalSize)...)
+	if err := grow(db, id, originalSize, newSize); err != nil {
+		return nil, err
+	}
+	newData, err := getAllBlocks(db, id)
+	if err != nil {
+		return nil, err
+	}
+	if uint64(len(newData)) != newSize {
+		return nil, fmt.Errorf("getAllBlocks lengths don't match: got %d, expected %d", len(newData), newSize)
+	}
+	if !bytes.Equal(data, newData) {
+		return nil, fmt.Errorf("getAllBlocks data doesn't match")
+	}
+
+	if newSize == 0 {
+		return newData, nil
+	}
+
+	// Check the read as well.
+	newData, err = read(db, id, 0, newSize)
+	if err != nil {
+		return nil, err
+	}
+
+	if uint64(len(newData)) != newSize {
+		return nil, fmt.Errorf("read lengths don't match: got %d, expected %d", len(newData), newSize)
+	}
+	if !bytes.Equal(data, newData) {
+		return nil, fmt.Errorf("read data doesn't match")
+	}
+
+	return newData, nil
+}
+
+func tryShrink(db *sql.DB, data []byte, id, newSize uint64) ([]byte, error) {
+	originalSize := uint64(len(data))
+	data = data[:newSize]
+	if err := shrink(db, id, originalSize, newSize); err != nil {
+		return nil, err
+	}
+	newData, err := getAllBlocks(db, id)
+	if err != nil {
+		return nil, err
+	}
+	if uint64(len(newData)) != newSize {
+		return nil, fmt.Errorf("getAllData lengths don't match: got %d, expected %d", len(newData), newSize)
+	}
+	if !bytes.Equal(data, newData) {
+		return nil, fmt.Errorf("getAllData data doesn't match")
+	}
+
+	if newSize == 0 {
+		return newData, nil
+	}
+
+	// Check the read as well.
+	newData, err = read(db, id, 0, newSize)
+	if err != nil {
+		return nil, err
+	}
+
+	if uint64(len(newData)) != newSize {
+		return nil, fmt.Errorf("read lengths don't match: got %d, expected %d", len(newData), newSize)
+	}
+	if !bytes.Equal(data, newData) {
+		return nil, fmt.Errorf("read data doesn't match")
+	}
+
+	return newData, nil
+}
+
+func TestShrinkGrow(t *testing.T) {
+
+	id := uint64(10)
+
+	var err error
+	data := []byte{}
+
+	if data, err = tryGrow(db, data, id, BlockSize*4+500); err != nil {
+		log.Fatal(err)
+	}
+	if data, err = tryGrow(db, data, id, BlockSize*4+600); err != nil {
+		log.Fatal(err)
+	}
+	if data, err = tryGrow(db, data, id, BlockSize*5); err != nil {
+		log.Fatal(err)
+	}
+
+	// Shrink it down to 0.
+	if data, err = tryShrink(db, data, id, 0); err != nil {
+		log.Fatal(err)
+	}
+	if data, err = tryGrow(db, data, id, BlockSize*3+500); err != nil {
+		log.Fatal(err)
+	}
+	if data, err = tryShrink(db, data, id, BlockSize*3+300); err != nil {
+		log.Fatal(err)
+	}
+	if data, err = tryShrink(db, data, id, BlockSize*3); err != nil {
+		log.Fatal(err)
+	}
+	if data, err = tryShrink(db, data, id, 0); err != nil {
+		log.Fatal(err)
+	}
+	if data, err = tryGrow(db, data, id, BlockSize); err != nil {
+		log.Fatal(err)
+	}
+	if data, err = tryShrink(db, data, id, BlockSize-200); err != nil {
+		log.Fatal(err)
+	}
+	if data, err = tryShrink(db, data, id, BlockSize-500); err != nil {
+		log.Fatal(err)
+	}
+	if data, err = tryShrink(db, data, id, 0); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func TestReadWriteBlocks(t *testing.T) {
+
+	id := uint64(10)
+	rng, _ := NewPseudoRand()
+	length := BlockSize*3 + 500
+	part1 := RandBytes(rng, length)
+
+	if err := write(db, id, 0, 0, part1); err != nil {
+		log.Fatal(err)
+	}
+
+	readData, err := read(db, id, 0, uint64(length))
+	if err != nil {
+		log.Fatal(err)
+	}
+	if !bytes.Equal(part1, readData) {
+		t.Errorf("Bytes differ. lengths: %d, expected %d", len(readData), len(part1))
+	}
+
+	verboseData, err := getAllBlocks(db, id)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if !bytes.Equal(verboseData, part1) {
+		t.Errorf("Bytes differ. lengths: %d, expected %d", len(verboseData), len(part1))
+	}
+
+	// Write with hole in the middle.
+	part2 := make([]byte, BlockSize*2+250, BlockSize*2+250)
+	fullData := append(part1, part2...)
+	part3 := RandBytes(rng, BlockSize+123)
+	if err := write(db, id, uint64(len(part1)), uint64(len(fullData)), part3); err != nil {
+		log.Fatal(err)
+	}
+	fullData = append(fullData, part3...)
+	readData, err = read(db, id, 0, uint64(len(fullData)))
+	if err != nil {
+		log.Fatal(err)
+	}
+	if !bytes.Equal(fullData, readData) {
+		t.Errorf("Bytes differ. lengths: %d, expected %d", len(readData), len(fullData))
+	}
+
+	verboseData, err = getAllBlocks(db, id)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if !bytes.Equal(verboseData, fullData) {
+		t.Errorf("Bytes differ. lengths: %d, expected %d", len(verboseData), len(fullData))
+	}
+
+	// Now write into the middle of the file.
+	part2 = RandBytes(rng, len(part2))
+	if err := write(db, id, uint64(len(fullData)), uint64(len(part1)), part2); err != nil {
+		log.Fatal(err)
+	}
+	fullData = append(part1, part2...)
+	fullData = append(fullData, part3...)
+	readData, err = read(db, id, 0, uint64(len(fullData)))
+	if err != nil {
+		log.Fatal(err)
+	}
+	if !bytes.Equal(fullData, readData) {
+		t.Errorf("Bytes differ. lengths: %d, expected %d", len(readData), len(fullData))
+	}
+
+	verboseData, err = getAllBlocks(db, id)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if !bytes.Equal(verboseData, fullData) {
+		t.Errorf("Bytes differ. lengths: %d, expected %d", len(verboseData), len(fullData))
+	}
+
+	// New file.
+	id2 := uint64(20)
+	if err := write(db, id2, 0, 0, []byte("1")); err != nil {
+		log.Fatal(err)
+	}
+	readData, err = read(db, id2, 0, 1)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if string(readData) != "1" {
+		log.Fatalf("mismatch: %s", readData)
+	}
+
+	if err := write(db, id2, 1, 0, []byte("22")); err != nil {
+		log.Fatal(err)
+	}
+	readData, err = read(db, id2, 0, 2)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if string(readData) != "22" {
+		log.Fatalf("mismatch: %s", readData)
+	}
+
+	id3 := uint64(30)
+	part1 = RandBytes(rng, BlockSize)
+	// Write 5 blocks.
+	var offset uint64
+	for i := 0; i < 5; i++ {
+		if err := write(db, id3, offset, offset, part1); err != nil {
+			log.Fatal(err)
+		}
+		offset += BlockSize
+	}
+}
diff --git a/cmd/cql-fuse/fs.go b/cmd/cql-fuse/fs.go
new file mode 100644
index 000000000..82d9e1166
--- /dev/null
+++ b/cmd/cql-fuse/fs.go
@@ -0,0 +1,319 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Copyright 2015 The Cockroach Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License. See the AUTHORS file
+// for names of contributors.
+//
+// Author: Marc Berhault (marc@cockroachlabs.com)
+
+package main
+
+import (
+	"context"
+	"database/sql"
+	"os"
+	"syscall"
+	"time"
+
+	"bazil.org/fuse"
+	"bazil.org/fuse/fs"
+	"github.com/CovenantSQL/CovenantSQL/client"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
+)
+
+const rootNodeID = 1
+
+const (
+	fsSchema = `
+CREATE TABLE IF NOT EXISTS fs_namespace (
+  parentID INT,
+  name     STRING,
+  id       INT,
+  PRIMARY KEY (parentID, name)
+);
+
+CREATE TABLE IF NOT EXISTS fs_inode (
+  id    INT PRIMARY KEY,
+  inode STRING
+);
+
+CREATE TABLE IF NOT EXISTS fs_block (
+  id    INT,
+  block INT,
+  data  BYTES,
+  PRIMARY KEY (id, block)
+);
+`
+)
+
+var _ fs.FS = &CFS{}               // Root
+var _ fs.FSInodeGenerator = &CFS{} // GenerateInode
+
+// CFS implements a filesystem on top of cockroach.
+type CFS struct {
+	db *sql.DB
+}
+
+func initSchema(db *sql.DB) error {
+	_, err := db.Exec(fsSchema)
+	return err
+}
+
+// create inserts a new node.
+// parentID: inode ID of the parent directory.
+// name: name of the new node
+// node: new node
+func (cfs CFS) create(ctx context.Context, parentID uint64, name string, node *Node) error {
+	inode := node.toJSON()
+	const insertNode = `INSERT INTO fs_inode VALUES (?, ?)`
+	const insertNamespace = `INSERT INTO fs_namespace VALUES (?, ?, ?)`
+
+	err := client.ExecuteTx(ctx, cfs.db, nil /* txopts */, func(tx *sql.Tx) error {
+		if _, err := tx.Exec(insertNode, node.ID, inode); err != nil {
+			return err
+		}
+		if _, err := tx.Exec(insertNamespace, parentID, name, node.ID); err != nil {
+			return err
+		}
+		return nil
+	})
+	return err
+}
+
+// remove removes a node give its name and its parent ID.
+// If 'checkChildren' is true, fails if the node has children.
+func (cfs CFS) remove(ctx context.Context, parentID uint64, name string, checkChildren bool) error {
+	const lookupSQL = `SELECT id FROM fs_namespace WHERE (parentID, name) = (?, ?)`
+	const deleteNamespace = `DELETE FROM fs_namespace WHERE (parentID, name) = (?, ?)`
+	const deleteInode = `DELETE FROM fs_inode WHERE id = ?`
+	const deleteBlock = `DELETE FROM fs_block WHERE id = ?`
+	// Start by looking up the node ID.
+	var id uint64
+	if err := cfs.db.QueryRow(lookupSQL, parentID, name).Scan(&id); err != nil {
+		return err
+	}
+	// Check if there are any children.
+	if checkChildren {
+		if err := checkIsEmpty(cfs.db, id); err != nil {
+			return err
+		}
+	}
+
+	err := client.ExecuteTx(ctx, cfs.db, nil /* txopts */, func(tx *sql.Tx) error {
+		// Delete all entries.
+		if _, err := tx.Exec(deleteNamespace, parentID, name); err != nil {
+			return err
+		}
+		if _, err := tx.Exec(deleteInode, id); err != nil {
+			return err
+		}
+		if _, err := tx.Exec(deleteBlock, id); err != nil {
+			return err
+		}
+		return nil
+	})
+	return err
+}
+
+func (cfs CFS) lookup(parentID uint64, name string) (*Node, error) {
+	return getInode(cfs.db, parentID, name)
+}
+
+// list returns the children of the node with id 'parentID'.
+// Dirent consists of:
+// Inode uint64
+// Type DirentType (optional)
+// Name string
+// TODO(pmattis): lookup all inodes and fill in the type, this will save a Getattr().
+func (cfs CFS) list(parentID uint64) ([]fuse.Dirent, error) {
+	rows, err := cfs.db.Query(`SELECT name, id FROM fs_namespace WHERE parentID = ?`, parentID)
+	if err != nil {
+		return nil, err
+	}
+
+	var results []fuse.Dirent
+	for rows.Next() {
+		dirent := fuse.Dirent{Type: fuse.DT_Unknown}
+		if err := rows.Scan(&dirent.Name, &dirent.Inode); err != nil {
+			return nil, err
+		}
+		results = append(results, dirent)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+
+	return results, nil
+}
+
+// validateRename takes a source and destination node and verifies that
+// a rename can be performed from source to destination.
+// source must not be nil. destination can be.
+func validateRename(e sqlExecutor, source, destination *Node) error {
+	if destination == nil {
+		// No object at destination: good.
+		return nil
+	}
+
+	if source.isDir() {
+		if destination.isDir() {
+			// Both are directories: destination must be empty
+			return checkIsEmpty(e, destination.ID)
+		}
+		// directory -> file: not allowed.
+		return fuse.Errno(syscall.ENOTDIR)
+	}
+
+	// Source is a file.
+	if destination.isDir() {
+		// file -> directory: not allowed.
+		return fuse.Errno(syscall.EISDIR)
+	}
+	return nil
+}
+
+// rename moves 'oldParentID/oldName' to 'newParentID/newName'.
+// If 'newParentID/newName' already exists, it is deleted.
+// See NOTE on node.go:Rename.
+func (cfs CFS) rename(
+	ctx context.Context, oldParentID, newParentID uint64, oldName, newName string,
+) error {
+	if oldParentID == newParentID && oldName == newName {
+		return nil
+	}
+
+	const deleteNamespace = `DELETE FROM fs_namespace WHERE (parentID, name) = (?, ?)`
+	const insertNamespace = `INSERT INTO fs_namespace VALUES (?, ?, ?)`
+	const updateNamespace = `UPDATE fs_namespace SET id = ? WHERE (parentID, name) = (?, ?)`
+	const deleteInode = `DELETE FROM fs_inode WHERE id = ?`
+
+	// Lookup source inode.
+	srcObject, err := getInode(cfs.db, oldParentID, oldName)
+	if err != nil {
+		return err
+	}
+
+	// Lookup destination inode.
+	destObject, err := getInode(cfs.db, newParentID, newName)
+	if err != nil && err != sql.ErrNoRows {
+		return err
+	}
+
+	// Check that the rename is allowed.
+	if err := validateRename(cfs.db, srcObject, destObject); err != nil {
+		return err
+	}
+
+	err = client.ExecuteTx(ctx, cfs.db, nil /* txopts */, func(tx *sql.Tx) error {
+		// At this point we know the following:
+		// - srcObject is not nil
+		// - destObject may be nil. If not, its inode can be deleted.
+		if destObject == nil {
+			// No new object: use INSERT.
+			if _, err := tx.Exec(deleteNamespace, oldParentID, oldName); err != nil {
+				return err
+			}
+
+			if _, err := tx.Exec(insertNamespace, newParentID, newName, srcObject.ID); err != nil {
+				return err
+			}
+		} else {
+			// Destination exists.
+			if _, err := tx.Exec(deleteNamespace, oldParentID, oldName); err != nil {
+				return err
+			}
+
+			if _, err := tx.Exec(updateNamespace, srcObject.ID, newParentID, newName); err != nil {
+				return err
+			}
+
+			if _, err := tx.Exec(deleteInode, destObject.ID); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+	return err
+}
+
+// Root returns the filesystem's root node.
+// This node is special: it has a fixed ID and is not persisted.
+func (cfs CFS) Root() (fs.Node, error) {
+	return &Node{cfs: cfs, ID: rootNodeID, Mode: os.ModeDir | defaultPerms}, nil
+}
+
+// GenerateInode returns a new inode ID.
+func (cfs CFS) GenerateInode(parentInode uint64, name string) uint64 {
+	return cfs.newUniqueID()
+}
+
+func (cfs CFS) newUniqueID() (id uint64) {
+	// cockroach's unique_rowid() Contains time and space (node ID) components
+	// https://www.cockroachlabs.com/docs/stable/sql-faqs.html#\
+	// 		what-are-the-differences-between-uuid-sequences-and-unique_rowid
+	// So, we just build one in the same way.
+	var idRand uint32
+	nodeIDBytes, err := kms.GetLocalNodeIDBytes()
+	if err == nil {
+		idRand = hash.FNVHash32uint(nodeIDBytes)
+	}
+	return uint64(time.Now().UnixNano()) + uint64(idRand)<<32
+	//if err := cfs.db.QueryRow(`SELECT unique_rowid()`).Scan(&id); err != nil {
+	//	panic(err)
+	//}
+	//return
+}
+
+// newFileNode returns a new node struct corresponding to a file.
+func (cfs CFS) newFileNode() *Node {
+	return &Node{
+		cfs:  cfs,
+		ID:   cfs.newUniqueID(),
+		Mode: defaultPerms,
+	}
+}
+
+// newDirNode returns a new node struct corresponding to a directory.
+func (cfs CFS) newDirNode() *Node {
+	return &Node{
+		cfs:  cfs,
+		ID:   cfs.newUniqueID(),
+		Mode: os.ModeDir | defaultPerms,
+	}
+}
+
+// newSymlinkNode returns a new node struct corresponding to a symlink.
+func (cfs CFS) newSymlinkNode() *Node {
+	return &Node{
+		cfs: cfs,
+		ID:  cfs.newUniqueID(),
+		// Symlinks don't have permissions, allow all.
+		Mode: os.ModeSymlink | allPerms,
+	}
+}
diff --git a/cmd/cql-fuse/main.go b/cmd/cql-fuse/main.go
new file mode 100644
index 000000000..6f0f9f4b5
--- /dev/null
+++ b/cmd/cql-fuse/main.go
@@ -0,0 +1,160 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Copyright 2015 The Cockroach Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License. See the AUTHORS file
+// for names of contributors.
+//
+// Author: Marc Berhault (marc@cockroachlabs.com)
+
+// This is a simple fuse filesystem that stores all metadata and data
+// in cockroach.
+//
+// Inode relationships are stored in the `namespace` table, and inodes
+// themselves in the `inode` table.
+//
+// Data blocks are stored in the `block` table, indexed by inode ID
+// and block number.
+//
+// Basic functionality is implemented, including:
+// - mk/rm directory
+// - create/rm files
+// - read/write files
+// - rename
+// - symlinks
+//
+// WARNING: concurrent access on a single mount is fine. However,
+// behavior is undefined (read broken) when mounted more than once at the
+// same time. Specifically, read/writes will not be seen right away and
+// may work on out of date information.
+//
+// One caveat of the implemented features is that handles are not
+// reference counted so if an inode is deleted, all open file descriptors
+// pointing to it become invalid.
+//
+// Some TODOs (definitely not a comprehensive list):
+// - support basic attributes (mode, timestamps)
+// - support other types: hard links
+// - add ref counting (and handle open/release)
+// - sparse files: don't store empty blocks
+// - sparse files 2: keep track of holes
+
+package main
+
+import (
+	"database/sql"
+	"flag"
+	"fmt"
+	"os"
+	"os/signal"
+
+	"github.com/CovenantSQL/CovenantSQL/client"
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
+
+	"bazil.org/fuse"
+	"bazil.org/fuse/fs"
+	_ "bazil.org/fuse/fs/fstestutil"
+)
+
+var usage = func() {
+	fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
+	fmt.Fprintf(os.Stderr, "  %s -config <config> -dsn <dsn> -mount <mountpoint>\n\n", os.Args[0])
+	flag.PrintDefaults()
+}
+
+func main() {
+	var config, dsn, mountPoint, password string
+
+	flag.StringVar(&config, "config", "./conf/config.yaml", "config file path")
+	flag.StringVar(&mountPoint, "mount", "./", "dir to mount")
+	flag.StringVar(&dsn, "dsn", "", "database url")
+	flag.StringVar(&password, "password", "", "master key password for covenantsql")
+	flag.Usage = usage
+	flag.Parse()
+
+	log.SetLevel(log.DebugLevel)
+
+	err := client.Init(config, []byte(password))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	db, err := sql.Open("covenantsql", dsn)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	defer func() { _ = db.Close() }()
+
+	if err := initSchema(db); err != nil {
+		log.Fatal(err)
+	}
+
+	cfs := CFS{db}
+	// Mount filesystem.
+	c, err := fuse.Mount(
+		mountPoint,
+		fuse.FSName("CovenantFS"),
+		fuse.Subtype("CovenantFS"),
+		fuse.LocalVolume(),
+		fuse.VolumeName(""),
+	)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer func() {
+		_ = c.Close()
+	}()
+
+	go func() {
+		sig := make(chan os.Signal, 1)
+		signal.Notify(sig, os.Interrupt)
+		for range sig {
+			if err := fuse.Unmount(mountPoint); err != nil {
+				log.Printf("Signal received, but could not unmount: %s", err)
+			} else {
+				break
+			}
+		}
+	}()
+
+	// Serve root.
+	err = fs.Serve(c, cfs)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// check if the mount process has an error to report
+	<-c.Ready
+	if err := c.MountError; err != nil {
+		log.Fatal(err)
+	}
+}
diff --git a/cmd/cql-fuse/node.go b/cmd/cql-fuse/node.go
new file mode 100644
index 000000000..5ae46a38a
--- /dev/null
+++ b/cmd/cql-fuse/node.go
@@ -0,0 +1,421 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Copyright 2015 The Cockroach Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License. See the AUTHORS file
+// for names of contributors.
+//
+// Author: Marc Berhault (marc@cockroachlabs.com)
+
+package main
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"log"
+	"math"
+	"os"
+	"sync"
+	"syscall"
+
+	"bazil.org/fuse"
+	"bazil.org/fuse/fs"
+
+	"github.com/CovenantSQL/CovenantSQL/client"
+)
+
+var _ fs.Node = &Node{}               // Attr
+var _ fs.NodeSetattrer = &Node{}      // Setattr
+var _ fs.NodeStringLookuper = &Node{} // Lookup
+var _ fs.HandleReadDirAller = &Node{} // HandleReadDirAller
+var _ fs.NodeMkdirer = &Node{}        // Mkdir
+var _ fs.NodeCreater = &Node{}        // Create
+var _ fs.NodeRemover = &Node{}        // Remove
+var _ fs.HandleWriter = &Node{}       // Write
+var _ fs.HandleReader = &Node{}       // Read
+var _ fs.NodeFsyncer = &Node{}        // Fsync
+var _ fs.NodeRenamer = &Node{}        // Rename
+var _ fs.NodeSymlinker = &Node{}      // Symlink
+var _ fs.NodeReadlinker = &Node{}     // Readlink
+
+// Default permissions: we don't have any right now.
+const defaultPerms = 0755
+
+// All permissions.
+const allPerms = 0777
+
+// Maximum file size.
+const maxSize = math.MaxUint64
+
+// Maximum length of a symlink target.
+const maxSymlinkTargetLength = 4096
+
+// Node implements the Node interface.
+// ID, Mode, and SymlinkTarget are currently immutable after node creation.
+// Size (for files only) is protected by mu.
+type Node struct {
+	cfs CFS
+	// ID is a unique ID allocated at node creation time.
+	ID uint64
+	// Used for type only, permissions are ignored.
+	Mode os.FileMode
+	// SymlinkTarget is the path a symlink points to.
+	SymlinkTarget string
+
+	// Other fields to add:
+	// nLinks: number of hard links
+	// openFDs: number of open file descriptors
+	// timestamps (probably just ctime and mtime)
+
+	// Implicit fields:
+	// numBlocks: number of 512b blocks
+	// blocksize: preferred block size
+	// mode bits: permissions
+
+	// For regular files only.
+	// Data blocks are addressed by inode number and offset.
+	// Any op accessing Size and blocks must lock 'mu'.
+	mu   sync.RWMutex
+	Size uint64
+}
+
+// convenience functions to query the mode.
+func (n *Node) isDir() bool {
+	return n.Mode.IsDir()
+}
+
+func (n *Node) isRegular() bool {
+	return n.Mode.IsRegular()
+}
+
+func (n *Node) isSymlink() bool {
+	return n.Mode&os.ModeSymlink != 0
+}
+
+// toJSON returns the json-encoded string for this node.
+func (n *Node) toJSON() string {
+	ret, err := json.Marshal(n)
+	if err != nil {
+		panic(err)
+	}
+	return string(ret)
+}
+
+// Attr fills attr with the standard metadata for the node.
+func (n *Node) Attr(_ context.Context, a *fuse.Attr) error {
+	a.Inode = n.ID
+	a.Mode = n.Mode
+	// Does preferred block size make sense on things other
+	// than regular files?
+	a.BlockSize = BlockSize
+
+	if n.isRegular() {
+		n.mu.RLock()
+		defer n.mu.RUnlock()
+		a.Size = n.Size
+
+		// Blocks is the number of 512 byte blocks, regardless of
+		// filesystem blocksize.
+		a.Blocks = (n.Size + 511) / 512
+	} else if n.isSymlink() {
+		// Symlink: use target name length.
+		a.Size = uint64(len(n.SymlinkTarget))
+	}
+	return nil
+}
+
+// Setattr modifies node metadata. This includes changing the size.
+func (n *Node) Setattr(
+	ctx context.Context, req *fuse.SetattrRequest, resp *fuse.SetattrResponse,
+) error {
+	if !req.Valid.Size() {
+		// We can exit early since only setting the size is implemented.
+		return nil
+	}
+
+	if !n.isRegular() {
+		// Setting the size is only available on regular files.
+		return fuse.Errno(syscall.EINVAL)
+	}
+
+	if req.Size > maxSize {
+		// Too big.
+		return fuse.Errno(syscall.EFBIG)
+	}
+
+	n.mu.Lock()
+	defer n.mu.Unlock()
+
+	if req.Size == n.Size {
+		// Nothing to do.
+		return nil
+	}
+
+	// Store the current size in case we need to rollback.
+	originalSize := n.Size
+
+	// Wrap everything inside a transaction.
+	err := client.ExecuteTx(ctx, n.cfs.db, nil /* txopts */, func(tx *sql.Tx) error {
+		// Resize blocks as needed.
+		if err := resizeBlocks(tx, n.ID, n.Size, req.Size); err != nil {
+			return err
+		}
+
+		n.Size = req.Size
+		return updateNode(tx, n)
+	})
+
+	if err != nil {
+		// Reset our size.
+		log.Print(err)
+		n.Size = originalSize
+		return err
+	}
+	return nil
+}
+
+// Lookup looks up a specific entry in the receiver,
+// which must be a directory.  Lookup should return a Node
+// corresponding to the entry.  If the name does not exist in
+// the directory, Lookup should return ENOENT.
+//
+// Lookup need not to handle the names "." and "..".
+func (n *Node) Lookup(_ context.Context, name string) (fs.Node, error) {
+	if !n.isDir() {
+		return nil, fuse.Errno(syscall.ENOTDIR)
+	}
+	node, err := n.cfs.lookup(n.ID, name)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return nil, fuse.ENOENT
+		}
+		return nil, err
+	}
+	node.cfs = n.cfs
+	return node, nil
+}
+
+// ReadDirAll returns the list of child inodes.
+func (n *Node) ReadDirAll(_ context.Context) ([]fuse.Dirent, error) {
+	if !n.isDir() {
+		return nil, fuse.Errno(syscall.ENOTDIR)
+	}
+	return n.cfs.list(n.ID)
+}
+
+// Mkdir creates a directory in 'n'.
+// We let the sql query fail if the directory already exists.
+// TODO(marc): better handling of errors.
+func (n *Node) Mkdir(ctx context.Context, req *fuse.MkdirRequest) (fs.Node, error) {
+	if !n.isDir() {
+		return nil, fuse.Errno(syscall.ENOTDIR)
+	}
+	if !req.Mode.IsDir() {
+		return nil, fuse.Errno(syscall.ENOTDIR)
+	}
+
+	node := n.cfs.newDirNode()
+	err := n.cfs.create(ctx, n.ID, req.Name, node)
+	if err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+// Create creates a new file in the receiver directory.
+func (n *Node) Create(
+	ctx context.Context, req *fuse.CreateRequest, resp *fuse.CreateResponse,
+) (fs.Node, fs.Handle, error) {
+	if !n.isDir() {
+		return nil, nil, fuse.Errno(syscall.ENOTDIR)
+	}
+	if req.Mode.IsDir() {
+		return nil, nil, fuse.Errno(syscall.EISDIR)
+	} else if !req.Mode.IsRegular() {
+		return nil, nil, fuse.Errno(syscall.EINVAL)
+	}
+
+	node := n.cfs.newFileNode()
+	err := n.cfs.create(ctx, n.ID, req.Name, node)
+	if err != nil {
+		return nil, nil, err
+	}
+	return node, node, nil
+}
+
+// Remove may be unlink or rmdir.
+func (n *Node) Remove(ctx context.Context, req *fuse.RemoveRequest) error {
+	if !n.isDir() {
+		return fuse.Errno(syscall.ENOTDIR)
+	}
+
+	if req.Dir {
+		// Rmdir.
+		return n.cfs.remove(ctx, n.ID, req.Name, true /* checkChildren */)
+	}
+	// Unlink file/symlink.
+	return n.cfs.remove(ctx, n.ID, req.Name, false /* !checkChildren */)
+}
+
+// Write writes data to 'n'. It may overwrite existing data, or grow it.
+func (n *Node) Write(ctx context.Context, req *fuse.WriteRequest, resp *fuse.WriteResponse) error {
+	if !n.isRegular() {
+		return fuse.Errno(syscall.EINVAL)
+	}
+	if req.Offset < 0 {
+		return fuse.Errno(syscall.EINVAL)
+	}
+	if len(req.Data) == 0 {
+		return nil
+	}
+
+	n.mu.Lock()
+	defer n.mu.Unlock()
+
+	newSize := uint64(req.Offset) + uint64(len(req.Data))
+	if newSize > maxSize {
+		return fuse.Errno(syscall.EFBIG)
+	}
+
+	// Store the current size in case we need to rollback.
+	originalSize := n.Size
+
+	// Wrap everything inside a transaction.
+	err := client.ExecuteTx(ctx, n.cfs.db, nil /* txopts */, func(tx *sql.Tx) error {
+
+		// Update blocks. They will be added as needed.
+		if err := write(tx, n.ID, n.Size, uint64(req.Offset), req.Data); err != nil {
+			return err
+		}
+
+		if newSize > originalSize {
+			// This was an append, commit the size change.
+			n.Size = newSize
+			if err := updateNode(tx, n); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+
+	if err != nil {
+		// Reset our size.
+		log.Print(err)
+		n.Size = originalSize
+		return err
+	}
+
+	// We always write everything.
+	resp.Size = len(req.Data)
+	return nil
+}
+
+// Read reads data from 'n'.
+func (n *Node) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
+	if !n.isRegular() {
+		return fuse.Errno(syscall.EINVAL)
+	}
+	if req.Offset < 0 {
+		// Before beginning of file.
+		return fuse.Errno(syscall.EINVAL)
+	}
+	if req.Size == 0 {
+		// No bytes requested.
+		return nil
+	}
+	offset := uint64(req.Offset)
+
+	n.mu.RLock()
+	defer n.mu.RUnlock()
+	if offset >= n.Size {
+		// Beyond end of file.
+		return nil
+	}
+
+	to := min(n.Size, offset+uint64(req.Size))
+	if offset == to {
+		return nil
+	}
+
+	data, err := read(n.cfs.db, n.ID, offset, to)
+	if err != nil {
+		return err
+	}
+	resp.Data = data
+	return nil
+}
+
+// Fsync is a noop for us, we always push writes to the DB. We do need to implement it though.
+func (n *Node) Fsync(_ context.Context, _ *fuse.FsyncRequest) error {
+	return nil
+}
+
+// Rename renames 'req.OldName' to 'req.NewName', optionally moving it to 'newDir'.
+// If req.NewName exists, it is deleted. It is assumed that it cannot be a directory.
+// NOTE: we do not keep track of opens, so we delete existing destinations right away.
+// This means that anyone holding an open file descriptor on the destination will fail
+// when trying to use it.
+// To properly handle this, we need to count references (including inode -> inode refs,
+// and open handles) and delete the inode only when it reaches zero.
+func (n *Node) Rename(ctx context.Context, req *fuse.RenameRequest, newDir fs.Node) error {
+	newNode, ok := newDir.(*Node)
+	if !ok {
+		return fmt.Errorf("newDir is not a Node: %v", newDir)
+	}
+	if !n.isDir() || !newNode.isDir() {
+		return fuse.Errno(syscall.ENOTDIR)
+	}
+	return n.cfs.rename(ctx, n.ID, newNode.ID, req.OldName, req.NewName)
+}
+
+// Symlink creates a new symbolic link in the receiver node, which must
+// be a directory.
+func (n *Node) Symlink(ctx context.Context, req *fuse.SymlinkRequest) (fs.Node, error) {
+	if !n.isDir() {
+		return nil, fuse.Errno(syscall.ENOTDIR)
+	}
+	if len(req.Target) > maxSymlinkTargetLength {
+		return nil, fuse.Errno(syscall.ENAMETOOLONG)
+	}
+	node := n.cfs.newSymlinkNode()
+	node.SymlinkTarget = req.Target
+	err := n.cfs.create(ctx, n.ID, req.NewName, node)
+	if err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+// Readlink reads a symbolic link.
+func (n *Node) Readlink(_ context.Context, req *fuse.ReadlinkRequest) (string, error) {
+	if !n.isSymlink() {
+		return "", fuse.Errno(syscall.EINVAL)
+	}
+	return n.SymlinkTarget, nil
+}
diff --git a/cmd/cql-fuse/randbytes.go b/cmd/cql-fuse/randbytes.go
new file mode 100644
index 000000000..e2532e875
--- /dev/null
+++ b/cmd/cql-fuse/randbytes.go
@@ -0,0 +1,62 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Copyright 2015 The Cockroach Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License. See the AUTHORS file
+// for names of contributors.
+//
+// Author: Marc Berhault (marc@cockroachlabs.com)
+package main
+
+import (
+	"math/rand"
+	"time"
+)
+
+var randLetters = []byte("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+
+// NewPseudoRand returns an instance of math/rand.Rand seeded from crypto/rand
+// and its seed so we can easily and cheaply generate unique streams of
+// numbers. The created object is not safe for concurrent access.
+func NewPseudoRand() (*rand.Rand, int64) {
+	seed := time.Now().UnixNano()
+	return rand.New(rand.NewSource(seed)), seed
+}
+
+// RandBytes returns a byte slice of the given length with random
+// data.
+func RandBytes(r *rand.Rand, size int) []byte {
+	if size <= 0 {
+		return nil
+	}
+
+	arr := make([]byte, size)
+	for i := 0; i < len(arr); i++ {
+		arr[i] = randLetters[r.Intn(len(randLetters))]
+	}
+	return arr
+}
diff --git a/cmd/cql-fuse/sql.go b/cmd/cql-fuse/sql.go
new file mode 100644
index 000000000..6009e78fd
--- /dev/null
+++ b/cmd/cql-fuse/sql.go
@@ -0,0 +1,153 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Copyright 2015 The Cockroach Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License. See the AUTHORS file
+// for names of contributors.
+//
+// Author: Marc Berhault (marc@cockroachlabs.com)
+
+package main
+
+import (
+	"database/sql"
+	"encoding/json"
+	"syscall"
+
+	"bazil.org/fuse"
+)
+
+// sqlExecutor is an interface needed for basic queries.
+// It is implemented by both sql.DB and sql.Txn.
+type sqlExecutor interface {
+	Exec(query string, args ...interface{}) (sql.Result, error)
+	Query(query string, args ...interface{}) (*sql.Rows, error)
+	QueryRow(query string, args ...interface{}) *sql.Row
+}
+
+// getInode looks up an inode given its name and its parent ID.
+// If not found, error will be sql.ErrNoRows.
+func getInode(e sqlExecutor, parentID uint64, name string) (*Node, error) {
+	var raw string
+	const sql = `SELECT inode FROM fs_inode WHERE id = 
+(SELECT id FROM fs_namespace WHERE (parentID, name) = (?, ?))`
+	if err := e.QueryRow(sql, parentID, name).Scan(&raw); err != nil {
+		return nil, err
+	}
+
+	node := &Node{}
+	err := json.Unmarshal([]byte(raw), node)
+	return node, err
+}
+
+// checkIsEmpty returns nil if 'id' has no children.
+func checkIsEmpty(e sqlExecutor, id uint64) error {
+	var count uint64
+	const countSQL = `
+SELECT COUNT(parentID) FROM fs_namespace WHERE parentID = ?`
+	if err := e.QueryRow(countSQL, id).Scan(&count); err != nil {
+		return err
+	}
+	if count != 0 {
+		return fuse.Errno(syscall.ENOTEMPTY)
+	}
+	return nil
+}
+
+// updateNode updates an existing node descriptor.
+func updateNode(e sqlExecutor, node *Node) error {
+	inode := node.toJSON()
+	const sql = `
+UPDATE fs_inode SET inode = ? WHERE id = ?;
+`
+	if _, err := e.Exec(sql, inode, node.ID); err != nil {
+		return err
+	}
+	return nil
+}
+
+// getBlockData returns the block data for a single block.
+func getBlockData(e sqlExecutor, inodeID uint64, block int) ([]byte, error) {
+	var data []byte
+	const sql = `SELECT data FROM fs_block WHERE id = ? AND block = ?`
+	if err := e.QueryRow(sql, inodeID, block).Scan(&data); err != nil {
+		return nil, err
+	}
+	return data, nil
+}
+
+// updateBlockData overwrites the data for a single block.
+func updateBlockData(e sqlExecutor, inodeID uint64, block int, data []byte) error {
+	const sql = `UPDATE fs_block SET data = ? WHERE (id, block) = (?, ?)`
+	if _, err := e.Exec(sql, data, inodeID, block); err != nil {
+		return err
+	}
+	return nil
+}
+
+type blockInfo struct {
+	block int
+	data  []byte
+}
+
+// getBlocks fetches all the blocks for a given inode and returns
+// a list of blockInfo objects.
+func getBlocks(e sqlExecutor, inodeID uint64) ([]blockInfo, error) {
+	stmt := `SELECT block, data FROM fs_block WHERE id = ?`
+	rows, err := e.Query(stmt, inodeID)
+	if err != nil {
+		return nil, err
+	}
+	return buildBlockInfos(rows)
+}
+
+// getBlocksBetween fetches blocks with IDs [start, end] for a given inode
+// and returns a list of blockInfo objects.
+func getBlocksBetween(e sqlExecutor, inodeID uint64, start, end int) ([]blockInfo, error) {
+	stmt := `SELECT block, data FROM fs_block WHERE id = ? AND block >= ? AND block <= ?`
+	rows, err := e.Query(stmt, inodeID, start, end)
+	if err != nil {
+		return nil, err
+	}
+	return buildBlockInfos(rows)
+}
+
+func buildBlockInfos(rows *sql.Rows) ([]blockInfo, error) {
+	var results []blockInfo
+	for rows.Next() {
+		b := blockInfo{}
+		if err := rows.Scan(&b.block, &b.data); err != nil {
+			return nil, err
+		}
+		results = append(results, b)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+
+	return results, nil
+}
diff --git a/cmd/cql-minerd/benchGNTE.sh b/cmd/cql-minerd/benchGNTE.sh
index b26b2d207..fd6da72bb 100755
--- a/cmd/cql-minerd/benchGNTE.sh
+++ b/cmd/cql-minerd/benchGNTE.sh
@@ -6,3 +6,21 @@ go test -bench=^BenchmarkMinerGNTE2$ -benchtime=10s -run ^$ && \
 go test -bench=^BenchmarkMinerGNTE3$ -benchtime=10s -run ^$ && \
 go test -bench=^BenchmarkMinerGNTE4$ -benchtime=10s -run ^$ && \
 go test -bench=^BenchmarkMinerGNTE8$ -benchtime=10s -run ^$
+
+go test -cpu=4 -bench=^BenchmarkMinerGNTE1$ -benchtime=10s -run ^$ && \
+go test -cpu=4 -bench=^BenchmarkMinerGNTE2$ -benchtime=10s -run ^$ && \
+go test -cpu=4 -bench=^BenchmarkMinerGNTE3$ -benchtime=10s -run ^$ && \
+go test -cpu=4 -bench=^BenchmarkMinerGNTE4$ -benchtime=10s -run ^$ && \
+go test -cpu=4 -bench=^BenchmarkMinerGNTE8$ -benchtime=10s -run ^$
+
+go test -cpu=2 -bench=^BenchmarkMinerGNTE1$ -benchtime=10s -run ^$ && \
+go test -cpu=2 -bench=^BenchmarkMinerGNTE2$ -benchtime=10s -run ^$ && \
+go test -cpu=2 -bench=^BenchmarkMinerGNTE3$ -benchtime=10s -run ^$ && \
+go test -cpu=2 -bench=^BenchmarkMinerGNTE4$ -benchtime=10s -run ^$ && \
+go test -cpu=2 -bench=^BenchmarkMinerGNTE8$ -benchtime=10s -run ^$
+
+go test -cpu=1 -bench=^BenchmarkMinerGNTE1$ -benchtime=10s -run ^$ && \
+go test -cpu=1 -bench=^BenchmarkMinerGNTE2$ -benchtime=10s -run ^$ && \
+go test -cpu=1 -bench=^BenchmarkMinerGNTE3$ -benchtime=10s -run ^$ && \
+go test -cpu=1 -bench=^BenchmarkMinerGNTE4$ -benchtime=10s -run ^$ && \
+go test -cpu=1 -bench=^BenchmarkMinerGNTE8$ -benchtime=10s -run ^$
diff --git a/cmd/cql-minerd/dbms.go b/cmd/cql-minerd/dbms.go
index d117aec44..d033f16de 100644
--- a/cmd/cql-minerd/dbms.go
+++ b/cmd/cql-minerd/dbms.go
@@ -30,10 +30,9 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/pow/cpuminer"
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/worker"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 	"github.com/pkg/errors"
 )
 
@@ -88,14 +87,14 @@ func startDBMS(server *rpc.Server) (dbms *worker.DBMS, err error) {
 			}
 
 			// load genesis block
-			var block *ct.Block
+			var block *types.Block
 			if block, err = loadGenesisBlock(testFixture); err != nil {
 				err = errors.Wrap(err, "load genesis block failed")
 				return
 			}
 
 			// add to dbms
-			instance := &wt.ServiceInstance{
+			instance := &types.ServiceInstance{
 				DatabaseID:   testFixture.DatabaseID,
 				Peers:        dbPeers,
 				GenesisBlock: block,
@@ -110,7 +109,7 @@ func startDBMS(server *rpc.Server) (dbms *worker.DBMS, err error) {
 	return
 }
 
-func loadGenesisBlock(fixture *conf.MinerDatabaseFixture) (block *ct.Block, err error) {
+func loadGenesisBlock(fixture *conf.MinerDatabaseFixture) (block *types.Block, err error) {
 	if fixture.GenesisBlockFile == "" {
 		err = os.ErrNotExist
 		return
@@ -148,7 +147,7 @@ func loadGenesisBlock(fixture *conf.MinerDatabaseFixture) (block *ct.Block, err
 }
 
 // copied from sqlchain.xxx_test.
-func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error) {
+func createRandomBlock(parent hash.Hash, isGenesis bool) (b *types.Block, err error) {
 	// Generate key pair
 	priv, pub, err := asymmetric.GenSecp256k1KeyPair()
 
@@ -159,9 +158,9 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 	h := hash.Hash{}
 	rand.Read(h[:])
 
-	b = &ct.Block{
-		SignedHeader: ct.SignedHeader{
-			Header: ct.Header{
+	b = &types.Block{
+		SignedHeader: types.SignedHeader{
+			Header: types.Header{
 				Version:     0x01000000,
 				Producer:    proto.NodeID(h.String()),
 				GenesisHash: rootHash,
@@ -169,12 +168,6 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 				Timestamp:   time.Now().UTC(),
 			},
 		},
-		Queries: make([]*hash.Hash, rand.Intn(10)+10),
-	}
-
-	for i := range b.Queries {
-		b.Queries[i] = new(hash.Hash)
-		rand.Read(b.Queries[i][:])
 	}
 
 	if isGenesis {
diff --git a/cmd/cql-minerd/integration_test.go b/cmd/cql-minerd/integration_test.go
index eedc70c67..bd6237d67 100644
--- a/cmd/cql-minerd/integration_test.go
+++ b/cmd/cql-minerd/integration_test.go
@@ -21,11 +21,13 @@ package main
 import (
 	"context"
 	"database/sql"
+	"fmt"
 	"io/ioutil"
 	"math/rand"
 	"os"
 	"os/exec"
 	"path/filepath"
+	"runtime"
 	"sync"
 	"sync/atomic"
 	"syscall"
@@ -36,6 +38,7 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
+	"github.com/CovenantSQL/go-sqlite3-encrypt"
 	. "github.com/smartystreets/goconvey/convey"
 )
 
@@ -326,7 +329,7 @@ func TestFullProcess(t *testing.T) {
 		So(err, ShouldBeNil)
 
 		// create
-		dsn, err := client.Create(client.ResourceMeta{Node: 1})
+		dsn, err := client.Create(client.ResourceMeta{Node: 2})
 		So(err, ShouldBeNil)
 
 		log.Infof("the created database dsn is %v", dsn)
@@ -389,17 +392,22 @@ func TestFullProcess(t *testing.T) {
 	})
 }
 
+const ROWSTART = 1000000
+const TABLENAME = "insert_table0"
+
 func prepareBenchTable(db *sql.DB) {
-	_, err := db.Exec("DROP TABLE IF EXISTS test;")
+	_, err := db.Exec("DROP TABLE IF EXISTS " + TABLENAME + ";")
 	So(err, ShouldBeNil)
 
-	_, err = db.Exec("CREATE TABLE test ( indexedColumn, nonIndexedColumn );")
+	_, err = db.Exec(`CREATE TABLE ` + TABLENAME + ` ("k" INT, "v1" TEXT, PRIMARY KEY("k"))`)
 	So(err, ShouldBeNil)
 
-	_, err = db.Exec("CREATE INDEX testIndexedColumn ON test ( indexedColumn );")
+	_, err = db.Exec("REPLACE INTO "+TABLENAME+" VALUES(?, ?)", ROWSTART-1, "test")
 	So(err, ShouldBeNil)
+}
 
-	_, err = db.Exec("INSERT INTO test VALUES(?, ?)", 4, 4)
+func cleanBenchTable(db *sql.DB) {
+	_, err := db.Exec("DELETE FROM "+TABLENAME+" WHERE k >= ?", ROWSTART)
 	So(err, ShouldBeNil)
 }
 
@@ -409,38 +417,26 @@ func benchDB(b *testing.B, db *sql.DB, createDB bool) {
 		prepareBenchTable(db)
 	}
 
-	var i int32
-	var insertedCount int
-
-	rand.Seed(time.Now().UnixNano())
-	start := (rand.Int31() % 100) * 10000
-
-	//b.Run("benchmark Single INSERT", func(b *testing.B) {
-	//	b.ResetTimer()
-	//	insertedCount = b.N
-	//	for i := 0; i < b.N; i++ {
-	//		_, err = db.Exec("INSERT INTO test ( indexedColumn, nonIndexedColumn ) VALUES"+
-	//			"(?, ?)", int(start)+i, i,
-	//		)
-	//		if err != nil {
-	//			b.Fatal(err)
-	//		}
-	//	}
-	//})
-	//
-	//if createDB {
-	//	prepareBenchTable(db)
-	//}
-	//
-	b.Run("benchmark Multi INSERT", func(b *testing.B) {
+	cleanBenchTable(db)
+
+	var i int64
+	i = -1
+
+	b.Run("benchmark INSERT", func(b *testing.B) {
 		b.ResetTimer()
-		insertedCount = b.N
 		b.RunParallel(func(pb *testing.PB) {
 			for pb.Next() {
-				ii := atomic.AddInt32(&i, 1)
-				_, err = db.Exec("INSERT INTO test ( indexedColumn, nonIndexedColumn ) VALUES"+
-					"(?, ?)", start+ii, ii,
+				ii := atomic.AddInt64(&i, 1)
+				_, err = db.Exec("INSERT INTO "+TABLENAME+" ( k, v1 ) VALUES"+
+					"(?, ?)", ROWSTART+ii, ii,
 				)
+				for err != nil && err.Error() == sqlite3.ErrBusy.Error() {
+					// retry forever
+					log.Warnf("ROWSTART+ii = %d retried", ROWSTART+ii)
+					_, err = db.Exec("INSERT INTO "+TABLENAME+" ( k, v1 ) VALUES"+
+						"(?, ?)", ROWSTART+ii, ii,
+					)
+				}
 				if err != nil {
 					b.Fatal(err)
 				}
@@ -448,37 +444,56 @@ func benchDB(b *testing.B, db *sql.DB, createDB bool) {
 		})
 	})
 
-	rowCount := db.QueryRow("SELECT COUNT(1) FROM test")
-	var count int
+	routineCount := runtime.NumGoroutine()
+	if routineCount > 100 {
+		b.Errorf("go routine count: %d", routineCount)
+	} else {
+		log.Infof("go routine count: %d", routineCount)
+	}
+
+	rowCount := db.QueryRow("SELECT COUNT(1) FROM " + TABLENAME)
+	var count int64
 	err = rowCount.Scan(&count)
 	if err != nil {
 		b.Fatal(err)
 	}
-	log.Warnf("Row Count: %d", count)
+	log.Warnf("Row Count: %v", count)
 
 	b.Run("benchmark SELECT", func(b *testing.B) {
 		b.ResetTimer()
 		b.RunParallel(func(pb *testing.PB) {
 			for pb.Next() {
-				i := atomic.AddInt32(&i, 1)
-				index := int(i)%insertedCount + int(start) + 1
-				row := db.QueryRow("SELECT nonIndexedColumn FROM test WHERE indexedColumn = ? LIMIT 1", index)
-				var result int
+				var index int64
+				if createDB { //only data by insert
+					index = rand.Int63n(count-1) + ROWSTART
+				} else { //has data before ROWSTART
+					index = rand.Int63n(count - 1)
+				}
+				//log.Debugf("index = %d", index)
+				row := db.QueryRow("SELECT v1 FROM "+TABLENAME+" WHERE k = ? LIMIT 1", index)
+				var result []byte
 				err = row.Scan(&result)
-				if err != nil || result < 0 {
-					log.Errorf("i = %d", i)
+				if err != nil || (len(result) == 0) {
+					log.Errorf("index = %d", index)
 					b.Fatal(err)
 				}
 			}
 		})
 	})
 
-	row := db.QueryRow("SELECT nonIndexedColumn FROM test LIMIT 1")
+	routineCount = runtime.NumGoroutine()
+	if routineCount > 100 {
+		b.Errorf("go routine count: %d", routineCount)
+	} else {
+		log.Infof("go routine count: %d", routineCount)
+	}
 
-	var result int
-	err = row.Scan(&result)
-	So(err, ShouldBeNil)
-	So(result, ShouldEqual, 4)
+	//row := db.QueryRow("SELECT nonIndexedColumn FROM test LIMIT 1")
+
+	//var result int
+	//err = row.Scan(&result)
+	//So(err, ShouldBeNil)
+	//So(result, ShouldEqual, 4)
 
 	err = db.Close()
 	So(err, ShouldBeNil)
@@ -487,18 +502,18 @@ func benchDB(b *testing.B, db *sql.DB, createDB bool) {
 func benchMiner(b *testing.B, minerCount uint16, bypassSign bool) {
 	log.Warnf("Benchmark for %d Miners, BypassSignature: %v", minerCount, bypassSign)
 	asymmetric.BypassSignature = bypassSign
-	//if minerCount > 0 {
-	//	startNodesProfile(bypassSign)
-	//	utils.WaitToConnect(context.Background(), "127.0.0.1", []int{
-	//		2144,
-	//		2145,
-	//		2146,
-	//		3122,
-	//		3121,
-	//		3120,
-	//	}, 2*time.Second)
-	//	time.Sleep(time.Second)
-	//}
+	if minerCount > 0 {
+		startNodesProfile(bypassSign)
+		utils.WaitToConnect(context.Background(), "127.0.0.1", []int{
+			2144,
+			2145,
+			2146,
+			3122,
+			3121,
+			3120,
+		}, 2*time.Second)
+		time.Sleep(time.Second)
+	}
 
 	// Create temp directory
 	testDataDir, err := ioutil.TempDir(testWorkingDir, "covenantsql")
@@ -506,9 +521,9 @@ func benchMiner(b *testing.B, minerCount uint16, bypassSign bool) {
 		panic(err)
 	}
 	defer os.RemoveAll(testDataDir)
-	clientConf := FJ(testWorkingDir, "./service/node_c/config.yaml")
+	clientConf := FJ(testWorkingDir, "./integration/node_c/config.yaml")
 	tempConf := FJ(testDataDir, "config.yaml")
-	clientKey := FJ(testWorkingDir, "./service/node_c/private.key")
+	clientKey := FJ(testWorkingDir, "./integration/node_c/private.key")
 	tempKey := FJ(testDataDir, "private.key")
 	utils.CopyFile(clientConf, tempConf)
 	utils.CopyFile(clientKey, tempKey)
@@ -536,7 +551,7 @@ func benchMiner(b *testing.B, minerCount uint16, bypassSign bool) {
 	db, err := sql.Open("covenantsql", dsn)
 	So(err, ShouldBeNil)
 
-	benchDB(b, db, true)
+	benchDB(b, db, minerCount > 0)
 
 	err = client.Drop(dsn)
 	So(err, ShouldBeNil)
@@ -545,17 +560,33 @@ func benchMiner(b *testing.B, minerCount uint16, bypassSign bool) {
 }
 
 func BenchmarkSQLite(b *testing.B) {
-	os.Remove("./foo.db")
-	defer os.Remove("./foo.db")
-
-	db, err := sql.Open("sqlite3", "./foo.db?_journal_mode=WAL&_synchronous=NORMAL&cache=shared")
-	if err != nil {
-		log.Fatal(err)
+	var db *sql.DB
+	var createDB bool
+	millionFile := fmt.Sprintf("/data/sqlite_bigdata/insert_multi_sqlitedb0_1_%v", ROWSTART)
+	f, err := os.Open(millionFile)
+	if err != nil && os.IsNotExist(err) {
+		os.Remove("./foo.db")
+		defer os.Remove("./foo.db")
+
+		db, err = sql.Open("sqlite3", "./foo.db?_journal_mode=WAL&_synchronous=NORMAL&cache=shared")
+		if err != nil {
+			log.Fatal(err)
+		}
+		createDB = true
+		defer db.Close()
+	} else {
+		f.Close()
+		db, err = sql.Open("sqlite3", millionFile+"?_journal_mode=WAL&_synchronous=NORMAL&cache=shared")
+		log.Infof("Testing sqlite3 million data exist file %v", millionFile)
+		if err != nil {
+			log.Fatal(err)
+		}
+		createDB = false
+		defer db.Close()
 	}
-	defer db.Close()
 
 	Convey("bench SQLite", b, func() {
-		benchDB(b, db, true)
+		benchDB(b, db, createDB)
 	})
 }
 
diff --git a/cmd/cql-minerd/main.go b/cmd/cql-minerd/main.go
index 716bd8fee..1dfbd5b34 100644
--- a/cmd/cql-minerd/main.go
+++ b/cmd/cql-minerd/main.go
@@ -26,7 +26,7 @@ import (
 	"os"
 	"os/signal"
 	"runtime"
-	"runtime/trace"
+	//"runtime/trace"
 	"syscall"
 	"time"
 
@@ -254,22 +254,22 @@ func main() {
 		go graphite.Graphite(metrics.DefaultRegistry, 5*time.Second, minerName, addr)
 	}
 
-	if traceFile != "" {
-		f, err := os.Create(traceFile)
-		if err != nil {
-			log.WithError(err).Fatal("failed to create trace output file")
-		}
-		defer func() {
-			if err := f.Close(); err != nil {
-				log.WithError(err).Fatal("failed to close trace file")
-			}
-		}()
-
-		if err := trace.Start(f); err != nil {
-			log.WithError(err).Fatal("failed to start trace")
-		}
-		defer trace.Stop()
-	}
+	//if traceFile != "" {
+	//	f, err := os.Create(traceFile)
+	//	if err != nil {
+	//		log.WithError(err).Fatal("failed to create trace output file")
+	//	}
+	//	defer func() {
+	//		if err := f.Close(); err != nil {
+	//			log.WithError(err).Fatal("failed to close trace file")
+	//		}
+	//	}()
+
+	//	if err := trace.Start(f); err != nil {
+	//		log.WithError(err).Fatal("failed to start trace")
+	//	}
+	//	defer trace.Stop()
+	//}
 
 	<-signalCh
 
diff --git a/cmd/cql-mysql-adapter/cursor.go b/cmd/cql-mysql-adapter/cursor.go
index 1622f5537..7583c1996 100644
--- a/cmd/cql-mysql-adapter/cursor.go
+++ b/cmd/cql-mysql-adapter/cursor.go
@@ -290,7 +290,7 @@ func (c *Cursor) UseDB(dbName string) (err error) {
 }
 
 // HandleQuery handle COM_QUERY comamnd, like SELECT, INSERT, UPDATE, etc...
-// if Result has a Resultset (SELECT, SHOW, etc...), we will send this as the repsonse, otherwise, we will send Result.
+// if Result has a Resultset (SELECT, SHOW, etc...), we will send this as the response, otherwise, we will send Result.
 func (c *Cursor) HandleQuery(query string) (r *my.Result, err error) {
 	var processed bool
 
diff --git a/cmd/cql-observer/api.go b/cmd/cql-observer/api.go
index 61b82aee0..8e4c0c483 100644
--- a/cmd/cql-observer/api.go
+++ b/cmd/cql-observer/api.go
@@ -27,9 +27,8 @@ import (
 
 	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
 	"github.com/CovenantSQL/CovenantSQL/proto"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 	"github.com/gorilla/mux"
 )
 
@@ -50,6 +49,10 @@ func sendResponse(code int, success bool, msg interface{}, data interface{}, rw
 	})
 }
 
+func notSupported(rw http.ResponseWriter, _ *http.Request) {
+	sendResponse(500, false, fmt.Sprintf("not supported in %v", version), nil, rw)
+}
+
 type explorerAPI struct {
 	service *Service
 }
@@ -76,26 +79,7 @@ func (a *explorerAPI) GetAck(rw http.ResponseWriter, r *http.Request) {
 	}
 
 	// format ack to json response
-	sendResponse(200, true, "", map[string]interface{}{
-		"ack": map[string]interface{}{
-			"request": map[string]interface{}{
-				"hash":      ack.Response.Request.Hash.String(),
-				"timestamp": a.formatTime(ack.Response.Request.Timestamp),
-				"node":      ack.Response.Request.NodeID,
-				"type":      ack.Response.Request.QueryType.String(),
-				"count":     ack.Response.Request.BatchCount,
-			},
-			"response": map[string]interface{}{
-				"hash":         ack.Response.Hash.String(),
-				"timestamp":    a.formatTime(ack.Response.Timestamp),
-				"node":         ack.Response.NodeID,
-				"log_position": ack.Response.LogOffset,
-			},
-			"hash":      ack.Hash.String(),
-			"timestamp": a.formatTime(ack.AckHeader.Timestamp),
-			"node":      ack.AckHeader.NodeID,
-		},
-	}, rw)
+	sendResponse(200, true, "", a.formatAck(ack), rw)
 }
 
 func (a *explorerAPI) GetRequest(rw http.ResponseWriter, r *http.Request) {
@@ -122,7 +106,7 @@ func (a *explorerAPI) GetRequest(rw http.ResponseWriter, r *http.Request) {
 	sendResponse(200, true, "", a.formatRequest(req), rw)
 }
 
-func (a *explorerAPI) GetRequestByOffset(rw http.ResponseWriter, r *http.Request) {
+func (a *explorerAPI) GetResponse(rw http.ResponseWriter, r *http.Request) {
 	vars := mux.Vars(r)
 
 	dbID, err := a.getDBID(vars)
@@ -131,28 +115,46 @@ func (a *explorerAPI) GetRequestByOffset(rw http.ResponseWriter, r *http.Request
 		return
 	}
 
-	offsetStr := vars["offset"]
-	if offsetStr == "" {
-		sendResponse(400, false, "", nil, rw)
+	h, err := a.getHash(vars)
+	if err != nil {
+		sendResponse(400, false, err, nil, rw)
 		return
 	}
 
-	offset, err := strconv.ParseUint(offsetStr, 10, 64)
+	resp, err := a.service.getResponseHeader(dbID, h)
+	if err != nil {
+		sendResponse(500, false, err, nil, rw)
+		return
+	}
+
+	sendResponse(200, true, "", a.formatResponseHeader(resp), rw)
+}
+
+func (a *explorerAPI) GetBlock(rw http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+
+	dbID, err := a.getDBID(vars)
+	if err != nil {
+		sendResponse(400, false, err, nil, rw)
+		return
+	}
+
+	h, err := a.getHash(vars)
 	if err != nil {
 		sendResponse(400, false, err, nil, rw)
 		return
 	}
 
-	req, err := a.service.getRequestByOffset(dbID, offset)
+	_, height, block, err := a.service.getBlock(dbID, h)
 	if err != nil {
 		sendResponse(500, false, err, nil, rw)
 		return
 	}
 
-	sendResponse(200, true, "", a.formatRequest(req), rw)
+	sendResponse(200, true, "", a.formatBlock(height, block), rw)
 }
 
-func (a *explorerAPI) GetBlock(rw http.ResponseWriter, r *http.Request) {
+func (a *explorerAPI) GetBlockV3(rw http.ResponseWriter, r *http.Request) {
 	vars := mux.Vars(r)
 
 	dbID, err := a.getDBID(vars)
@@ -167,13 +169,13 @@ func (a *explorerAPI) GetBlock(rw http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	height, block, err := a.service.getBlock(dbID, h)
+	count, height, block, err := a.service.getBlock(dbID, h)
 	if err != nil {
 		sendResponse(500, false, err, nil, rw)
 		return
 	}
 
-	sendResponse(200, true, "", a.formatBlock(height, block), rw)
+	sendResponse(200, true, "", a.formatBlockV3(count, height, block), rw)
 }
 
 func (a *explorerAPI) GetBlockByCount(rw http.ResponseWriter, r *http.Request) {
@@ -187,7 +189,7 @@ func (a *explorerAPI) GetBlockByCount(rw http.ResponseWriter, r *http.Request) {
 
 	countStr := vars["count"]
 	if countStr == "" {
-		sendResponse(400, false, "", nil, rw)
+		sendResponse(400, false, "empty count", nil, rw)
 		return
 	}
 
@@ -208,6 +210,38 @@ func (a *explorerAPI) GetBlockByCount(rw http.ResponseWriter, r *http.Request) {
 	sendResponse(200, true, "", a.formatBlockV2(count, height, block), rw)
 }
 
+func (a *explorerAPI) GetBlockByCountV3(rw http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+
+	dbID, err := a.getDBID(vars)
+	if err != nil {
+		sendResponse(400, false, err, nil, rw)
+		return
+	}
+
+	countStr := vars["count"]
+	if countStr == "" {
+		sendResponse(400, false, "empty count", nil, rw)
+		return
+	}
+
+	countNumber, err := strconv.ParseInt(countStr, 10, 32)
+	if err != nil {
+		sendResponse(400, false, err, nil, rw)
+		return
+	}
+
+	count := int32(countNumber)
+
+	height, block, err := a.service.getBlockByCount(dbID, count)
+	if err != nil {
+		sendResponse(500, false, err, nil, rw)
+		return
+	}
+
+	sendResponse(200, true, "", a.formatBlockV3(count, height, block), rw)
+}
+
 func (a *explorerAPI) GetBlockByHeight(rw http.ResponseWriter, r *http.Request) {
 	vars := mux.Vars(r)
 
@@ -219,7 +253,7 @@ func (a *explorerAPI) GetBlockByHeight(rw http.ResponseWriter, r *http.Request)
 
 	heightStr := vars["height"]
 	if heightStr == "" {
-		sendResponse(400, false, "", nil, rw)
+		sendResponse(400, false, "empty height", nil, rw)
 		return
 	}
 
@@ -231,7 +265,7 @@ func (a *explorerAPI) GetBlockByHeight(rw http.ResponseWriter, r *http.Request)
 
 	height := int32(heightNumber)
 
-	block, err := a.service.getBlockByHeight(dbID, height)
+	_, block, err := a.service.getBlockByHeight(dbID, height)
 	if err != nil {
 		sendResponse(500, false, err, nil, rw)
 		return
@@ -240,7 +274,39 @@ func (a *explorerAPI) GetBlockByHeight(rw http.ResponseWriter, r *http.Request)
 	sendResponse(200, true, "", a.formatBlock(height, block), rw)
 }
 
-func (a *explorerAPI) getHighestBlock(rw http.ResponseWriter, r *http.Request) {
+func (a *explorerAPI) GetBlockByHeightV3(rw http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+
+	dbID, err := a.getDBID(vars)
+	if err != nil {
+		sendResponse(400, false, err, nil, rw)
+		return
+	}
+
+	heightStr := vars["height"]
+	if heightStr == "" {
+		sendResponse(400, false, "empty height", nil, rw)
+		return
+	}
+
+	heightNumber, err := strconv.ParseInt(heightStr, 10, 32)
+	if err != nil {
+		sendResponse(400, false, err, nil, rw)
+		return
+	}
+
+	height := int32(heightNumber)
+
+	count, block, err := a.service.getBlockByHeight(dbID, height)
+	if err != nil {
+		sendResponse(500, false, err, nil, rw)
+		return
+	}
+
+	sendResponse(200, true, "", a.formatBlockV3(count, height, block), rw)
+}
+
+func (a *explorerAPI) GetHighestBlock(rw http.ResponseWriter, r *http.Request) {
 	vars := mux.Vars(r)
 
 	dbID, err := a.getDBID(vars)
@@ -271,7 +337,7 @@ func (a *explorerAPI) getHighestBlock(rw http.ResponseWriter, r *http.Request) {
 	sendResponse(200, true, "", a.formatBlock(height, block), rw)
 }
 
-func (a *explorerAPI) getHighestBlockV2(rw http.ResponseWriter, r *http.Request) {
+func (a *explorerAPI) GetHighestBlockV2(rw http.ResponseWriter, r *http.Request) {
 	vars := mux.Vars(r)
 
 	dbID, err := a.getDBID(vars)
@@ -302,36 +368,46 @@ func (a *explorerAPI) getHighestBlockV2(rw http.ResponseWriter, r *http.Request)
 	sendResponse(200, true, "", a.formatBlockV2(count, height, block), rw)
 }
 
-func (a *explorerAPI) formatBlock(height int32, b *ct.Block) map[string]interface{} {
-	queries := make([]string, 0, len(b.Queries))
+func (a *explorerAPI) GetHighestBlockV3(rw http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
 
-	for _, q := range b.Queries {
-		queries = append(queries, q.String())
+	dbID, err := a.getDBID(vars)
+	if err != nil {
+		sendResponse(400, false, err, nil, rw)
+		return
 	}
 
-	return map[string]interface{}{
-		"block": map[string]interface{}{
-			"height":       height,
-			"hash":         b.BlockHash().String(),
-			"genesis_hash": b.GenesisHash().String(),
-			"timestamp":    a.formatTime(b.Timestamp()),
-			"version":      b.SignedHeader.Version,
-			"producer":     b.Producer(),
-			"queries":      queries,
-		},
+	count, height, block, err := a.service.getHighestBlockV2(dbID)
+	if err == ErrNotFound {
+		// try to add subscription
+		err = a.service.subscribe(dbID, "oldest")
+		if err == nil {
+			count, height, block, err = a.service.getHighestBlockV2(dbID)
+			if err != nil {
+				sendResponse(500, false, err, nil, rw)
+				return
+			}
+		} else {
+			sendResponse(400, false, err, nil, rw)
+			return
+		}
+	} else if err != nil {
+		sendResponse(500, false, err, nil, rw)
+		return
 	}
+
+	sendResponse(200, true, "", a.formatBlockV3(count, height, block), rw)
 }
 
-func (a *explorerAPI) formatBlockV2(count, height int32, b *ct.Block) map[string]interface{} {
-	queries := make([]string, 0, len(b.Queries))
+func (a *explorerAPI) formatBlock(height int32, b *types.Block) (res map[string]interface{}) {
+	queries := make([]string, 0, len(b.Acks))
 
-	for _, q := range b.Queries {
-		queries = append(queries, q.String())
+	for _, q := range b.Acks {
+		queries = append(queries, q.Hash().String())
 	}
 
 	return map[string]interface{}{
 		"block": map[string]interface{}{
-			"count":        count,
 			"height":       height,
 			"hash":         b.BlockHash().String(),
 			"genesis_hash": b.GenesisHash().String(),
@@ -343,7 +419,40 @@ func (a *explorerAPI) formatBlockV2(count, height int32, b *ct.Block) map[string
 	}
 }
 
-func (a *explorerAPI) formatRequest(req *wt.Request) map[string]interface{} {
+func (a *explorerAPI) formatBlockV2(count, height int32, b *types.Block) (res map[string]interface{}) {
+	res = a.formatBlock(height, b)
+	res["block"].(map[string]interface{})["count"] = count
+	return
+}
+
+func (a *explorerAPI) formatBlockV3(count, height int32, b *types.Block) (res map[string]interface{}) {
+	res = a.formatBlockV2(count, height, b)
+	blockRes := res["block"].(map[string]interface{})
+	blockRes["acks"] = func() (acks []interface{}) {
+		acks = make([]interface{}, 0, len(b.Acks))
+
+		for _, ack := range b.Acks {
+			acks = append(acks, a.formatAck(ack)["ack"])
+		}
+
+		return
+	}()
+	blockRes["queries"] = func() (tracks []interface{}) {
+		tracks = make([]interface{}, 0, len(b.QueryTxs))
+
+		for _, tx := range b.QueryTxs {
+			t := a.formatRequest(tx.Request)
+			t["response"] = a.formatResponseHeader(tx.Response)["response"]
+			tracks = append(tracks, t)
+		}
+
+		return
+	}()
+
+	return
+}
+
+func (a *explorerAPI) formatRequest(req *types.Request) map[string]interface{} {
 	// get queries
 	queries := make([]map[string]interface{}, 0, req.Header.BatchCount)
 
@@ -365,7 +474,7 @@ func (a *explorerAPI) formatRequest(req *wt.Request) map[string]interface{} {
 
 	return map[string]interface{}{
 		"request": map[string]interface{}{
-			"hash":      req.Header.Hash.String(),
+			"hash":      req.Header.Hash().String(),
 			"timestamp": a.formatTime(req.Header.Timestamp),
 			"node":      req.Header.NodeID,
 			"type":      req.Header.QueryType.String(),
@@ -375,6 +484,52 @@ func (a *explorerAPI) formatRequest(req *wt.Request) map[string]interface{} {
 	}
 }
 
+func (a *explorerAPI) formatResponseHeader(resp *types.SignedResponseHeader) map[string]interface{} {
+	return map[string]interface{}{
+		"response": map[string]interface{}{
+			"hash":           resp.Hash().String(),
+			"timestamp":      a.formatTime(resp.Timestamp),
+			"node":           resp.NodeID,
+			"row_count":      resp.RowCount,
+			"log_id":         resp.LogOffset,
+			"last_insert_id": resp.LastInsertID,
+			"affected_rows":  resp.AffectedRows,
+		},
+		"request": map[string]interface{}{
+			"hash":      resp.Request.Hash().String(),
+			"timestamp": a.formatTime(resp.Request.Timestamp),
+			"node":      resp.Request.NodeID,
+			"type":      resp.Request.QueryType.String(),
+			"count":     resp.Request.BatchCount,
+		},
+	}
+}
+
+func (a *explorerAPI) formatAck(ack *types.SignedAckHeader) map[string]interface{} {
+	return map[string]interface{}{
+		"ack": map[string]interface{}{
+			"request": map[string]interface{}{
+				"hash":      ack.Response.Request.Hash().String(),
+				"timestamp": a.formatTime(ack.Response.Request.Timestamp),
+				"node":      ack.Response.Request.NodeID,
+				"type":      ack.Response.Request.QueryType.String(),
+				"count":     ack.Response.Request.BatchCount,
+			},
+			"response": map[string]interface{}{
+				"hash":           ack.Response.Hash().String(),
+				"timestamp":      a.formatTime(ack.Response.Timestamp),
+				"node":           ack.Response.NodeID,
+				"log_id":         ack.Response.LogOffset, // savepoint id in eventual consistency mode
+				"last_insert_id": ack.Response.LastInsertID,
+				"affected_rows":  ack.Response.AffectedRows,
+			},
+			"hash":      ack.Hash().String(),
+			"timestamp": a.formatTime(ack.Timestamp),
+			"node":      ack.NodeID,
+		},
+	}
+}
+
 func (a *explorerAPI) formatTime(t time.Time) float64 {
 	return float64(t.UnixNano()) / 1e6
 }
@@ -398,7 +553,9 @@ func (a *explorerAPI) getHash(vars map[string]string) (h *hash.Hash, err error)
 func startAPI(service *Service, listenAddr string) (server *http.Server, err error) {
 	router := mux.NewRouter()
 	router.HandleFunc("/", func(rw http.ResponseWriter, r *http.Request) {
-		sendResponse(http.StatusOK, true, nil, nil, rw)
+		sendResponse(http.StatusOK, true, nil, map[string]interface{}{
+			"version": version,
+		}, rw)
 	}).Methods("GET")
 
 	api := &explorerAPI{
@@ -406,14 +563,20 @@ func startAPI(service *Service, listenAddr string) (server *http.Server, err err
 	}
 	v1Router := router.PathPrefix("/v1").Subrouter()
 	v1Router.HandleFunc("/ack/{db}/{hash}", api.GetAck).Methods("GET")
-	v1Router.HandleFunc("/offset/{db}/{offset:[0-9]+}", api.GetRequestByOffset).Methods("GET")
+	v1Router.HandleFunc("/offset/{db}/{offset:[0-9]+}", notSupported).Methods("GET")
 	v1Router.HandleFunc("/request/{db}/{hash}", api.GetRequest).Methods("GET")
 	v1Router.HandleFunc("/block/{db}/{hash}", api.GetBlock).Methods("GET")
 	v1Router.HandleFunc("/count/{db}/{count:[0-9]+}", api.GetBlockByCount).Methods("GET")
 	v1Router.HandleFunc("/height/{db}/{height:[0-9]+}", api.GetBlockByHeight).Methods("GET")
-	v1Router.HandleFunc("/head/{db}", api.getHighestBlock).Methods("GET")
+	v1Router.HandleFunc("/head/{db}", api.GetHighestBlock).Methods("GET")
 	v2Router := router.PathPrefix("/v2").Subrouter()
-	v2Router.HandleFunc("/head/{db}", api.getHighestBlockV2).Methods("GET")
+	v2Router.HandleFunc("/head/{db}", api.GetHighestBlockV2).Methods("GET")
+	v3Router := router.PathPrefix("/v3").Subrouter()
+	v3Router.HandleFunc("/response/{db}/{hash}", api.GetResponse).Methods("GET")
+	v3Router.HandleFunc("/block/{db}/{hash}", api.GetBlockV3).Methods("GET")
+	v3Router.HandleFunc("/count/{db}/{count:[0-9]+}", api.GetBlockByCountV3).Methods("GET")
+	v3Router.HandleFunc("/height/{db}/{height:[0-9]+}", api.GetBlockByHeightV3).Methods("GET")
+	v3Router.HandleFunc("/head/{db}", api.GetHighestBlockV3).Methods("GET")
 
 	server = &http.Server{
 		Addr:         listenAddr,
diff --git a/cmd/cql-observer/observation_test.go b/cmd/cql-observer/observation_test.go
index 14457edb7..76a1b57c1 100644
--- a/cmd/cql-observer/observation_test.go
+++ b/cmd/cql-observer/observation_test.go
@@ -35,9 +35,9 @@ import (
 	"time"
 
 	"github.com/CovenantSQL/CovenantSQL/client"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 	"github.com/jmoiron/jsonq"
 	. "github.com/smartystreets/goconvey/convey"
 )
@@ -187,7 +187,7 @@ func stopNodes() {
 }
 
 func getJSON(pattern string, args ...interface{}) (result *jsonq.JsonQuery, err error) {
-	url := "http://localhost:4663/v1/" + fmt.Sprintf(pattern, args...)
+	url := "http://localhost:4663/" + fmt.Sprintf(pattern, args...)
 	resp, err := http.Get(url)
 	if err != nil {
 		return
@@ -195,6 +195,15 @@ func getJSON(pattern string, args ...interface{}) (result *jsonq.JsonQuery, err
 
 	var res map[string]interface{}
 	err = json.NewDecoder(resp.Body).Decode(&res)
+	if err != nil {
+		return
+	}
+	log.WithFields(log.Fields{
+		"pattern":  pattern,
+		"args":     args,
+		"response": res,
+		"code":     resp.StatusCode,
+	}).Debug("send test request")
 	result = jsonq.NewQuery(res)
 	success, err := result.Bool("success")
 	if err != nil {
@@ -353,38 +362,41 @@ func TestFullProcess(t *testing.T) {
 		time.Sleep(blockProducePeriod * 2)
 
 		// test get genesis block by height
-		res, err := getJSON("height/%v/0", dbID)
+		res, err := getJSON("v1/height/%v/0", dbID)
 		So(err, ShouldBeNil)
 		So(ensureSuccess(res.Interface("block")), ShouldNotBeNil)
 		So(ensureSuccess(res.Int("block", "height")), ShouldEqual, 0)
 		genesisHash := ensureSuccess(res.String("block", "hash")).(string)
 
 		// test get first containable block
-		res, err = getJSON("height/%v/1", dbID)
+		res, err = getJSON("v3/height/%v/1", dbID)
 		So(err, ShouldBeNil)
 		So(ensureSuccess(res.Interface("block")), ShouldNotBeNil)
 		So(ensureSuccess(res.Int("block", "height")), ShouldEqual, 1)
 		So(ensureSuccess(res.String("block", "hash")), ShouldNotBeEmpty)
 		So(ensureSuccess(res.String("block", "genesis_hash")), ShouldEqual, genesisHash)
-		So(ensureSuccess(res.ArrayOfStrings("block", "queries")), ShouldNotBeEmpty)
+		So(ensureSuccess(res.ArrayOfObjects("block", "queries")), ShouldNotBeEmpty)
 		blockHash := ensureSuccess(res.String("block", "hash")).(string)
 		byHeightBlockResult := ensureSuccess(res.Interface())
 
 		// test get block by hash
-		res, err = getJSON("block/%v/%v", dbID, blockHash)
+		res, err = getJSON("v3/block/%v/%v", dbID, blockHash)
 		So(err, ShouldBeNil)
 		So(ensureSuccess(res.Interface()), ShouldResemble, byHeightBlockResult)
 
+		// test get block by hash using v1 version, returns ack hashes as queries
+		res, err = getJSON("v1/block/%v/%v", dbID, blockHash)
+		So(err, ShouldBeNil)
+
 		ackHashes, err := res.ArrayOfStrings("block", "queries")
 		So(err, ShouldBeNil)
 		So(ackHashes, ShouldNotBeEmpty)
 
 		// test get acked query in block
-		var logOffset int
 		var reqHash string
 
 		for _, ackHash := range ackHashes {
-			res, err = getJSON("ack/%v/%v", dbID, ackHash)
+			res, err = getJSON("v1/ack/%v/%v", dbID, ackHash)
 			So(err, ShouldBeNil)
 			So(ensureSuccess(res.Interface("ack")), ShouldNotBeNil)
 			So(ensureSuccess(res.String("ack", "hash")), ShouldNotBeEmpty)
@@ -393,12 +405,9 @@ func TestFullProcess(t *testing.T) {
 
 			queryType, err := res.String("ack", "request", "type")
 			So(err, ShouldBeNil)
-			So(queryType, ShouldBeIn, []string{wt.WriteQuery.String(), wt.ReadQuery.String()})
+			So(queryType, ShouldBeIn, []string{types.WriteQuery.String(), types.ReadQuery.String()})
 
-			if queryType == wt.WriteQuery.String() {
-				logOffset, err = res.Int("ack", "response", "log_position")
-				So(err, ShouldBeNil)
-				So(logOffset, ShouldBeGreaterThanOrEqualTo, 0)
+			if queryType == types.WriteQuery.String() {
 				reqHash, err = res.String("ack", "request", "hash")
 				So(err, ShouldBeNil)
 				So(reqHash, ShouldNotBeEmpty)
@@ -407,36 +416,24 @@ func TestFullProcess(t *testing.T) {
 
 		// must contains a write query
 		So(reqHash, ShouldNotBeEmpty)
-		So(logOffset, ShouldBeGreaterThanOrEqualTo, 0)
 
 		// test get request entity by request hash
-		res, err = getJSON("request/%v/%v", dbID, reqHash)
+		res, err = getJSON("v1/request/%v/%v", dbID, reqHash)
 		So(err, ShouldBeNil)
 		So(ensureSuccess(res.Interface("request")), ShouldNotBeNil)
 		So(ensureSuccess(res.String("request", "hash")), ShouldNotBeEmpty)
-		So(ensureSuccess(res.String("request", "type")), ShouldEqual, wt.WriteQuery.String())
+		So(ensureSuccess(res.String("request", "type")), ShouldEqual, types.WriteQuery.String())
 		So(ensureSuccess(res.Int("request", "count")), ShouldEqual, 1) // no transaction batch is used
 		So(ensureSuccess(res.ArrayOfObjects("request", "queries")), ShouldNotBeEmpty)
 		So(ensureSuccess(res.String("request", "queries", "0", "pattern")), ShouldNotBeEmpty)
-		byHashRequestResult := ensureSuccess(res.Interface())
-
-		// test get request entity by log offset
-		res, err = getJSON("offset/%v/%v", dbID, logOffset)
-		So(err, ShouldBeNil)
-		So(ensureSuccess(res.Interface()), ShouldResemble, byHashRequestResult)
-
-		// test get first log offset, should be a create table statement
-		res, err = getJSON("offset/%v/0", dbID)
-		So(err, ShouldBeNil)
-		So(ensureSuccess(res.String("request", "queries", "0", "pattern")), ShouldContainSubstring, "CREATE TABLE")
 
 		// test get genesis block by height
-		res, err = getJSON("height/%v/0", dbID2)
+		res, err = getJSON("v3/height/%v/0", dbID2)
 		So(err, ShouldNotBeNil)
 		log.Info(err, res)
 
 		// test get genesis block by height
-		res, err = getJSON("head/%v", dbID2)
+		res, err = getJSON("v3/head/%v", dbID2)
 		So(err, ShouldBeNil)
 		So(ensureSuccess(res.Interface("block")), ShouldNotBeNil)
 		So(ensureSuccess(res.Int("block", "height")), ShouldEqual, 0)
diff --git a/cmd/cql-observer/service.go b/cmd/cql-observer/service.go
index addabbbee..c9fbe25a9 100644
--- a/cmd/cql-observer/service.go
+++ b/cmd/cql-observer/service.go
@@ -25,7 +25,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	bp "github.com/CovenantSQL/CovenantSQL/blockproducer"
 	"github.com/CovenantSQL/CovenantSQL/conf"
 	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
 	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
@@ -33,10 +32,9 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
 	"github.com/CovenantSQL/CovenantSQL/sqlchain"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 	"github.com/coreos/bbolt"
 )
 
@@ -57,20 +55,20 @@ const (
   |    |                  \--> [count] => height
   |    |
   |  [block]-->[`dbID`]
-  |    |          |---> [height+hash] => block
-  |    |           \--> [height+hash] => block
+  |    |          |---> [height+hash+count] => block
+  |    |           \--> [height+hash+count] => block
   |    |
   |  [ack]-->[`dbID`]
-  |    |	    |---> [hash] => ack
-  |    |         \--> [hash] => ack
+  |    |	    |---> [hash] => height+offset
+  |    |         \--> [hash] => height+offset
   |    |
   |  [request]-->[`dbID`]
-  |    |            |---> [offset+hash] => request
-  |    |             \--> [offset+hash] => request
+  |    |            |---> [hash] => height+offset
+  |    |             \--> [hash] => height+offset
   |    |
-  |  [offset]-->[`dbID`]
-  |                 |---> [hash] => offset
-  |                  \--> [hash] => offset
+  |  [response]-->[`dbID`]
+  |                 |---> [hash] => height+offset
+  |                  \--> [hash] => height+offset
   |
    \-> [subscription]
              \---> [`dbID`] => height
@@ -81,16 +79,18 @@ var (
 	ErrStopped = errors.New("observer service has stopped")
 	// ErrNotFound defines error on fail to found specified resource
 	ErrNotFound = errors.New("resource not found")
+	// ErrInconsistentData represents corrupted observation data.
+	ErrInconsistentData = errors.New("inconsistent data")
 
 	// bolt db buckets
 	blockBucket             = []byte("block")
 	blockCount2HeightBucket = []byte("block-count-to-height")
 	ackBucket               = []byte("ack")
 	requestBucket           = []byte("request")
+	responseBucket          = []byte("response")
 	subscriptionBucket      = []byte("subscription")
 
 	blockHeightBucket = []byte("height")
-	logOffsetBucket   = []byte("offset")
 
 	// blockProducePeriod defines the block producing interval
 	blockProducePeriod = 60 * time.Second
@@ -142,7 +142,7 @@ func NewService() (service *Service, err error) {
 		if _, err = tx.CreateBucketIfNotExists(blockHeightBucket); err != nil {
 			return
 		}
-		_, err = tx.CreateBucketIfNotExists(logOffsetBucket)
+		_, err = tx.CreateBucketIfNotExists(responseBucket)
 		return
 	}); err != nil {
 		return
@@ -170,16 +170,6 @@ func NewService() (service *Service, err error) {
 	return
 }
 
-func offsetToBytes(offset uint64) (data []byte) {
-	data = make([]byte, 8)
-	binary.BigEndian.PutUint64(data, offset)
-	return
-}
-
-func bytesToOffset(data []byte) uint64 {
-	return uint64(binary.BigEndian.Uint64(data))
-}
-
 func int32ToBytes(h int32) (data []byte) {
 	data = make([]byte, 4)
 	binary.BigEndian.PutUint32(data, uint32(h))
@@ -204,11 +194,11 @@ func (s *Service) subscribe(dbID proto.DatabaseID, resetSubscribePosition string
 
 		switch resetSubscribePosition {
 		case "newest":
-			fromPos = ct.ReplicateFromNewest
+			fromPos = types.ReplicateFromNewest
 		case "oldest":
-			fromPos = ct.ReplicateFromBeginning
+			fromPos = types.ReplicateFromBeginning
 		default:
-			fromPos = ct.ReplicateFromNewest
+			fromPos = types.ReplicateFromNewest
 		}
 
 		s.subscription[dbID] = fromPos
@@ -219,7 +209,7 @@ func (s *Service) subscribe(dbID proto.DatabaseID, resetSubscribePosition string
 	} else {
 		// not resetting
 		if _, exists := s.subscription[dbID]; !exists {
-			s.subscription[dbID] = ct.ReplicateFromNewest
+			s.subscription[dbID] = types.ReplicateFromNewest
 			shouldStartSubscribe = true
 		}
 	}
@@ -253,21 +243,6 @@ func (s *Service) AdviseNewBlock(req *sqlchain.MuxAdviseNewBlockReq, resp *sqlch
 	return s.addBlock(req.DatabaseID, req.Count, req.Block)
 }
 
-// AdviseAckedQuery handles acked query replication request from the remote database chain service.
-func (s *Service) AdviseAckedQuery(req *sqlchain.MuxAdviseAckedQueryReq, resp *sqlchain.MuxAdviseAckedQueryResp) (err error) {
-	if atomic.LoadInt32(&s.stopped) == 1 {
-		// stopped
-		return ErrStopped
-	}
-
-	if req.Query == nil {
-		log.WithField("node", req.GetNodeID().String()).Info("received empty acked query")
-		return
-	}
-
-	return s.addAckedQuery(req.DatabaseID, req.Query)
-}
-
 func (s *Service) start() (err error) {
 	if atomic.LoadInt32(&s.stopped) == 1 {
 		// stopped
@@ -322,11 +297,12 @@ func (s *Service) startSubscribe(dbID proto.DatabaseID) (err error) {
 	return
 }
 
-func (s *Service) addAckedQuery(dbID proto.DatabaseID, ack *wt.SignedAckHeader) (err error) {
+func (s *Service) addAck(dbID proto.DatabaseID, height int32, offset int32, ack *types.SignedAckHeader) (err error) {
 	log.WithFields(log.Fields{
-		"ack": ack.Hash.String(),
-		"db":  dbID,
-	}).Debug("add ack query")
+		"height": height,
+		"ack":    ack.Hash().String(),
+		"db":     dbID,
+	}).Debug("add ack")
 
 	if atomic.LoadInt32(&s.stopped) == 1 {
 		// stopped
@@ -340,71 +316,62 @@ func (s *Service) addAckedQuery(dbID proto.DatabaseID, ack *wt.SignedAckHeader)
 		return
 	}
 
-	// fetch original query
-	if ack.Response.Request.QueryType == wt.WriteQuery {
-		req := &wt.GetRequestReq{}
-		resp := &wt.GetRequestResp{}
-
-		req.DatabaseID = dbID
-		req.LogOffset = ack.Response.LogOffset
-
-		if err = s.minerRequest(dbID, route.DBSGetRequest.String(), req, resp); err != nil {
+	// store ack
+	return s.db.Update(func(tx *bolt.Tx) (err error) {
+		ab, err := tx.Bucket(ackBucket).CreateBucketIfNotExists([]byte(dbID))
+		if err != nil {
 			return
 		}
+		err = ab.Put(ack.Hash().AsBytes(), utils.ConcatAll(int32ToBytes(height), int32ToBytes(offset)))
+		return
+	})
+}
 
-		key := offsetToBytes(req.LogOffset)
-		key = append(key, resp.Request.Header.Hash.CloneBytes()...)
+func (s *Service) addQueryTracker(dbID proto.DatabaseID, height int32, offset int32, qt *types.QueryAsTx) (err error) {
+	log.WithFields(log.Fields{
+		"req":  qt.Request.Header.Hash(),
+		"resp": qt.Response.Hash(),
+	}).Debug("add query tracker")
 
-		log.WithFields(log.Fields{
-			"offset":     req.LogOffset,
-			"reqHash":    resp.Request.Header.Hash.String(),
-			"reqQueries": resp.Request.Payload.Queries,
-		}).Debug("add write request")
+	if atomic.LoadInt32(&s.stopped) == 1 {
+		// stopped
+		return ErrStopped
+	}
 
-		var reqBytes *bytes.Buffer
-		if reqBytes, err = utils.EncodeMsgPack(resp.Request); err != nil {
-			return
-		}
+	s.lock.Lock()
+	defer s.lock.Unlock()
 
-		if err = s.db.Update(func(tx *bolt.Tx) (err error) {
-			qb, err := tx.Bucket(requestBucket).CreateBucketIfNotExists([]byte(dbID))
-			if err != nil {
-				return
-			}
-			if err = qb.Put(key, reqBytes.Bytes()); err != nil {
-				return
-			}
-			ob, err := tx.Bucket(logOffsetBucket).CreateBucketIfNotExists([]byte(dbID))
-			if err != nil {
-				return
-			}
-			err = ob.Put(resp.Request.Header.Hash.CloneBytes(), offsetToBytes(req.LogOffset))
-			return
-		}); err != nil {
-			return
-		}
+	if err = qt.Request.Verify(); err != nil {
+		return
+	}
+	if err = qt.Response.Verify(); err != nil {
+		return
 	}
 
-	// store ack
+	dataBytes := utils.ConcatAll(int32ToBytes(height), int32ToBytes(offset))
+
+	// store request and response
 	return s.db.Update(func(tx *bolt.Tx) (err error) {
-		ab, err := tx.Bucket(ackBucket).CreateBucketIfNotExists([]byte(dbID))
+		reqb, err := tx.Bucket(requestBucket).CreateBucketIfNotExists([]byte(dbID))
 		if err != nil {
 			return
 		}
-		ackBytes, err := utils.EncodeMsgPack(ack)
+		resb, err := tx.Bucket(responseBucket).CreateBucketIfNotExists([]byte(dbID))
 		if err != nil {
 			return
 		}
-		err = ab.Put(ack.Hash.CloneBytes(), ackBytes.Bytes())
+		if err = reqb.Put(qt.Request.Header.Hash().AsBytes(), dataBytes); err != nil {
+			return
+		}
+		err = resb.Put(qt.Response.Hash().AsBytes(), dataBytes)
 		return
 	})
 }
 
-func (s *Service) addBlock(dbID proto.DatabaseID, count int32, b *ct.Block) (err error) {
+func (s *Service) addBlock(dbID proto.DatabaseID, count int32, b *types.Block) (err error) {
 	instance, err := s.getUpstream(dbID)
 	h := int32(b.Timestamp().Sub(instance.GenesisBlock.Timestamp()) / blockProducePeriod)
-	key := int32ToBytes(h)
-	key = append(key, b.BlockHash().CloneBytes()...)
+	key := utils.ConcatAll(int32ToBytes(h), b.BlockHash().AsBytes(), int32ToBytes(count))
 	// It's actually `countToBytes`
 	ckey := int32ToBytes(count)
 	blockBytes, err := utils.EncodeMsgPack(b)
@@ -416,9 +383,10 @@ func (s *Service) addBlock(dbID proto.DatabaseID, count int32, b *ct.Block) (err
 		"count":    count,
 		"height":   h,
 		"producer": b.Producer(),
+		"block":    b,
 	}).Debugf("Add new block %v -> %v", b.BlockHash(), b.ParentHash())
 
-	return s.db.Update(func(tx *bolt.Tx) (err error) {
+	if err = s.db.Update(func(tx *bolt.Tx) (err error) {
 		bb, err := tx.Bucket(blockBucket).CreateBucketIfNotExists([]byte(dbID))
 		if err != nil {
 			return
@@ -431,7 +399,7 @@ func (s *Service) addBlock(dbID proto.DatabaseID, count int32, b *ct.Block) (err
 			return
 		}
 		if count >= 0 {
-			if err = cb.Put(ckey, key); err != nil {
+			if err = cb.Put(ckey, int32ToBytes(h)); err != nil {
 				return
 			}
 		}
@@ -441,7 +409,25 @@ func (s *Service) addBlock(dbID proto.DatabaseID, count int32, b *ct.Block) (err
 		}
 		err = hb.Put(b.BlockHash()[:], int32ToBytes(h))
 		return
-	})
+	}); err != nil {
+		return
+	}
+
+	// save ack
+	for i, q := range b.Acks {
+		if err = s.addAck(dbID, h, int32(i), q); err != nil {
+			return
+		}
+	}
+
+	// save queries
+	for i, q := range b.QueryTxs {
+		if err = s.addQueryTracker(dbID, h, int32(i), q); err != nil {
+			return
+		}
+	}
+
+	return
 }
 
 func (s *Service) stop() (err error) {
@@ -483,11 +469,11 @@ func (s *Service) minerRequest(dbID proto.DatabaseID, method string, request int
 	return s.caller.CallNode(instance.Peers.Leader, method, request, response)
 }
 
-func (s *Service) getUpstream(dbID proto.DatabaseID) (instance *wt.ServiceInstance, err error) {
+func (s *Service) getUpstream(dbID proto.DatabaseID) (instance *types.ServiceInstance, err error) {
 	log.WithField("db", dbID).Info("get peers info for database")
 
 	if iInstance, exists := s.upstreamServers.Load(dbID); exists {
-		instance = iInstance.(*wt.ServiceInstance)
+		instance = iInstance.(*types.ServiceInstance)
 		return
 	}
 
@@ -501,12 +487,12 @@ func (s *Service) getUpstream(dbID proto.DatabaseID) (instance *wt.ServiceInstan
 		return
 	}
 
-	req := &bp.GetDatabaseRequest{}
+	req := &types.GetDatabaseRequest{}
 	req.Header.DatabaseID = dbID
 	if err = req.Sign(privateKey); err != nil {
 		return
 	}
-	resp := &bp.GetDatabaseResponse{}
+	resp := &types.GetDatabaseResponse{}
 	// get peers list from block producer
 	if err = s.caller.CallNode(curBP, route.BPDBGetDatabase.String(), req, resp); err != nil {
 		return
@@ -521,81 +507,167 @@ func (s *Service) getUpstream(dbID proto.DatabaseID) (instance *wt.ServiceInstan
 	return
 }
 
-func (s *Service) getAck(dbID proto.DatabaseID, h *hash.Hash) (ack *wt.SignedAckHeader, err error) {
-	err = s.db.View(func(tx *bolt.Tx) error {
+func (s *Service) getAck(dbID proto.DatabaseID, h *hash.Hash) (ack *types.SignedAckHeader, err error) {
+	var (
+		blockHeight int32
+		dataOffset  int32
+	)
+
+	if err = s.db.View(func(tx *bolt.Tx) (err error) {
 		bucket := tx.Bucket(ackBucket).Bucket([]byte(dbID))
 
 		if bucket == nil {
 			return ErrNotFound
 		}
 
-		ackBytes := bucket.Get(h.CloneBytes())
+		ackBytes := bucket.Get(h.AsBytes())
 		if ackBytes == nil {
 			return ErrNotFound
 		}
 
-		return utils.DecodeMsgPack(ackBytes, &ack)
-	})
+		// get block height and object offset in block
+		if len(ackBytes) != 8 {
+			// invalid data payload
+			return ErrInconsistentData
+		}
+
+		blockHeight = bytesToInt32(ackBytes[:4])
+		dataOffset = bytesToInt32(ackBytes[4:])
+
+		return
+	}); err != nil {
+		return
+	}
+
+	// get data from block
+	var b *types.Block
+	if _, b, err = s.getBlockByHeight(dbID, blockHeight); err != nil {
+		return
+	}
+
+	if dataOffset < 0 || int32(len(b.Acks)) <= dataOffset {
+		err = ErrInconsistentData
+		return
+	}
+
+	ack = b.Acks[int(dataOffset)]
+
+	// verify hash
+	ackHash := ack.Hash()
+	if !ackHash.IsEqual(h) {
+		err = ErrInconsistentData
+	}
 
 	return
 }
 
-func (s *Service) getRequest(dbID proto.DatabaseID, h *hash.Hash) (request *wt.Request, err error) {
-	err = s.db.View(func(tx *bolt.Tx) error {
-		bucket := tx.Bucket(logOffsetBucket).Bucket([]byte(dbID))
+func (s *Service) getRequest(dbID proto.DatabaseID, h *hash.Hash) (request *types.Request, err error) {
+	var (
+		blockHeight int32
+		dataOffset  int32
+	)
 
+	if err = s.db.View(func(tx *bolt.Tx) (err error) {
+		bucket := tx.Bucket(requestBucket).Bucket([]byte(dbID))
 		if bucket == nil {
 			return ErrNotFound
 		}
 
-		reqKey := bucket.Get(h.CloneBytes())
-		if reqKey == nil {
+		reqBytes := bucket.Get(h.AsBytes())
+		if reqBytes == nil {
 			return ErrNotFound
 		}
 
-		reqKey = append([]byte{}, reqKey...)
-		reqKey = append(reqKey, h.CloneBytes()...)
-
-		bucket = tx.Bucket(requestBucket).Bucket([]byte(dbID))
-		if bucket == nil {
-			return ErrNotFound
+		// get block height and object offset in block
+		if len(reqBytes) != 8 {
+			// invalid data payload
+			return ErrInconsistentData
 		}
 
-		reqBytes := bucket.Get(reqKey)
-		if reqBytes == nil {
-			return ErrNotFound
-		}
+		blockHeight = bytesToInt32(reqBytes[:4])
+		dataOffset = bytesToInt32(reqBytes[4:])
 
-		return utils.DecodeMsgPack(reqBytes, &request)
-	})
+		return
+	}); err != nil {
+		return
+	}
+
+	// get data from block
+	var b *types.Block
+	if _, b, err = s.getBlockByHeight(dbID, blockHeight); err != nil {
+		return
+	}
+
+	if dataOffset < 0 || int32(len(b.QueryTxs)) <= dataOffset {
+		err = ErrInconsistentData
+		return
+	}
+
+	request = b.QueryTxs[int(dataOffset)].Request
+
+	// verify hash
+	reqHash := request.Header.Hash()
+	if !reqHash.IsEqual(h) {
+		err = ErrInconsistentData
+	}
 
 	return
 }
 
-func (s *Service) getRequestByOffset(dbID proto.DatabaseID, offset uint64) (request *wt.Request, err error) {
-	err = s.db.View(func(tx *bolt.Tx) error {
-		bucket := tx.Bucket(requestBucket).Bucket([]byte(dbID))
+func (s *Service) getResponseHeader(dbID proto.DatabaseID, h *hash.Hash) (response *types.SignedResponseHeader, err error) {
+	var (
+		blockHeight int32
+		dataOffset  int32
+	)
 
+	if err = s.db.View(func(tx *bolt.Tx) (err error) {
+		bucket := tx.Bucket(requestBucket).Bucket([]byte(dbID))
 		if bucket == nil {
 			return ErrNotFound
 		}
 
-		keyPrefix := offsetToBytes(offset)
-		cur := bucket.Cursor()
+		respBytes := bucket.Get(h.AsBytes())
+		if respBytes == nil {
+			return ErrNotFound
+		}
 
-		for k, v := cur.Seek(keyPrefix); k != nil && bytes.HasPrefix(k, keyPrefix); k, v = cur.Next() {
-			if v != nil {
-				return utils.DecodeMsgPack(v, &request)
-			}
+		// get block height and object offset in block
+		if len(respBytes) != 8 {
+			// invalid data payload
+			return ErrInconsistentData
 		}
 
-		return ErrNotFound
-	})
+		blockHeight = bytesToInt32(respBytes[:4])
+		dataOffset = bytesToInt32(respBytes[4:])
+
+		return
+	}); err != nil {
+		return
+	}
+
+	// get data from block
+	var b *types.Block
+	if _, b, err = s.getBlockByHeight(dbID, blockHeight); err != nil {
+		return
+	}
+
+	if dataOffset < 0 || int32(len(b.QueryTxs)) <= dataOffset {
+		err = ErrInconsistentData
+		return
+	}
+
+	response = b.QueryTxs[int(dataOffset)].Response
+
+	// verify hash
+	respHash := response.Hash()
+	if !respHash.IsEqual(h) {
+		err = ErrInconsistentData
+	}
 
 	return
 }
 
-func (s *Service) getHighestBlock(dbID proto.DatabaseID) (height int32, b *ct.Block, err error) {
+func (s *Service) getHighestBlock(dbID proto.DatabaseID) (height int32, b *types.Block, err error) {
 	err = s.db.View(func(tx *bolt.Tx) error {
 		bucket := tx.Bucket(blockBucket).Bucket([]byte(dbID))
 
@@ -617,7 +689,7 @@ func (s *Service) getHighestBlock(dbID proto.DatabaseID) (height int32, b *ct.Bl
 }
 
 func (s *Service) getHighestBlockV2(
-	dbID proto.DatabaseID) (count, height int32, b *ct.Block, err error,
+	dbID proto.DatabaseID) (count, height int32, b *types.Block, err error,
 ) {
 	err = s.db.View(func(tx *bolt.Tx) (err error) {
 		var (
@@ -651,7 +723,7 @@ func (s *Service) getHighestBlockV2(
 	return
 }
 
-func (s *Service) getBlockByHeight(dbID proto.DatabaseID, height int32) (b *ct.Block, err error) {
+func (s *Service) getBlockByHeight(dbID proto.DatabaseID, height int32) (count int32, b *types.Block, err error) {
 	err = s.db.View(func(tx *bolt.Tx) error {
 		bucket := tx.Bucket(blockBucket).Bucket([]byte(dbID))
 
@@ -664,6 +736,10 @@ func (s *Service) getBlockByHeight(dbID proto.DatabaseID, height int32) (b *ct.B
 		cur := bucket.Cursor()
 		for k, v := cur.Seek(keyPrefix); k != nil && bytes.HasPrefix(k, keyPrefix); k, v = cur.Next() {
 			if v != nil {
+				if len(k) < 4+hash.HashSize+4 {
+					return ErrInconsistentData
+				}
+				count = bytesToInt32(k[4+hash.HashSize:])
 				return utils.DecodeMsgPack(v, &b)
 			}
 		}
@@ -675,7 +751,7 @@ func (s *Service) getBlockByHeight(dbID proto.DatabaseID, height int32) (b *ct.B
 }
 
 func (s *Service) getBlockByCount(
-	dbID proto.DatabaseID, count int32) (height int32, b *ct.Block, err error,
+	dbID proto.DatabaseID, count int32) (height int32, b *types.Block, err error,
 ) {
 	err = s.db.View(func(tx *bolt.Tx) (err error) {
 		var (
@@ -709,7 +785,7 @@ func (s *Service) getBlockByCount(
 	return
 }
 
-func (s *Service) getBlock(dbID proto.DatabaseID, h *hash.Hash) (height int32, b *ct.Block, err error) {
+func (s *Service) getBlock(dbID proto.DatabaseID, h *hash.Hash) (count int32, height int32, b *types.Block, err error) {
 	err = s.db.View(func(tx *bolt.Tx) error {
 		bucket := tx.Bucket(blockHeightBucket).Bucket([]byte(dbID))
 
@@ -717,37 +793,45 @@ func (s *Service) getBlock(dbID proto.DatabaseID, h *hash.Hash) (height int32, b
 			return ErrNotFound
 		}
 
-		blockKey := bucket.Get(h.CloneBytes())
-		if blockKey == nil {
+		blockKeyPrefix := bucket.Get(h.AsBytes())
+		if blockKeyPrefix == nil {
 			return ErrNotFound
 		}
 
-		blockKey = append([]byte{}, blockKey...)
-		blockKey = append(blockKey, h.CloneBytes()...)
+		blockKeyPrefix = append([]byte{}, blockKeyPrefix...)
+		blockKeyPrefix = append(blockKeyPrefix, h.AsBytes()...)
 
 		bucket = tx.Bucket(blockBucket).Bucket([]byte(dbID))
 		if bucket == nil {
 			return ErrNotFound
 		}
 
-		blockBytes := bucket.Get(blockKey)
+		var (
+			blockKey   []byte
+			blockBytes []byte
+		)
+
+		cur := bucket.Cursor()
+		for blockKey, blockBytes = cur.Seek(blockKeyPrefix); blockKey != nil && bytes.HasPrefix(blockKey, blockKeyPrefix); blockKey, blockBytes = cur.Next() {
+			if blockBytes != nil {
+				break
+			}
+		}
+
 		if blockBytes == nil {
 			return ErrNotFound
 		}
 
-		return utils.DecodeMsgPack(blockBytes, &b)
-	})
-
-	if err == nil {
-		// compute height
-		var instance *wt.ServiceInstance
-		instance, err = s.getUpstream(dbID)
-		if err != nil {
-			return
+		// decode count from block key
+		if len(blockKey) < 4+hash.HashSize+4 {
+			return ErrInconsistentData
 		}
 
-		height = int32(b.Timestamp().Sub(instance.GenesisBlock.Timestamp()) / blockProducePeriod)
-	}
+		height = bytesToInt32(blockKey[:4])
+		count = bytesToInt32(blockKey[4+hash.HashSize:])
+
+		return utils.DecodeMsgPack(blockBytes, &b)
+	})
 
 	return
 }
diff --git a/cmd/cql/main.go b/cmd/cql/main.go
index 5ec683a4c..91791193e 100644
--- a/cmd/cql/main.go
+++ b/cmd/cql/main.go
@@ -29,9 +29,6 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/CovenantSQL/CovenantSQL/client"
-	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
-	"github.com/CovenantSQL/CovenantSQL/utils/log"
 	"github.com/CovenantSQL/go-sqlite3-encrypt"
 	"github.com/xo/dburl"
 	"github.com/xo/usql/drivers"
@@ -39,6 +36,10 @@ import (
 	"github.com/xo/usql/handler"
 	"github.com/xo/usql/rline"
 	"github.com/xo/usql/text"
+
+	"github.com/CovenantSQL/CovenantSQL/client"
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
 )
 
 const name = "cql"
@@ -220,8 +221,8 @@ func main() {
 			return
 		}
 
-		log.Infof("stable coin balance is: %#v", stableCoinBalance)
-		log.Infof("covenant coin balance is: %#v", covenantCoinBalance)
+		log.Infof("stable coin balance is: %d", stableCoinBalance)
+		log.Infof("covenant coin balance is: %d", covenantCoinBalance)
 
 		return
 	}
diff --git a/cmd/cqld/adapter.go b/cmd/cqld/adapter.go
index 41427b8b9..eec701a13 100644
--- a/cmd/cqld/adapter.go
+++ b/cmd/cqld/adapter.go
@@ -29,10 +29,10 @@ import (
 	kt "github.com/CovenantSQL/CovenantSQL/kayak/types"
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
-	"github.com/CovenantSQL/CovenantSQL/sqlchain/storage"
+	"github.com/CovenantSQL/CovenantSQL/storage"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 	"github.com/pkg/errors"
 )
 
@@ -182,7 +182,7 @@ func (s *LocalStorage) compileLog(payload *KayakPayload) (result *compiledLog, e
 			nodeToSet: &nodeToSet,
 		}
 	case CmdSetDatabase:
-		var instance wt.ServiceInstance
+		var instance types.ServiceInstance
 		if err = utils.DecodeMsgPack(payload.Data, &instance); err != nil {
 			log.WithError(err).Error("compileLog: unmarshal instance meta failed")
 			return
@@ -201,7 +201,7 @@ func (s *LocalStorage) compileLog(payload *KayakPayload) (result *compiledLog, e
 			},
 		}
 	case CmdDeleteDatabase:
-		var instance wt.ServiceInstance
+		var instance types.ServiceInstance
 		if err = utils.DecodeMsgPack(payload.Data, &instance); err != nil {
 			log.WithError(err).Error("compileLog: unmarshal instance id failed")
 			return
@@ -294,7 +294,7 @@ func (s *KayakKVServer) Reset() (err error) {
 }
 
 // GetDatabase implements blockproducer.DBMetaPersistence.
-func (s *KayakKVServer) GetDatabase(dbID proto.DatabaseID) (instance wt.ServiceInstance, err error) {
+func (s *KayakKVServer) GetDatabase(dbID proto.DatabaseID) (instance types.ServiceInstance, err error) {
 	var result [][]interface{}
 	query := "SELECT `meta` FROM `databases` WHERE `id` = ? LIMIT 1"
 	_, _, result, err = s.KVStorage.Query(context.Background(), []storage.Query{
@@ -327,7 +327,7 @@ func (s *KayakKVServer) GetDatabase(dbID proto.DatabaseID) (instance wt.ServiceI
 }
 
 // SetDatabase implements blockproducer.DBMetaPersistence.
-func (s *KayakKVServer) SetDatabase(meta wt.ServiceInstance) (err error) {
+func (s *KayakKVServer) SetDatabase(meta types.ServiceInstance) (err error) {
 	var metaBuf *bytes.Buffer
 	if metaBuf, err = utils.EncodeMsgPack(meta); err != nil {
 		return
@@ -348,7 +348,7 @@ func (s *KayakKVServer) SetDatabase(meta wt.ServiceInstance) (err error) {
 
 // DeleteDatabase implements blockproducer.DBMetaPersistence.
 func (s *KayakKVServer) DeleteDatabase(dbID proto.DatabaseID) (err error) {
-	meta := wt.ServiceInstance{
+	meta := types.ServiceInstance{
 		DatabaseID: dbID,
 	}
 
@@ -370,7 +370,7 @@ func (s *KayakKVServer) DeleteDatabase(dbID proto.DatabaseID) (err error) {
 }
 
 // GetAllDatabases implements blockproducer.DBMetaPersistence.
-func (s *KayakKVServer) GetAllDatabases() (instances []wt.ServiceInstance, err error) {
+func (s *KayakKVServer) GetAllDatabases() (instances []types.ServiceInstance, err error) {
 	var result [][]interface{}
 	query := "SELECT `meta` FROM `databases`"
 	_, _, result, err = s.KVStorage.Query(context.Background(), []storage.Query{
@@ -383,14 +383,14 @@ func (s *KayakKVServer) GetAllDatabases() (instances []wt.ServiceInstance, err e
 		return
 	}
 
-	instances = make([]wt.ServiceInstance, 0, len(result))
+	instances = make([]types.ServiceInstance, 0, len(result))
 
 	for _, row := range result {
 		if len(row) <= 0 {
 			continue
 		}
 
-		var instance wt.ServiceInstance
+		var instance types.ServiceInstance
 		var rawInstanceMeta []byte
 		var ok bool
 		if rawInstanceMeta, ok = row[0].([]byte); !ok {
diff --git a/cmd/cqld/bootstrap.go b/cmd/cqld/bootstrap.go
index b2c052c3d..ef0ed00c5 100644
--- a/cmd/cqld/bootstrap.go
+++ b/cmd/cqld/bootstrap.go
@@ -154,8 +154,8 @@ func runNode(nodeID proto.NodeID, listenAddr string) (err error) {
 		server,
 		peers,
 		nodeID,
-		2*time.Second,
-		900*time.Millisecond,
+		time.Minute,
+		20*time.Second,
 	)
 	chain, err := bp.NewChain(chainConfig)
 	if err != nil {
diff --git a/cmd/hotfix/hash-upgrade/main.go b/cmd/hotfix/hash-upgrade/main.go
index 1c534a00d..7e4e89a93 100644
--- a/cmd/hotfix/hash-upgrade/main.go
+++ b/cmd/hotfix/hash-upgrade/main.go
@@ -31,11 +31,11 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
 	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
 	"github.com/CovenantSQL/CovenantSQL/proto"
-	"github.com/CovenantSQL/CovenantSQL/sqlchain/storage"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/otypes"
+	"github.com/CovenantSQL/CovenantSQL/storage"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
+	wt "github.com/CovenantSQL/CovenantSQL/worker/otypes"
 )
 
 var (
diff --git a/cmd/hotfix/observer-upgrade/main.go b/cmd/hotfix/observer-upgrade/main.go
index 137b8aaf6..c650f306d 100644
--- a/cmd/hotfix/observer-upgrade/main.go
+++ b/cmd/hotfix/observer-upgrade/main.go
@@ -23,7 +23,7 @@ import (
 	"os"
 
 	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/otypes"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
 	"github.com/coreos/bbolt"
diff --git a/crypto/asymmetric/signature.go b/crypto/asymmetric/signature.go
index 77ac14580..ec7e59804 100644
--- a/crypto/asymmetric/signature.go
+++ b/crypto/asymmetric/signature.go
@@ -96,6 +96,9 @@ func (s *Signature) Verify(hash []byte, signee *PublicKey) bool {
 	if BypassSignature {
 		return true
 	}
+	if signee == nil || s == nil {
+		return false
+	}
 
 	signature := make([]byte, 64)
 	copy(signature, utils.PaddedBigBytes(s.R, 32))
diff --git a/crypto/hash/hash.go b/crypto/hash/hash.go
index 8108e9f3e..74b9e49e4 100644
--- a/crypto/hash/hash.go
+++ b/crypto/hash/hash.go
@@ -48,6 +48,11 @@ func (h Hash) String() string {
 	return hex.EncodeToString(h[:])
 }
 
+// AsBytes returns internal bytes of hash.
+func (h Hash) AsBytes() []byte {
+	return h[:]
+}
+
 // CloneBytes returns a copy of the bytes which represent the hash as a byte
 // slice.
 //
diff --git a/crypto/verifier/common.go b/crypto/verifier/common.go
new file mode 100644
index 000000000..41fa8ecb4
--- /dev/null
+++ b/crypto/verifier/common.go
@@ -0,0 +1,83 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package verifier
+
+import (
+	ca "github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/pkg/errors"
+)
+
+//go:generate hsp
+
+// MarshalHasher is the interface implemented by an object that can be stably marshalling hashed.
+type MarshalHasher interface {
+	MarshalHash() ([]byte, error)
+}
+
+// HashSignVerifier is the interface implemented by an object that contains a hash value of an
+// MarshalHasher, can be signed by a private key and verified later.
+type HashSignVerifier interface {
+	Hash() hash.Hash
+	Sign(MarshalHasher, *ca.PrivateKey) error
+	Verify(MarshalHasher) error
+}
+
+// DefaultHashSignVerifierImpl defines a default implementation of HashSignVerifier.
+type DefaultHashSignVerifierImpl struct {
+	DataHash  hash.Hash
+	Signee    *ca.PublicKey
+	Signature *ca.Signature
+}
+
+// Hash implements HashSignVerifier.Hash.
+func (i *DefaultHashSignVerifierImpl) Hash() hash.Hash {
+	return i.DataHash
+}
+
+// Sign implements HashSignVerifier.Sign.
+func (i *DefaultHashSignVerifierImpl) Sign(mh MarshalHasher, signer *ca.PrivateKey) (err error) {
+	var enc []byte
+	if enc, err = mh.MarshalHash(); err != nil {
+		return
+	}
+	var h = hash.THashH(enc)
+	if i.Signature, err = signer.Sign(h[:]); err != nil {
+		return
+	}
+	i.DataHash = h
+	i.Signee = signer.PubKey()
+	return
+}
+
+// Verify implements HashSignVerifier.Verify.
+func (i *DefaultHashSignVerifierImpl) Verify(mh MarshalHasher) (err error) {
+	var enc []byte
+	if enc, err = mh.MarshalHash(); err != nil {
+		return
+	}
+	var h = hash.THashH(enc)
+	if !i.DataHash.IsEqual(&h) {
+		err = errors.WithStack(ErrHashValueNotMatch)
+		return
+	}
+	if !i.Signature.Verify(h[:], i.Signee) {
+		err = errors.WithStack(ErrSignatureNotMatch)
+		return
+	}
+	return
+}
diff --git a/crypto/verifier/common_gen.go b/crypto/verifier/common_gen.go
new file mode 100644
index 000000000..943ac0eda
--- /dev/null
+++ b/crypto/verifier/common_gen.go
@@ -0,0 +1,59 @@
+package verifier
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	hsp "github.com/CovenantSQL/HashStablePack/marshalhash"
+)
+
+// MarshalHash marshals for hash
+func (z *DefaultHashSignVerifierImpl) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 3
+	o = append(o, 0x83, 0x83)
+	if z.Signee == nil {
+		o = hsp.AppendNil(o)
+	} else {
+		if oTemp, err := z.Signee.MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	o = append(o, 0x83)
+	if z.Signature == nil {
+		o = hsp.AppendNil(o)
+	} else {
+		if oTemp, err := z.Signature.MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	o = append(o, 0x83)
+	if oTemp, err := z.DataHash.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *DefaultHashSignVerifierImpl) Msgsize() (s int) {
+	s = 1 + 7
+	if z.Signee == nil {
+		s += hsp.NilSize
+	} else {
+		s += z.Signee.Msgsize()
+	}
+	s += 10
+	if z.Signature == nil {
+		s += hsp.NilSize
+	} else {
+		s += z.Signature.Msgsize()
+	}
+	s += 9 + z.DataHash.Msgsize()
+	return
+}
diff --git a/chain/xxx_gen_test_test.go b/crypto/verifier/common_gen_test.go
similarity index 66%
rename from chain/xxx_gen_test_test.go
rename to crypto/verifier/common_gen_test.go
index 04c1be79d..4f73911c7 100644
--- a/chain/xxx_gen_test_test.go
+++ b/crypto/verifier/common_gen_test.go
@@ -1,4 +1,4 @@
-package chain
+package verifier
 
 // Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
 
@@ -9,8 +9,8 @@ import (
 	"testing"
 )
 
-func TestMarshalHashDemoHeader(t *testing.T) {
-	v := DemoHeader{}
+func TestMarshalHashDefaultHashSignVerifierImpl(t *testing.T) {
+	v := DefaultHashSignVerifierImpl{}
 	binary.Read(rand.Reader, binary.BigEndian, &v)
 	bts1, err := v.MarshalHash()
 	if err != nil {
@@ -25,8 +25,8 @@ func TestMarshalHashDemoHeader(t *testing.T) {
 	}
 }
 
-func BenchmarkMarshalHashDemoHeader(b *testing.B) {
-	v := DemoHeader{}
+func BenchmarkMarshalHashDefaultHashSignVerifierImpl(b *testing.B) {
+	v := DefaultHashSignVerifierImpl{}
 	b.ReportAllocs()
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
@@ -34,8 +34,8 @@ func BenchmarkMarshalHashDemoHeader(b *testing.B) {
 	}
 }
 
-func BenchmarkAppendMsgDemoHeader(b *testing.B) {
-	v := DemoHeader{}
+func BenchmarkAppendMsgDefaultHashSignVerifierImpl(b *testing.B) {
+	v := DefaultHashSignVerifierImpl{}
 	bts := make([]byte, 0, v.Msgsize())
 	bts, _ = v.MarshalHash()
 	b.SetBytes(int64(len(bts)))
diff --git a/crypto/verifier/common_test.go b/crypto/verifier/common_test.go
new file mode 100644
index 000000000..953ce61f8
--- /dev/null
+++ b/crypto/verifier/common_test.go
@@ -0,0 +1,101 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package verifier
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/pkg/errors"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+var (
+	MockHash = []byte{
+		0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+		0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+		0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+		0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+	}
+)
+
+type MockHeader struct{}
+
+func (*MockHeader) MarshalHash() ([]byte, error) {
+	return MockHash, nil
+}
+
+type MockObject struct {
+	MockHeader
+	HSV DefaultHashSignVerifierImpl
+}
+
+func (o *MockObject) Sign(signer *asymmetric.PrivateKey) error {
+	return o.HSV.Sign(&o.MockHeader, signer)
+}
+
+func (o *MockObject) Verify() error {
+	return o.HSV.Verify(&o.MockHeader)
+}
+
+func TestDefaultHashSignVerifierImpl(t *testing.T) {
+	Convey("Given a dummy object and a pair of keys", t, func() {
+		var (
+			obj          = &MockObject{}
+			priv, _, err = asymmetric.GenSecp256k1KeyPair()
+		)
+		So(err, ShouldBeNil)
+		So(priv, ShouldNotBeNil)
+		Convey("When the object is signed by the key pair", func() {
+			err = obj.Sign(priv)
+			So(err, ShouldBeNil)
+			Convey("The object should be verifiable", func() {
+				err = obj.Verify()
+				So(err, ShouldBeNil)
+			})
+			Convey("The object should have data hash", func() {
+				So(obj.HSV.Hash(), ShouldEqual, hash.THashH(MockHash))
+			})
+			Convey("When the hash is modified", func() {
+				obj.HSV.DataHash = hash.Hash{0x0, 0x0, 0x0, 0x1}
+				Convey("The verifier should return hash value not match error", func() {
+					err = errors.Cause(obj.Verify())
+					So(err, ShouldEqual, ErrHashValueNotMatch)
+				})
+			})
+			Convey("When the signee is modified", func() {
+				var _, pub, err = asymmetric.GenSecp256k1KeyPair()
+				So(err, ShouldBeNil)
+				obj.HSV.Signee = pub
+				Convey("The verifier should return signature not match error", func() {
+					err = errors.Cause(obj.Verify())
+					So(err, ShouldEqual, ErrSignatureNotMatch)
+				})
+			})
+			Convey("When the signature is modified", func() {
+				var val = obj.HSV.Signature.R
+				val.Add(val, big.NewInt(1))
+				Convey("The verifier should return signature not match error", func() {
+					err = errors.Cause(obj.Verify())
+					So(err, ShouldEqual, ErrSignatureNotMatch)
+				})
+			})
+		})
+	})
+}
diff --git a/proto/errors.go b/crypto/verifier/errors.go
similarity index 66%
rename from proto/errors.go
rename to crypto/verifier/errors.go
index cee9c752c..57da3f1f0 100644
--- a/proto/errors.go
+++ b/crypto/verifier/errors.go
@@ -14,14 +14,13 @@
  * limitations under the License.
  */
 
-package proto
+package verifier
 
-import "github.com/pkg/errors"
+import "errors"
 
 var (
-	// ErrHashVerification indicates a failed hash verification.
-	ErrHashVerification = errors.New("hash verification failed")
-
-	// ErrSignVerification indicates a failed signature verification.
-	ErrSignVerification = errors.New("signature verification failed")
+	// ErrHashValueNotMatch indicates the hash value not match error from verifier.
+	ErrHashValueNotMatch = errors.New("hash value not match")
+	// ErrSignatureNotMatch indicates the signature not match error from verifier.
+	ErrSignatureNotMatch = errors.New("signature not match")
 )
diff --git a/common/doc.go b/kayak/doc.go
similarity index 86%
rename from common/doc.go
rename to kayak/doc.go
index c42b8932e..ea76a4746 100644
--- a/common/doc.go
+++ b/kayak/doc.go
@@ -14,5 +14,5 @@
  * limitations under the License.
  */
 
-// Package common defines some common types which are used by multiple modules.
-package common
+// Package kayak implements a configurable consistency consensus middleware.
+package kayak
diff --git a/kayak/runtime.go b/kayak/runtime.go
index c160b1b16..8c763ceda 100644
--- a/kayak/runtime.go
+++ b/kayak/runtime.go
@@ -126,8 +126,18 @@ type commitResult struct {
 
 // NewRuntime creates new kayak Runtime.
 func NewRuntime(cfg *kt.RuntimeConfig) (rt *Runtime, err error) {
+	if cfg == nil {
+		err = errors.Wrap(kt.ErrInvalidConfig, "nil config")
+		return
+	}
+
 	peers := cfg.Peers
 
+	if peers == nil {
+		err = errors.Wrap(kt.ErrInvalidConfig, "nil peers")
+		return
+	}
+
 	// verify peers
 	if err = peers.Verify(); err != nil {
 		err = errors.Wrap(err, "verify peers during kayak init failed")
@@ -235,9 +245,6 @@ func (r *Runtime) Shutdown() (err error) {
 
 // Apply defines entry for Leader node.
 func (r *Runtime) Apply(ctx context.Context, req interface{}) (result interface{}, logIndex uint64, err error) {
-	r.peersLock.RLock()
-	defer r.peersLock.RUnlock()
-
 	var commitFuture <-chan *commitResult
 
 	var tmStart, tmLeaderPrepare, tmFollowerPrepare, tmCommitEnqueue, tmLeaderRollback,
@@ -280,9 +287,12 @@ func (r *Runtime) Apply(ctx context.Context, req interface{}) (result interface{
 		} else if !tmRollback.Before(tmStart) {
 			fields["t"] = tmRollback.Sub(tmStart).Nanoseconds()
 		}
-		log.WithFields(fields).Info("kayak leader apply")
+		log.WithFields(fields).WithError(err).Info("kayak leader apply")
 	}()
 
+	r.peersLock.RLock()
+	defer r.peersLock.RUnlock()
+
 	if r.role != proto.Leader {
 		// not leader
 		err = kt.ErrNotLeader
@@ -312,6 +322,10 @@ func (r *Runtime) Apply(ctx context.Context, req interface{}) (result interface{
 		return
 	}
 
+	// Leader pending map handling.
+	r.markPendingPrepare(prepareLog.Index)
+	defer r.markPrepareFinished(prepareLog.Index)
+
 	tmLeaderPrepare = time.Now()
 
 	// send prepare to all nodes
@@ -374,7 +388,8 @@ func (r *Runtime) Apply(ctx context.Context, req interface{}) (result interface{
 ROLLBACK:
 	// rollback local
 	var rollbackLog *kt.Log
-	if rollbackLog, err = r.leaderLogRollback(prepareLog.Index); err != nil {
+	var logErr error
+	if rollbackLog, logErr = r.leaderLogRollback(prepareLog.Index); logErr != nil {
 		// serve error, construct rollback log failed, internal error
 		// TODO(): CHANGE LEADER
 		return
@@ -397,6 +412,16 @@ func (r *Runtime) FollowerApply(l *kt.Log) (err error) {
 		return
 	}
 
+	var tmStart, tmEnd time.Time
+
+	defer func() {
+		log.WithFields(log.Fields{
+			"t": l.Type.String(),
+			"i": l.Index,
+			"c": tmEnd.Sub(tmStart).Nanoseconds(),
+		}).WithError(err).Info("kayak follower apply")
+	}()
+
 	r.peersLock.RLock()
 	defer r.peersLock.RUnlock()
 
@@ -497,6 +522,8 @@ func (r *Runtime) followerRollback(l *kt.Log) (err error) {
 		err = errors.Wrap(err, "write follower rollback log failed")
 	}
 
+	r.markPrepareFinished(l.Index)
+
 	return
 }
 
@@ -519,6 +546,8 @@ func (r *Runtime) followerCommit(l *kt.Log) (err error) {
 		err = cResult.err
 	}
 
+	r.markPrepareFinished(l.Index)
+
 	return
 }
 
@@ -659,10 +688,8 @@ func (r *Runtime) leaderDoCommit(req *commitReq) (dbCost time.Duration, tracker
 	result, err = r.sh.Commit(req.data)
 	dbCost = time.Now().Sub(tmStartDB)
 
-	if err == nil {
-		// mark last commit
-		atomic.StoreUint64(&r.lastCommit, l.Index)
-	}
+	// mark last commit
+	atomic.StoreUint64(&r.lastCommit, l.Index)
 
 	// send commit
 	tracker = r.rpc(l, r.minCommitFollowers)
@@ -699,9 +726,8 @@ func (r *Runtime) followerDoCommit(req *commitReq) (err error) {
 	// do commit, not wrapping underlying handler commit error
 	_, err = r.sh.Commit(req.data)
 
-	if err == nil {
-		atomic.StoreUint64(&r.lastCommit, req.log.Index)
-	}
+	// mark last commit
+	atomic.StoreUint64(&r.lastCommit, req.log.Index)
 
 	req.result <- &commitResult{err: err}
 
@@ -757,7 +783,7 @@ func (r *Runtime) readLogs() (err error) {
 	for {
 		if l, err = r.wal.Read(); err != nil && err != io.EOF {
 			err = errors.Wrap(err, "load previous logs in wal failed")
-			break
+			return
 		} else if err == io.EOF {
 			err = nil
 			break
@@ -773,16 +799,16 @@ func (r *Runtime) readLogs() (err error) {
 			var prepareLog *kt.Log
 			if lastCommit, prepareLog, err = r.getPrepareLog(l); err != nil {
 				err = errors.Wrap(err, "previous prepare does not exists, node need full recovery")
-				break
+				return
 			}
 			if lastCommit != r.lastCommit {
 				err = errors.Wrapf(err,
 					"last commit record in wal mismatched (expected: %v, actual: %v)", r.lastCommit, lastCommit)
-				break
+				return
 			}
 			if !r.pendingPrepares[prepareLog.Index] {
 				err = errors.Wrap(kt.ErrInvalidLog, "previous prepare already committed/rollback")
-				break
+				return
 			}
 			r.lastCommit = l.Index
 			// resolve previous prepared
@@ -790,18 +816,20 @@ func (r *Runtime) readLogs() (err error) {
 		case kt.LogRollback:
 			var prepareLog *kt.Log
 			if _, prepareLog, err = r.getPrepareLog(l); err != nil {
-				err = errors.Wrap(err, "previous prepare doe snot exists, node need full recovery")
+				err = errors.Wrap(err, "previous prepare does not exists, node need full recovery")
 				return
 			}
 			if !r.pendingPrepares[prepareLog.Index] {
 				err = errors.Wrap(kt.ErrInvalidLog, "previous prepare already committed/rollback")
-				break
+				return
 			}
 			// resolve previous prepared
 			delete(r.pendingPrepares, prepareLog.Index)
+		case kt.LogBarrier:
+		case kt.LogNoop:
 		default:
 			err = errors.Wrapf(kt.ErrInvalidLog, "invalid log type: %v", l.Type)
-			break
+			return
 		}
 
 		// record nextIndex
@@ -842,11 +870,11 @@ func (r *Runtime) markPrepareFinished(index uint64) {
 }
 
 func (r *Runtime) errorSummary(errs map[proto.NodeID]error) error {
-	failNodes := make([]proto.NodeID, 0, len(errs))
+	failNodes := make(map[proto.NodeID]error)
 
 	for s, err := range errs {
 		if err != nil {
-			failNodes = append(failNodes, s)
+			failNodes[s] = err
 		}
 	}
 
@@ -880,16 +908,6 @@ func (r *Runtime) getCaller(id proto.NodeID) Caller {
 	return rawCaller.(Caller)
 }
 
-// SetCaller injects caller for test purpose.
-func (r *Runtime) SetCaller(id proto.NodeID, c Caller) {
-	r.callerMap.Store(id, c)
-}
-
-// RemoveCaller removes cached caller.
-func (r *Runtime) RemoveCaller(id proto.NodeID) {
-	r.callerMap.Delete(id)
-}
-
 func (r *Runtime) goFunc(f func()) {
 	r.wg.Add(1)
 	go func() {
diff --git a/kayak/runtime_inject_test.go b/kayak/runtime_inject_test.go
new file mode 100644
index 000000000..1f729770e
--- /dev/null
+++ b/kayak/runtime_inject_test.go
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kayak
+
+import "github.com/CovenantSQL/CovenantSQL/proto"
+
+// SetCaller injects caller for test purpose.
+func (r *Runtime) SetCaller(id proto.NodeID, c Caller) {
+	r.callerMap.Store(id, c)
+}
diff --git a/kayak/test/runtime_test.go b/kayak/runtime_test.go
similarity index 50%
rename from kayak/test/runtime_test.go
rename to kayak/runtime_test.go
index 5d86b43ee..101883bab 100644
--- a/kayak/test/runtime_test.go
+++ b/kayak/runtime_test.go
@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-package test
+package kayak_test
 
 import (
 	"bytes"
 	"context"
 	"database/sql"
+	"encoding/binary"
 	"fmt"
 	"math/rand"
 	"net"
@@ -34,7 +35,7 @@ import (
 	kt "github.com/CovenantSQL/CovenantSQL/kayak/types"
 	kl "github.com/CovenantSQL/CovenantSQL/kayak/wal"
 	"github.com/CovenantSQL/CovenantSQL/proto"
-	"github.com/CovenantSQL/CovenantSQL/sqlchain/storage"
+	"github.com/CovenantSQL/CovenantSQL/storage"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
 	"github.com/jordwest/mock-conn"
@@ -190,7 +191,313 @@ func (c *fakeCaller) Call(method string, req interface{}, resp interface{}) (err
 	return client.Call(method, req, resp)
 }
 
-func BenchmarkNewRuntime(b *testing.B) {
+func TestRuntime(t *testing.T) {
+	Convey("runtime test", t, func(c C) {
+		lvl := log.GetLevel()
+		log.SetLevel(log.FatalLevel)
+		defer log.SetLevel(lvl)
+		db1, err := newSQLiteStorage("test1.db")
+		So(err, ShouldBeNil)
+		defer func() {
+			db1.Close()
+			os.Remove("test1.db")
+		}()
+		db2, err := newSQLiteStorage("test2.db")
+		So(err, ShouldBeNil)
+		defer func() {
+			db2.Close()
+			os.Remove("test2.db")
+		}()
+
+		node1 := proto.NodeID("000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade")
+		node2 := proto.NodeID("000005f4f22c06f76c43c4f48d5a7ec1309cc94030cbf9ebae814172884ac8b5")
+
+		peers := &proto.Peers{
+			PeersHeader: proto.PeersHeader{
+				Leader: node1,
+				Servers: []proto.NodeID{
+					node1,
+					node2,
+				},
+			},
+		}
+
+		privKey, _, err := asymmetric.GenSecp256k1KeyPair()
+		So(err, ShouldBeNil)
+		err = peers.Sign(privKey)
+		So(err, ShouldBeNil)
+
+		wal1 := kl.NewMemWal()
+		defer wal1.Close()
+		cfg1 := &kt.RuntimeConfig{
+			Handler:          db1,
+			PrepareThreshold: 1.0,
+			CommitThreshold:  1.0,
+			PrepareTimeout:   time.Second,
+			CommitTimeout:    10 * time.Second,
+			Peers:            peers,
+			Wal:              wal1,
+			NodeID:           node1,
+			ServiceName:      "Test",
+			MethodName:       "Call",
+		}
+		rt1, err := kayak.NewRuntime(cfg1)
+		So(err, ShouldBeNil)
+
+		wal2 := kl.NewMemWal()
+		defer wal2.Close()
+		cfg2 := &kt.RuntimeConfig{
+			Handler:          db2,
+			PrepareThreshold: 1.0,
+			CommitThreshold:  1.0,
+			PrepareTimeout:   time.Second,
+			CommitTimeout:    10 * time.Second,
+			Peers:            peers,
+			Wal:              wal2,
+			NodeID:           node2,
+			ServiceName:      "Test",
+			MethodName:       "Call",
+		}
+		rt2, err := kayak.NewRuntime(cfg2)
+		So(err, ShouldBeNil)
+
+		m := newFakeMux()
+		fs1 := newFakeService(rt1)
+		m.register(node1, fs1)
+		fs2 := newFakeService(rt2)
+		m.register(node2, fs2)
+
+		rt1.SetCaller(node2, newFakeCaller(m, node2))
+		rt2.SetCaller(node1, newFakeCaller(m, node1))
+
+		err = rt1.Start()
+		So(err, ShouldBeNil)
+		defer rt1.Shutdown()
+
+		err = rt2.Start()
+		So(err, ShouldBeNil)
+		defer rt2.Shutdown()
+
+		q1 := &queryStructure{
+			Queries: []storage.Query{
+				{Pattern: "CREATE TABLE IF NOT EXISTS test (t1 text, t2 text, t3 text)"},
+			},
+		}
+		So(err, ShouldBeNil)
+
+		r1 := RandStringRunes(333)
+		r2 := RandStringRunes(333)
+		r3 := RandStringRunes(333)
+
+		q2 := &queryStructure{
+			Queries: []storage.Query{
+				{
+					Pattern: "INSERT INTO test (t1, t2, t3) VALUES(?, ?, ?)",
+					Args: []sql.NamedArg{
+						sql.Named("", r1),
+						sql.Named("", r2),
+						sql.Named("", r3),
+					},
+				},
+			},
+		}
+
+		rt1.Apply(context.Background(), q1)
+		rt2.Apply(context.Background(), q2)
+		rt1.Apply(context.Background(), q2)
+		db1.Query(context.Background(), []storage.Query{
+			{Pattern: "SELECT * FROM test"},
+		})
+
+		var count uint64
+		atomic.StoreUint64(&count, 1)
+
+		for i := 0; i != 1000; i++ {
+			atomic.AddUint64(&count, 1)
+			q := &queryStructure{
+				Queries: []storage.Query{
+					{
+						Pattern: "INSERT INTO test (t1, t2, t3) VALUES(?, ?, ?)",
+						Args: []sql.NamedArg{
+							sql.Named("", r1),
+							sql.Named("", r2),
+							sql.Named("", r3),
+						},
+					},
+				},
+			}
+
+			_, _, err = rt1.Apply(context.Background(), q)
+			So(err, ShouldBeNil)
+		}
+
+		// test rollback
+		q := &queryStructure{
+			Queries: []storage.Query{
+				{
+					Pattern: "INVALID QUERY",
+				},
+			},
+		}
+		_, _, err = rt1.Apply(context.Background(), q)
+		So(err, ShouldNotBeNil)
+
+		// test timeout
+		q = &queryStructure{
+			Queries: []storage.Query{
+				{
+					Pattern: "INSERT INTO test (t1, t2, t3) VALUES(?, ?, ?)",
+					Args: []sql.NamedArg{
+						sql.Named("", r1),
+						sql.Named("", r2),
+						sql.Named("", r3),
+					},
+				},
+			},
+		}
+		cancelCtx, cancelCtxFunc := context.WithCancel(context.Background())
+		cancelCtxFunc()
+		_, _, err = rt1.Apply(cancelCtx, q)
+		So(err, ShouldNotBeNil)
+
+		total := atomic.LoadUint64(&count)
+		_, _, d1, _ := db1.Query(context.Background(), []storage.Query{
+			{Pattern: "SELECT COUNT(1) FROM test"},
+		})
+		So(d1, ShouldHaveLength, 1)
+		So(d1[0], ShouldHaveLength, 1)
+		So(fmt.Sprint(d1[0][0]), ShouldEqual, fmt.Sprint(total))
+
+		_, _, d2, _ := db2.Query(context.Background(), []storage.Query{
+			{Pattern: "SELECT COUNT(1) FROM test"},
+		})
+		So(d2, ShouldHaveLength, 1)
+		So(d2[0], ShouldHaveLength, 1)
+		So(fmt.Sprint(d2[0][0]), ShouldResemble, fmt.Sprint(total))
+	})
+	Convey("trivial cases", t, func() {
+		node1 := proto.NodeID("000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade")
+		node2 := proto.NodeID("000005f4f22c06f76c43c4f48d5a7ec1309cc94030cbf9ebae814172884ac8b5")
+		node3 := proto.NodeID("000003f49592f83d0473bddb70d543f1096b4ffed5e5f942a3117e256b7052b8")
+
+		peers := &proto.Peers{
+			PeersHeader: proto.PeersHeader{
+				Leader: node1,
+				Servers: []proto.NodeID{
+					node1,
+					node2,
+				},
+			},
+		}
+
+		_, err := kayak.NewRuntime(nil)
+		So(err, ShouldNotBeNil)
+		_, err = kayak.NewRuntime(&kt.RuntimeConfig{})
+		So(err, ShouldNotBeNil)
+		_, err = kayak.NewRuntime(&kt.RuntimeConfig{
+			Peers: peers,
+		})
+		So(err, ShouldNotBeNil)
+
+		privKey, _, err := asymmetric.GenSecp256k1KeyPair()
+		So(err, ShouldBeNil)
+		err = peers.Sign(privKey)
+		So(err, ShouldBeNil)
+
+		_, err = kayak.NewRuntime(&kt.RuntimeConfig{
+			Peers:  peers,
+			NodeID: node3,
+		})
+		So(err, ShouldNotBeNil)
+	})
+	Convey("test log loading", t, func() {
+		w, err := kl.NewLevelDBWal("testLoad.db")
+		defer os.RemoveAll("testLoad.db")
+		So(err, ShouldBeNil)
+		err = w.Write(&kt.Log{
+			LogHeader: kt.LogHeader{
+				Index:    0,
+				Type:     kt.LogPrepare,
+				Producer: proto.NodeID("0000000000000000000000000000000000000000000000000000000000000000"),
+			},
+			Data: []byte("happy1"),
+		})
+		So(err, ShouldBeNil)
+		err = w.Write(&kt.Log{
+			LogHeader: kt.LogHeader{
+				Index:    1,
+				Type:     kt.LogPrepare,
+				Producer: proto.NodeID("0000000000000000000000000000000000000000000000000000000000000000"),
+			},
+			Data: []byte("happy1"),
+		})
+		So(err, ShouldBeNil)
+		data := make([]byte, 16)
+		binary.BigEndian.PutUint64(data, 0) // prepare log index
+		binary.BigEndian.PutUint64(data, 0) // last commit index
+		err = w.Write(&kt.Log{
+			LogHeader: kt.LogHeader{
+				Index:    2,
+				Type:     kt.LogCommit,
+				Producer: proto.NodeID("0000000000000000000000000000000000000000000000000000000000000000"),
+			},
+			Data: data,
+		})
+		So(err, ShouldBeNil)
+		data = make([]byte, 8)
+		binary.BigEndian.PutUint64(data, 1) // prepare log index
+		err = w.Write(&kt.Log{
+			LogHeader: kt.LogHeader{
+				Index:    3,
+				Type:     kt.LogRollback,
+				Producer: proto.NodeID("0000000000000000000000000000000000000000000000000000000000000000"),
+			},
+			Data: data,
+		})
+		So(err, ShouldBeNil)
+		w.Close()
+
+		w, err = kl.NewLevelDBWal("testLoad.db")
+		So(err, ShouldBeNil)
+		defer w.Close()
+
+		node1 := proto.NodeID("000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade")
+		peers := &proto.Peers{
+			PeersHeader: proto.PeersHeader{
+				Leader:  node1,
+				Servers: []proto.NodeID{node1},
+			},
+		}
+
+		privKey, _, err := asymmetric.GenSecp256k1KeyPair()
+		So(err, ShouldBeNil)
+		err = peers.Sign(privKey)
+		So(err, ShouldBeNil)
+
+		cfg := &kt.RuntimeConfig{
+			Handler:          nil,
+			PrepareThreshold: 1.0,
+			CommitThreshold:  1.0,
+			PrepareTimeout:   time.Second,
+			CommitTimeout:    10 * time.Second,
+			Peers:            peers,
+			Wal:              w,
+			NodeID:           node1,
+			ServiceName:      "Test",
+			MethodName:       "Call",
+		}
+		rt, err := kayak.NewRuntime(cfg)
+		So(err, ShouldBeNil)
+
+		So(rt.Start(), ShouldBeNil)
+		So(func() { rt.Start() }, ShouldNotPanic)
+
+		So(rt.Shutdown(), ShouldBeNil)
+		So(func() { rt.Shutdown() }, ShouldNotPanic)
+	})
+}
+
+func BenchmarkRuntime(b *testing.B) {
 	Convey("runtime test", b, func(c C) {
 		log.SetLevel(log.DebugLevel)
 		f, err := os.OpenFile("test.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600)
@@ -230,6 +537,7 @@ func BenchmarkNewRuntime(b *testing.B) {
 		So(err, ShouldBeNil)
 
 		wal1 := kl.NewMemWal()
+		defer wal1.Close()
 		cfg1 := &kt.RuntimeConfig{
 			Handler:          db1,
 			PrepareThreshold: 1.0,
@@ -246,6 +554,7 @@ func BenchmarkNewRuntime(b *testing.B) {
 		So(err, ShouldBeNil)
 
 		wal2 := kl.NewMemWal()
+		defer wal2.Close()
 		cfg2 := &kt.RuntimeConfig{
 			Handler:          db2,
 			PrepareThreshold: 1.0,
diff --git a/kayak/tracker.go b/kayak/tracker.go
index 7eef7ed6a..986a9198b 100644
--- a/kayak/tracker.go
+++ b/kayak/tracker.go
@@ -90,6 +90,7 @@ func (t *rpcTracker) send() {
 
 func (t *rpcTracker) callSingle(idx int) {
 	err := t.r.getCaller(t.nodes[idx]).Call(t.method, t.req, nil)
+	defer t.wg.Done()
 	t.errLock.Lock()
 	defer t.errLock.Unlock()
 	t.errors[t.nodes[idx]] = err
diff --git a/kayak/tracker_test.go b/kayak/tracker_test.go
new file mode 100644
index 000000000..6ffccce6b
--- /dev/null
+++ b/kayak/tracker_test.go
@@ -0,0 +1,103 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kayak
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/pkg/errors"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+type fakeTrackerCaller struct {
+	c C
+}
+
+func (c *fakeTrackerCaller) Call(method string, req interface{}, resp interface{}) (err error) {
+	time.Sleep(time.Millisecond * 500)
+	c.c.So(method, ShouldEqual, "test")
+	if req != 1 {
+		err = errors.New("invalid result")
+	}
+	return
+}
+
+func TestTracker(t *testing.T) {
+	Convey("test tracker", t, func(c C) {
+		nodeID1 := proto.NodeID("000005f4f22c06f76c43c4f48d5a7ec1309cc94030cbf9ebae814172884ac8b5")
+		nodeID2 := proto.NodeID("000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade")
+		r := &Runtime{
+			rpcMethod: "test",
+			followers: []proto.NodeID{
+				nodeID1,
+				nodeID2,
+			},
+		}
+		r.SetCaller(nodeID1, &fakeTrackerCaller{c: c})
+		r.SetCaller(nodeID2, &fakeTrackerCaller{c: c})
+		t1 := newTracker(r, 1, 0)
+		t1.send()
+		_, meets, _ := t1.get(context.Background())
+		So(meets, ShouldBeTrue)
+
+		t2 := newTracker(r, 1, 1)
+		t2.send()
+		r2, meets, _ := t2.get(context.Background())
+		So(r2, ShouldNotBeEmpty)
+		So(meets, ShouldBeTrue)
+
+		t3 := newTracker(r, 1, 1)
+		t3.send()
+		ctx1, cancelCtx1 := context.WithTimeout(context.Background(), time.Millisecond*1)
+		defer cancelCtx1()
+		r3, meets, finished := t3.get(ctx1)
+		So(r3, ShouldBeEmpty)
+		So(meets, ShouldBeFalse)
+		So(finished, ShouldBeFalse)
+
+		r3, meets, finished = t3.get(context.Background())
+		So(r3, ShouldNotBeEmpty)
+		So(meets, ShouldBeTrue)
+
+		t4 := newTracker(r, 1, 2)
+		t4.send()
+		r4, meets, finished := t4.get(context.Background())
+		So(r4, ShouldHaveLength, 2)
+		So(meets, ShouldBeTrue)
+		So(finished, ShouldBeTrue)
+
+		t5 := newTracker(r, 2, 2)
+		t5.send()
+		ctx2, cancelCtx2 := context.WithTimeout(context.Background(), time.Millisecond*1)
+		defer cancelCtx2()
+		r5, meets, finished := t5.get(ctx2)
+		So(r5, ShouldBeEmpty)
+		So(meets, ShouldBeFalse)
+		So(finished, ShouldBeFalse)
+
+		r5, meets, finished = t5.get(context.Background())
+		So(r5, ShouldHaveLength, 2)
+		So(meets, ShouldBeTrue)
+		So(finished, ShouldBeTrue)
+
+		t5.close()
+		So(t5.closed, ShouldEqual, 1)
+	})
+}
diff --git a/kayak/types/doc.go b/kayak/types/doc.go
index 28c02e239..ffdd029c8 100644
--- a/kayak/types/doc.go
+++ b/kayak/types/doc.go
@@ -14,4 +14,5 @@
  * limitations under the License.
  */
 
+// Package types defines required types of kayak.
 package types
diff --git a/kayak/types/errors.go b/kayak/types/errors.go
index baa5b824b..6ceab9c9d 100644
--- a/kayak/types/errors.go
+++ b/kayak/types/errors.go
@@ -33,4 +33,6 @@ var (
 	ErrNotInPeer = errors.New("node not in peer")
 	// ErrNeedRecovery represents current follower node needs recovery, back-off is required by leader.
 	ErrNeedRecovery = errors.New("need recovery")
+	// ErrInvalidConfig represents invalid kayak runtime config.
+	ErrInvalidConfig = errors.New("invalid runtime config")
 )
diff --git a/kayak/types/log.go b/kayak/types/log.go
index a69ce2ef5..38238f72f 100644
--- a/kayak/types/log.go
+++ b/kayak/types/log.go
@@ -30,6 +30,8 @@ const (
 	LogRollback
 	// LogCommit defines the commit phase of a commit.
 	LogCommit
+	// LogCheckpoint defines the checkpoint log (created/virtually created by block production or log truncation).
+	LogCheckpoint
 	// LogBarrier defines barrier log, all open windows should be waiting this operations to complete.
 	LogBarrier
 	// LogNoop defines noop log.
@@ -44,12 +46,14 @@ func (t LogType) String() (s string) {
 		return "LogRollback"
 	case LogCommit:
 		return "LogCommit"
+	case LogCheckpoint:
+		return "LogCheckpoint"
 	case LogBarrier:
 		return "LogBarrier"
 	case LogNoop:
 		return "LogNoop"
 	default:
-		return
+		return "Unknown"
 	}
 }
 
diff --git a/kayak/types/log_test.go b/kayak/types/log_test.go
new file mode 100644
index 000000000..c737e9b91
--- /dev/null
+++ b/kayak/types/log_test.go
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"testing"
+
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestLogType_String(t *testing.T) {
+	Convey("test log string function", t, func() {
+		for i := LogPrepare; i <= LogNoop+1; i++ {
+			So(i.String(), ShouldNotBeEmpty)
+		}
+	})
+}
diff --git a/kayak/wal/doc.go b/kayak/wal/doc.go
index 953b5f875..31e6ee6b4 100644
--- a/kayak/wal/doc.go
+++ b/kayak/wal/doc.go
@@ -14,4 +14,5 @@
  * limitations under the License.
  */
 
+// Package wal defines toy implementations of kayak wal.
 package wal
diff --git a/kayak/wal/leveldb_wal.go b/kayak/wal/leveldb_wal.go
index 813b8c02d..8382744de 100644
--- a/kayak/wal/leveldb_wal.go
+++ b/kayak/wal/leveldb_wal.go
@@ -20,7 +20,6 @@ import (
 	"bytes"
 	"encoding/binary"
 	"io"
-	"sort"
 	"sync"
 	"sync/atomic"
 
@@ -37,20 +36,15 @@ var (
 	logHeaderKeyPrefix = []byte{'L', 'H'}
 	// logDataKeyPrefix defines the leveldb data key prefix.
 	logDataKeyPrefix = []byte{'L', 'D'}
-	// baseIndexKey defines the base index key.
-	baseIndexKey = []byte{'B', 'I'}
 )
 
 // LevelDBWal defines a toy wal using leveldb as storage.
 type LevelDBWal struct {
-	db          *leveldb.DB
-	it          iterator.Iterator
-	base        uint64
-	closed      uint32
-	readLock    sync.Mutex
-	read        uint32
-	pending     []uint64
-	pendingLock sync.Mutex
+	db       *leveldb.DB
+	it       iterator.Iterator
+	closed   uint32
+	readLock sync.Mutex
+	read     uint32
 }
 
 // NewLevelDBWal returns new leveldb wal instance.
@@ -61,15 +55,6 @@ func NewLevelDBWal(filename string) (p *LevelDBWal, err error) {
 		return
 	}
 
-	// load current base
-	var baseValue []byte
-	if baseValue, err = p.db.Get(baseIndexKey, nil); err == nil {
-		// decode base
-		p.base = p.bytesToUint64(baseValue)
-	} else {
-		err = nil
-	}
-
 	return
 }
 
@@ -80,17 +65,14 @@ func (p *LevelDBWal) Write(l *kt.Log) (err error) {
 		return
 	}
 
+	// mark wal as already read
+	atomic.CompareAndSwapUint32(&p.read, 0, 1)
+
 	if l == nil {
 		err = ErrInvalidLog
 		return
 	}
 
-	if l.Index < p.base {
-		// already exists
-		err = ErrAlreadyExists
-		return
-	}
-
 	// build header headerKey
 	headerKey := append(append([]byte(nil), logHeaderKeyPrefix...), p.uint64ToBytes(l.Index)...)
 
@@ -130,13 +112,16 @@ func (p *LevelDBWal) Write(l *kt.Log) (err error) {
 		return
 	}
 
-	p.updatePending(l.Index)
-
 	return
 }
 
 // Read implements Wal.Read.
 func (p *LevelDBWal) Read() (l *kt.Log, err error) {
+	if atomic.LoadUint32(&p.closed) == 1 {
+		err = ErrWalClosed
+		return
+	}
+
 	if atomic.LoadUint32(&p.read) == 1 {
 		err = io.EOF
 		return
@@ -154,10 +139,6 @@ func (p *LevelDBWal) Read() (l *kt.Log, err error) {
 	if p.it.Next() {
 		// load
 		l, err = p.load(p.it.Value())
-		// update base and pending
-		if err == nil {
-			p.updatePending(l.Index)
-		}
 		return
 	}
 
@@ -209,32 +190,15 @@ func (p *LevelDBWal) Close() {
 	}
 }
 
-func (p *LevelDBWal) updatePending(index uint64) {
-	p.pendingLock.Lock()
-	defer p.pendingLock.Unlock()
-
-	if atomic.CompareAndSwapUint64(&p.base, index, index+1) {
-		// process pending
-		for len(p.pending) > 0 {
-			if !atomic.CompareAndSwapUint64(&p.base, p.pending[0], p.pending[0]+1) {
-				break
-			}
-			p.pending = p.pending[1:]
-		}
-
-		// commit base index to database
-		_ = p.db.Put(baseIndexKey, p.uint64ToBytes(atomic.LoadUint64(&p.base)), nil)
-	} else {
-		i := sort.Search(len(p.pending), func(i int) bool {
-			return p.pending[i] >= index
-		})
-
-		if len(p.pending) == i || p.pending[i] != index {
-			p.pending = append(p.pending, 0)
-			copy(p.pending[i+1:], p.pending[i:])
-			p.pending[i] = index
-		}
+// GetDB returns the leveldb for storage extensions.
+func (p *LevelDBWal) GetDB() (d *leveldb.DB, err error) {
+	if atomic.LoadUint32(&p.closed) == 1 {
+		err = ErrWalClosed
+		return
 	}
+
+	d = p.db
+	return
 }
 
 func (p *LevelDBWal) load(logHeader []byte) (l *kt.Log, err error) {
@@ -266,7 +230,3 @@ func (p *LevelDBWal) uint64ToBytes(o uint64) (res []byte) {
 	binary.BigEndian.PutUint64(res, o)
 	return
 }
-
-func (p *LevelDBWal) bytesToUint64(b []byte) uint64 {
-	return binary.BigEndian.Uint64(b)
-}
diff --git a/kayak/wal/leveldb_wal_test.go b/kayak/wal/leveldb_wal_test.go
index db21e5aca..25b005be5 100644
--- a/kayak/wal/leveldb_wal_test.go
+++ b/kayak/wal/leveldb_wal_test.go
@@ -17,6 +17,7 @@
 package wal
 
 import (
+	"io"
 	"os"
 	"testing"
 
@@ -26,15 +27,17 @@ import (
 )
 
 func TestLevelDBWal_Write(t *testing.T) {
-	Convey("test leveldb wal write", t, func() {
+	Convey("wal write/get/close", t, func() {
+		dbFile := "testWrite.ldb"
+
 		var p *LevelDBWal
 		var err error
-		p, err = NewLevelDBWal("testWrite.ldb")
+		p, err = NewLevelDBWal(dbFile)
 		So(err, ShouldBeNil)
-		defer func() {
-			p.Close()
-			os.RemoveAll("testWrite.ldb")
-		}()
+		defer os.RemoveAll(dbFile)
+
+		err = p.Write(nil)
+		So(err, ShouldNotBeNil)
 
 		l1 := &kt.Log{
 			LogHeader: kt.LogHeader{
@@ -56,6 +59,9 @@ func TestLevelDBWal_Write(t *testing.T) {
 		So(err, ShouldBeNil)
 		So(l, ShouldResemble, l1)
 
+		_, err = p.Get(10000)
+		So(err, ShouldNotBeNil)
+
 		// test consecutive writes
 		l2 := &kt.Log{
 			LogHeader: kt.LogHeader{
@@ -87,5 +93,54 @@ func TestLevelDBWal_Write(t *testing.T) {
 		}
 		err = p.Write(l3)
 		So(err, ShouldBeNil)
+
+		_, err = p.Read()
+		So(err, ShouldEqual, io.EOF)
+
+		p.Close()
+
+		_, err = p.Read()
+		So(err, ShouldEqual, ErrWalClosed)
+
+		err = p.Write(l1)
+		So(err, ShouldEqual, ErrWalClosed)
+
+		_, err = p.Get(l1.Index)
+		So(err, ShouldEqual, ErrWalClosed)
+
+		// load again
+		p, err = NewLevelDBWal(dbFile)
+		So(err, ShouldBeNil)
+
+		for i := 0; i != 4; i++ {
+			l, err = p.Read()
+			So(err, ShouldBeNil)
+			So(l.Index, ShouldEqual, i)
+		}
+
+		_, err = p.Read()
+		So(err, ShouldEqual, io.EOF)
+
+		p.Close()
+
+		// load again
+		p, err = NewLevelDBWal(dbFile)
+		So(err, ShouldBeNil)
+
+		// not complete read
+		for i := 0; i != 3; i++ {
+			l, err = p.Read()
+			So(err, ShouldBeNil)
+			So(l.Index, ShouldEqual, i)
+		}
+
+		p.Close()
+
+		// close multiple times
+		So(p.Close, ShouldNotPanic)
+	})
+	Convey("open failed test", t, func() {
+		_, err := NewLevelDBWal("")
+		So(err, ShouldNotBeNil)
 	})
 }
diff --git a/kayak/wal/mem_wal.go b/kayak/wal/mem_wal.go
index 0b2e7d2ed..a1e63d6aa 100644
--- a/kayak/wal/mem_wal.go
+++ b/kayak/wal/mem_wal.go
@@ -79,23 +79,7 @@ func (p *MemWal) Read() (l *kt.Log, err error) {
 		return
 	}
 
-	p.RLock()
-	defer p.RUnlock()
-
-	if atomic.LoadUint64(&p.offset) >= uint64(len(p.logs)) {
-		err = io.EOF
-		return
-	}
-
-	index := atomic.AddUint64(&p.offset, 1) - 1
-	if index >= uint64(len(p.logs)) {
-		// error
-		err = io.EOF
-		return
-	}
-
-	l = p.logs[index]
-
+	err = io.EOF
 	return
 }
 
diff --git a/kayak/wal/mem_wal_test.go b/kayak/wal/mem_wal_test.go
index 1a539ccb0..c79db6959 100644
--- a/kayak/wal/mem_wal_test.go
+++ b/kayak/wal/mem_wal_test.go
@@ -17,6 +17,7 @@
 package wal
 
 import (
+	"io"
 	"sync"
 	"testing"
 
@@ -53,6 +54,9 @@ func TestMemWal_Write(t *testing.T) {
 		So(err, ShouldBeNil)
 		So(l, ShouldResemble, l1)
 
+		_, err = p.Get(10000)
+		So(err, ShouldNotBeNil)
+
 		// test consecutive writes
 		l2 := &kt.Log{
 			LogHeader: kt.LogHeader{
@@ -93,6 +97,19 @@ func TestMemWal_Write(t *testing.T) {
 		So(p.revIndex, ShouldHaveLength, 4)
 		So(p.revIndex[l3.Index], ShouldEqual, 3)
 		So(p.offset, ShouldEqual, 4)
+
+		_, err = p.Read()
+		So(err, ShouldEqual, io.EOF)
+
+		p.Close()
+		_, err = p.Read()
+		So(err, ShouldEqual, ErrWalClosed)
+
+		_, err = p.Get(1)
+		So(err, ShouldEqual, ErrWalClosed)
+
+		err = p.Write(l1)
+		So(err, ShouldEqual, ErrWalClosed)
 	})
 }
 
diff --git a/metric/rpc.go b/metric/rpc.go
index 232854826..57ee7eb2e 100644
--- a/metric/rpc.go
+++ b/metric/rpc.go
@@ -147,6 +147,6 @@ func (cc *CollectClient) UploadMetrics(BPNodeID proto.NodeID) (err error) {
 	if err != nil {
 		log.Errorf("calling RPC %s failed: %s", reqType, err)
 	}
-	log.Infof("resp %s: %v", reqType, resp)
+	log.Debugf("resp %s: %v", reqType, resp)
 	return
 }
diff --git a/proto/servers.go b/proto/servers.go
index 27d935fee..fc61c2cd4 100644
--- a/proto/servers.go
+++ b/proto/servers.go
@@ -18,7 +18,7 @@ package proto
 
 import (
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
-	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
 )
 
 //go:generate hsp
@@ -34,57 +34,27 @@ type PeersHeader struct {
 // Peers defines the peers configuration.
 type Peers struct {
 	PeersHeader
-	Hash      hash.Hash
-	Signee    *asymmetric.PublicKey
-	Signature *asymmetric.Signature
+	verifier.DefaultHashSignVerifierImpl
 }
 
 // Clone makes a deep copy of Peers.
 func (p *Peers) Clone() (copy Peers) {
 	copy.Version = p.Version
+	copy.Term = p.Term
 	copy.Leader = p.Leader
 	copy.Servers = append(copy.Servers, p.Servers...)
-	copy.Signee = p.Signee
-	copy.Signature = p.Signature
+	copy.DefaultHashSignVerifierImpl = p.DefaultHashSignVerifierImpl
 	return
 }
 
 // Sign generates signature.
 func (p *Peers) Sign(signer *asymmetric.PrivateKey) (err error) {
-	var enc []byte
-	if enc, err = p.PeersHeader.MarshalHash(); err != nil {
-		return
-	}
-
-	var h = hash.THashH(enc)
-	if p.Signature, err = signer.Sign(h[:]); err != nil {
-		return
-	}
-
-	p.Hash = h
-	p.Signee = signer.PubKey()
-	return
+	return p.DefaultHashSignVerifierImpl.Sign(&p.PeersHeader, signer)
 }
 
 // Verify verify signature.
 func (p *Peers) Verify() (err error) {
-	var enc []byte
-	if enc, err = p.PeersHeader.MarshalHash(); err != nil {
-		return
-	}
-
-	var h = hash.THashH(enc)
-	if !p.Hash.IsEqual(&h) {
-		err = ErrHashVerification
-		return
-	}
-
-	if !p.Signature.Verify(h[:], p.Signee) {
-		err = ErrSignVerification
-		return
-	}
-
-	return
+	return p.DefaultHashSignVerifierImpl.Verify(&p.PeersHeader)
 }
 
 // Find finds the index of the server with the specified key in the server list.
diff --git a/proto/servers_gen.go b/proto/servers_gen.go
index 7357a4dfd..8041564e7 100644
--- a/proto/servers_gen.go
+++ b/proto/servers_gen.go
@@ -10,35 +10,15 @@ import (
 func (z *Peers) MarshalHash() (o []byte, err error) {
 	var b []byte
 	o = hsp.Require(b, z.Msgsize())
-	// map header, size 4
-	o = append(o, 0x84, 0x84)
-	if z.Signee == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signee.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
-	o = append(o, 0x84)
-	if z.Signature == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signature.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
-	o = append(o, 0x84)
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
 	if oTemp, err := z.PeersHeader.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
 	}
-	o = append(o, 0x84)
-	if oTemp, err := z.Hash.MarshalHash(); err != nil {
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -48,19 +28,7 @@ func (z *Peers) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *Peers) Msgsize() (s int) {
-	s = 1 + 7
-	if z.Signee == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signee.Msgsize()
-	}
-	s += 10
-	if z.Signature == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signature.Msgsize()
-	}
-	s += 12 + z.PeersHeader.Msgsize() + 5 + z.Hash.Msgsize()
+	s = 1 + 12 + z.PeersHeader.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
 	return
 }
 
diff --git a/proto/servers_test.go b/proto/servers_test.go
new file mode 100644
index 000000000..1260b6227
--- /dev/null
+++ b/proto/servers_test.go
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package proto
+
+import (
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/utils"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestPeers(t *testing.T) {
+	Convey("test peers", t, func() {
+		privKey, _, err := asymmetric.GenSecp256k1KeyPair()
+		So(err, ShouldBeNil)
+		p := &Peers{
+			PeersHeader: PeersHeader{
+				Term:   1,
+				Leader: NodeID("00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9"),
+				Servers: []NodeID{
+					NodeID("00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9"),
+					NodeID("00000381d46fd6cf7742d7fb94e2422033af989c0e348b5781b3219599a3af35"),
+				},
+			},
+		}
+		err = p.Sign(privKey)
+		So(err, ShouldBeNil)
+		err = p.Verify()
+		So(err, ShouldBeNil)
+
+		// after encode/decode
+		buf, err := utils.EncodeMsgPack(p)
+		var peers *Peers
+		err = utils.DecodeMsgPack(buf.Bytes(), &peers)
+		So(err, ShouldBeNil)
+		err = peers.Verify()
+		So(err, ShouldBeNil)
+
+		peers2 := peers.Clone()
+		err = peers2.Verify()
+		So(err, ShouldBeNil)
+
+		i, found := peers.Find(NodeID("00000381d46fd6cf7742d7fb94e2422033af989c0e348b5781b3219599a3af35"))
+		So(i, ShouldEqual, 1)
+		So(found, ShouldBeTrue)
+
+		i, found = peers.Find(NodeID("0000000000000000000000000000000000000000000000000000000000000001"))
+		So(found, ShouldBeFalse)
+
+		// verify hash failed
+		peers.Term = 2
+		err = peers.Verify()
+		So(err, ShouldNotBeNil)
+		err = peers.Sign(privKey)
+		So(err, ShouldBeNil)
+
+		// verify failed
+		p.Signature = peers.Signature
+		err = p.Verify()
+		So(err, ShouldNotBeNil)
+	})
+}
diff --git a/route/acl.go b/route/acl.go
index 25fdf7494..9664f7e3c 100644
--- a/route/acl.go
+++ b/route/acl.go
@@ -77,8 +77,6 @@ const (
 	DBSAck
 	// DBSDeploy is used by BP to create/drop/update database
 	DBSDeploy
-	// DBSGetRequest is used by observer to view original request
-	DBSGetRequest
 	// DBCCall is used by Miner for data consistency
 	DBCCall
 	// BPDBCreateDatabase is used by client to create database
@@ -93,14 +91,10 @@ const (
 	SQLCAdviseNewBlock
 	// SQLCAdviseBinLog is usd by sqlchain to advise binlog between adjacent node
 	SQLCAdviseBinLog
-	// SQLCAdviseResponsedQuery is used by sqlchain to advice response query between adjacent node
-	SQLCAdviseResponsedQuery
-	// SQLCAdviseAckedQuery is used by sqlchain to advise response ack between adjacent node
+	// SQLCAdviseAckedQuery is used by sqlchain to advice response query between adjacent node
 	SQLCAdviseAckedQuery
 	// SQLCFetchBlock is used by sqlchain to fetch block from adjacent nodes
 	SQLCFetchBlock
-	// SQLCFetchAckedQuery is used by sqlchain to fetch response ack from adjacent nodes
-	SQLCFetchAckedQuery
 	// SQLCSignBilling is used by sqlchain to response billing signature for periodic billing request
 	SQLCSignBilling
 	// SQLCLaunchBilling is used by blockproducer to trigger the billing process in sqlchain
@@ -109,8 +103,6 @@ const (
 	SQLCSubscribeTransactions
 	// SQLCCancelSubscription is used by sqlchain to handle observer subscription cancellation request
 	SQLCCancelSubscription
-	// OBSAdviseAckedQuery is used by sqlchain to push acked query to observers
-	OBSAdviseAckedQuery
 	// OBSAdviseNewBlock is used by sqlchain to push new block to observers
 	OBSAdviseNewBlock
 	// MCCAdviseNewBlock is used by block producer to push block to adjacent nodes
@@ -167,8 +159,6 @@ func (s RemoteFunc) String() string {
 		return "DBS.Ack"
 	case DBSDeploy:
 		return "DBS.Deploy"
-	case DBSGetRequest:
-		return "DBS.GetRequest"
 	case DBCCall:
 		return "DBC.Call"
 	case BPDBCreateDatabase:
@@ -183,14 +173,10 @@ func (s RemoteFunc) String() string {
 		return "SQLC.AdviseNewBlock"
 	case SQLCAdviseBinLog:
 		return "SQLC.AdviseBinLog"
-	case SQLCAdviseResponsedQuery:
-		return "SQLC.AdviseResponsedQuery"
 	case SQLCAdviseAckedQuery:
 		return "SQLC.AdviseAckedQuery"
 	case SQLCFetchBlock:
 		return "SQLC.FetchBlock"
-	case SQLCFetchAckedQuery:
-		return "SQLC.FetchAckedQuery"
 	case SQLCSignBilling:
 		return "SQLC.SignBilling"
 	case SQLCLaunchBilling:
@@ -199,8 +185,6 @@ func (s RemoteFunc) String() string {
 		return "SQLC.SubscribeTransactions"
 	case SQLCCancelSubscription:
 		return "SQLC.CancelSubscription"
-	case OBSAdviseAckedQuery:
-		return "OBS.AdviseAckedQuery"
 	case OBSAdviseNewBlock:
 		return "OBS.AdviseNewBlock"
 	case MCCAdviseNewBlock:
diff --git a/route/service.go b/route/service.go
index ad7d34da7..b02725380 100644
--- a/route/service.go
+++ b/route/service.go
@@ -50,7 +50,7 @@ func NewDHTService(DHTStorePath string, persistImpl consistent.Persistence, init
 }
 
 // Nil RPC does nothing just for probe
-func (DHT *DHTService) Nil(req *proto.PingReq, resp *proto.PingResp) (err error) {
+func (DHT *DHTService) Nil(req *interface{}, resp *interface{}) (err error) {
 	return
 }
 
diff --git a/rpc/leak_test.go b/rpc/leak_test.go
index d90f4fe83..91b96159c 100644
--- a/rpc/leak_test.go
+++ b/rpc/leak_test.go
@@ -43,7 +43,8 @@ func TestSessionPool_SessionBroken(t *testing.T) {
 	os.Remove(FJ(testWorkingDir, "./leak/leader/dht.db"))
 	os.Remove(FJ(testWorkingDir, "./leak/leader/dht.db-shm"))
 	os.Remove(FJ(testWorkingDir, "./leak/leader/dht.db-wal"))
-	os.Remove(FJ(testWorkingDir, "./leak/leader/kayak.db"))
+	os.Remove(FJ(testWorkingDir, "./leak/kayak.db"))
+	os.RemoveAll(FJ(testWorkingDir, "./leak/kayak.ldb"))
 
 	leader, err := utils.RunCommandNB(
 		FJ(baseDir, "./bin/cqld"),
diff --git a/rpc/rpcutil.go b/rpc/rpcutil.go
index cafd60d43..d39b12c86 100644
--- a/rpc/rpcutil.go
+++ b/rpc/rpcutil.go
@@ -61,12 +61,12 @@ func NewPersistentCaller(target proto.NodeID) *PersistentCaller {
 	}
 }
 
-func (c *PersistentCaller) initClient(method string) (err error) {
+func (c *PersistentCaller) initClient(isAnonymous bool) (err error) {
 	c.Lock()
 	defer c.Unlock()
 	if c.client == nil {
 		var conn net.Conn
-		conn, err = DialToNode(c.TargetID, c.pool, method == route.DHTPing.String())
+		conn, err = DialToNode(c.TargetID, c.pool, isAnonymous)
 		if err != nil {
 			log.WithField("target", c.TargetID).WithError(err).Error("dial to node failed")
 			return
@@ -83,28 +83,21 @@ func (c *PersistentCaller) initClient(method string) (err error) {
 
 // Call invokes the named function, waits for it to complete, and returns its error status.
 func (c *PersistentCaller) Call(method string, args interface{}, reply interface{}) (err error) {
-	err = c.initClient(method)
+	err = c.initClient(method == route.DHTPing.String())
 	if err != nil {
 		log.WithError(err).Error("init PersistentCaller client failed")
 		return
 	}
 	err = c.client.Call(method, args, reply)
 	if err != nil {
-		if err == io.EOF || err == io.ErrUnexpectedEOF {
+		if err == io.EOF ||
+			err == io.ErrUnexpectedEOF ||
+			err == io.ErrClosedPipe ||
+			err == rpc.ErrShutdown {
 			// if got EOF, retry once
-			c.Lock()
-			c.Close()
-			c.client = nil
-			c.Unlock()
-			err = c.initClient(method)
+			err = c.Reconnect(method)
 			if err != nil {
-				log.WithField("rpc", method).WithError(err).Error("second init client for RPC failed")
-				return
-			}
-			err = c.client.Call(method, args, reply)
-			if err != nil {
-				log.WithField("rpc", method).WithError(err).Error("second time call RPC failed")
-				return
+				log.WithField("rpc", method).WithError(err).Error("reconnect failed")
 			}
 		}
 		log.WithField("rpc", method).WithError(err).Error("call RPC failed")
@@ -112,6 +105,20 @@ func (c *PersistentCaller) Call(method string, args interface{}, reply interface
 	return
 }
 
+// Reconnect tries to rebuild RPC client
+func (c *PersistentCaller) Reconnect(method string) (err error)  {
+	c.Lock()
+	c.Close()
+	c.client = nil
+	c.Unlock()
+	err = c.initClient(method == route.DHTPing.String())
+	if err != nil {
+		log.WithField("rpc", method).WithError(err).Error("second init client for RPC failed")
+		return
+	}
+	return
+}
+
 // CloseStream closes the stream and RPC client
 func (c *PersistentCaller) CloseStream() {
 	if c.client != nil {
diff --git a/rpc/rpcutil_test.go b/rpc/rpcutil_test.go
index c3442336c..13c786a28 100644
--- a/rpc/rpcutil_test.go
+++ b/rpc/rpcutil_test.go
@@ -342,20 +342,28 @@ func BenchmarkPersistentCaller_Call(b *testing.B) {
 
 	client = NewPersistentCaller(conf.GConf.BP.NodeID)
 	b.Run("benchmark Persistent Call Nil", func(b *testing.B) {
-		var (
-			req  proto.PingReq
-			resp proto.PingResp
-		)
-
 		b.ResetTimer()
 		for i := 0; i < b.N; i++ {
-			err = client.Call("DHT.Nil", &req, &resp)
+			err = client.Call("DHT.Nil", nil, nil)
 			if err != nil {
 				b.Error(err)
 			}
 		}
 	})
 
+	b.Run("benchmark Persistent Call parallel Nil", func(b *testing.B) {
+
+		b.ResetTimer()
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				err := client.Call("DHT.Nil", nil, nil)
+				if err != nil {
+					b.Error(err)
+				}
+			}
+		})
+	})
+
 	req := &proto.FindNeighborReq{
 		ID:    "1234567812345678123456781234567812345678123456781234567812345678",
 		Count: 10,
diff --git a/sqlchain/ackindex.go b/sqlchain/ackindex.go
new file mode 100644
index 000000000..8e84d8bf5
--- /dev/null
+++ b/sqlchain/ackindex.go
@@ -0,0 +1,239 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sqlchain
+
+import (
+	"sync"
+	"sync/atomic"
+
+	"github.com/CovenantSQL/CovenantSQL/types"
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
+	"github.com/pkg/errors"
+)
+
+var (
+	// Global atomic counters for stats
+	multiIndexCount int32
+	responseCount   int32
+	ackTrackerCount int32
+)
+
+type ackTracker struct {
+	resp *types.SignedResponseHeader
+	ack  *types.SignedAckHeader
+}
+
+type multiAckIndex struct {
+	sync.RWMutex
+	ri map[types.QueryKey]*types.SignedResponseHeader // ri is the index of queries without acks
+	qi map[types.QueryKey]*ackTracker                 // qi is the index of query trackers
+}
+
+func (i *multiAckIndex) addResponse(resp *types.SignedResponseHeader) (err error) {
+	var key = resp.ResponseHeader.Request.GetQueryKey()
+	log.Debugf("Adding key %s <-- resp %s", &key, resp.Hash())
+	i.Lock()
+	defer i.Unlock()
+	if oresp, ok := i.ri[key]; ok {
+		if oresp.Hash() != resp.Hash() {
+			err = errors.Wrapf(ErrResponseSeqNotMatch, "add key %s <-- resp %s", &key, resp.Hash())
+			return
+		}
+		return
+	}
+	i.ri[key] = resp
+	atomic.AddInt32(&responseCount, 1)
+	return
+}
+
+func (i *multiAckIndex) register(ack *types.SignedAckHeader) (err error) {
+	var (
+		resp *types.SignedResponseHeader
+		ok   bool
+		key  = ack.SignedRequestHeader().GetQueryKey()
+	)
+	log.Debugf("Registering key %s <-- ack %s", &key, ack.Hash())
+
+	i.Lock()
+	defer i.Unlock()
+	if resp, ok = i.ri[key]; !ok {
+		err = errors.Wrapf(ErrQueryNotFound, "register key %s <-- ack %s", &key, ack.Hash())
+		return
+	}
+	delete(i.ri, key)
+	i.qi[key] = &ackTracker{
+		resp: resp,
+		ack:  ack,
+	}
+	atomic.AddInt32(&responseCount, -1)
+	atomic.AddInt32(&ackTrackerCount, 1)
+	return
+}
+
+func (i *multiAckIndex) remove(ack *types.SignedAckHeader) (err error) {
+	var key = ack.SignedRequestHeader().GetQueryKey()
+	log.Debugf("Removing key %s -x- ack %s", &key, ack.Hash())
+	i.Lock()
+	defer i.Unlock()
+	if _, ok := i.ri[key]; ok {
+		delete(i.ri, key)
+		atomic.AddInt32(&responseCount, -1)
+		return
+	}
+	if oack, ok := i.qi[key]; ok {
+		if oack.ack.Hash() != ack.Hash() {
+			err = errors.Wrapf(
+				ErrMultipleAckOfSeqNo, "remove key %s -x- ack %s", &key, ack.Hash())
+			return
+		}
+		delete(i.qi, key)
+		atomic.AddInt32(&ackTrackerCount, -1)
+		return
+	}
+	err = errors.Wrapf(ErrQueryNotFound, "remove key %s -x- ack %s", &key, ack.Hash())
+	return
+}
+
+func (i *multiAckIndex) acks() (ret []*types.SignedAckHeader) {
+	i.RLock()
+	defer i.RUnlock()
+	for _, v := range i.qi {
+		ret = append(ret, v.ack)
+	}
+	return
+}
+
+func (i *multiAckIndex) expire() {
+	i.RLock()
+	defer i.RUnlock()
+	// TODO(leventeliu): need further processing.
+	for _, v := range i.ri {
+		log.WithFields(log.Fields{
+			"request_hash":  v.Request.Hash(),
+			"request_time":  v.Request.Timestamp,
+			"request_type":  v.Request.QueryType,
+			"request_node":  v.Request.NodeID,
+			"response_hash": v.Hash(),
+			"response_node": v.NodeID,
+			"response_time": v.Timestamp,
+		}).Warn("Query expires without acknowledgement")
+	}
+	for _, v := range i.qi {
+		log.WithFields(log.Fields{
+			"request_hash":  v.resp.Request.Hash(),
+			"request_time":  v.resp.Request.Timestamp,
+			"request_type":  v.resp.Request.QueryType,
+			"request_node":  v.resp.Request.NodeID,
+			"response_hash": v.ack.Response.Hash(),
+			"response_node": v.ack.Response.NodeID,
+			"response_time": v.ack.Response.Timestamp,
+			"ack_hash":      v.ack.Hash(),
+			"ack_node":      v.ack.NodeID,
+			"ack_time":      v.ack.Timestamp,
+		}).Warn("Query expires without block producing")
+	}
+}
+
+type ackIndex struct {
+	hi map[int32]*multiAckIndex
+
+	sync.RWMutex
+	barrier int32
+}
+
+func newAckIndex() *ackIndex {
+	return &ackIndex{
+		hi: make(map[int32]*multiAckIndex),
+	}
+}
+
+func (i *ackIndex) load(h int32) (mi *multiAckIndex, err error) {
+	var ok bool
+	i.Lock()
+	defer i.Unlock()
+	if h < i.barrier {
+		err = errors.Wrapf(ErrQueryExpired, "loading index at height %d barrier %d", h, i.barrier)
+		return
+	}
+	if mi, ok = i.hi[h]; !ok {
+		mi = &multiAckIndex{
+			ri: make(map[types.QueryKey]*types.SignedResponseHeader),
+			qi: make(map[types.QueryKey]*ackTracker),
+		}
+		i.hi[h] = mi
+		atomic.AddInt32(&multiIndexCount, 1)
+	}
+	return
+}
+
+func (i *ackIndex) advance(h int32) {
+	var dl []*multiAckIndex
+	i.Lock()
+	for x := i.barrier; x < h; x++ {
+		if mi, ok := i.hi[x]; ok {
+			dl = append(dl, mi)
+		}
+		delete(i.hi, x)
+	}
+	i.barrier = h
+	i.Unlock()
+	// Record expired and not acknowledged queries
+	for _, v := range dl {
+		v.expire()
+		atomic.AddInt32(&responseCount, int32(-len(v.ri)))
+		atomic.AddInt32(&ackTrackerCount, int32(-len(v.qi)))
+	}
+	atomic.AddInt32(&multiIndexCount, int32(-len(dl)))
+}
+
+func (i *ackIndex) addResponse(h int32, resp *types.SignedResponseHeader) (err error) {
+	var mi *multiAckIndex
+	if mi, err = i.load(h); err != nil {
+		return
+	}
+	return mi.addResponse(resp)
+}
+
+func (i *ackIndex) register(h int32, ack *types.SignedAckHeader) (err error) {
+	var mi *multiAckIndex
+	if mi, err = i.load(h); err != nil {
+		return
+	}
+	return mi.register(ack)
+}
+
+func (i *ackIndex) remove(h int32, ack *types.SignedAckHeader) (err error) {
+	var mi *multiAckIndex
+	if mi, err = i.load(h); err != nil {
+		return
+	}
+	return mi.remove(ack)
+}
+
+func (i *ackIndex) acks(h int32) (ret []*types.SignedAckHeader) {
+	var b = func() int32 {
+		i.RLock()
+		defer i.RUnlock()
+		return i.barrier
+	}()
+	for x := b; x <= h; x++ {
+		if mi, err := i.load(x); err == nil {
+			ret = append(ret, mi.acks()...)
+		}
+	}
+	return
+}
diff --git a/sqlchain/ackindex_test.go b/sqlchain/ackindex_test.go
new file mode 100644
index 000000000..77ccd4d18
--- /dev/null
+++ b/sqlchain/ackindex_test.go
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sqlchain
+
+import (
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/types"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestAckIndex(t *testing.T) {
+	Convey("Given a ackIndex instance", t, func() {
+		var (
+			err error
+
+			ai   = newAckIndex()
+			resp = &types.SignedResponseHeader{
+				ResponseHeader: types.ResponseHeader{
+					Request: types.SignedRequestHeader{
+						RequestHeader: types.RequestHeader{
+							NodeID: proto.NodeID(
+								"0000000000000000000000000000000000000000000000000000000000000000"),
+							ConnectionID: 0,
+							SeqNo:        0,
+						},
+					},
+				},
+			}
+			ack = &types.SignedAckHeader{
+				AckHeader: types.AckHeader{
+					Response: *resp,
+				},
+			}
+		)
+		Convey("Add response and register ack should return no error", func() {
+			err = ai.addResponse(0, resp)
+			So(err, ShouldBeNil)
+			err = ai.register(0, ack)
+			So(err, ShouldBeNil)
+			err = ai.remove(0, ack)
+			So(err, ShouldBeNil)
+		})
+	})
+}
diff --git a/sqlchain/blockindex.go b/sqlchain/blockindex.go
index c2333a1e1..04bf7d97f 100644
--- a/sqlchain/blockindex.go
+++ b/sqlchain/blockindex.go
@@ -21,18 +21,18 @@ import (
 	"sync"
 
 	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 )
 
 type blockNode struct {
 	parent *blockNode
-	block  *ct.Block // TODO(leventeliu): cleanup history blocks to release memory.
+	block  *types.Block
 	hash   hash.Hash
 	height int32 // height is the chain height of the head
 	count  int32 // count counts the blocks (except genesis) at this head
 }
 
-func newBlockNode(height int32, block *ct.Block, parent *blockNode) *blockNode {
+func newBlockNode(height int32, block *types.Block, parent *blockNode) *blockNode {
 	return &blockNode{
 		hash:   *block.BlockHash(),
 		parent: parent,
@@ -48,7 +48,7 @@ func newBlockNode(height int32, block *ct.Block, parent *blockNode) *blockNode {
 	}
 }
 
-func (n *blockNode) initBlockNode(height int32, block *ct.Block, parent *blockNode) {
+func (n *blockNode) initBlockNode(height int32, block *types.Block, parent *blockNode) {
 	n.block = block
 	n.hash = *block.BlockHash()
 	n.parent = nil
@@ -85,19 +85,14 @@ func (n *blockNode) indexKey() (key []byte) {
 }
 
 type blockIndex struct {
-	cfg *Config
-
 	mu    sync.RWMutex
 	index map[hash.Hash]*blockNode
 }
 
-func newBlockIndex(cfg *Config) (index *blockIndex) {
-	index = &blockIndex{
-		cfg:   cfg,
+func newBlockIndex() (index *blockIndex) {
+	return &blockIndex{
 		index: make(map[hash.Hash]*blockNode),
 	}
-
-	return index
 }
 
 func (i *blockIndex) addBlock(newBlock *blockNode) {
diff --git a/sqlchain/blockindex_test.go b/sqlchain/blockindex_test.go
index df47a4cdd..e372980c8 100644
--- a/sqlchain/blockindex_test.go
+++ b/sqlchain/blockindex_test.go
@@ -20,16 +20,16 @@ import (
 	"testing"
 
 	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 )
 
 var (
-	testBlocks      []*ct.Block
+	testBlocks      []*types.Block
 	testBlockNumber = 50
 )
 
 func generateTestBlocks() (err error) {
-	testBlocks = make([]*ct.Block, 0, testBlockNumber)
+	testBlocks = make([]*types.Block, 0, testBlockNumber)
 
 	for i, prev := 0, genesisHash; i < testBlockNumber; i++ {
 		b, err := createRandomBlock(prev, false)
@@ -108,8 +108,7 @@ func TestInitBlockNode(t *testing.T) {
 }
 
 func TestAncestor(t *testing.T) {
-	cfg := &Config{}
-	index := newBlockIndex(cfg)
+	index := newBlockIndex()
 	parent := (*blockNode)(nil)
 
 	for h, b := range testBlocks {
@@ -142,8 +141,7 @@ func TestAncestor(t *testing.T) {
 }
 
 func TestIndex(t *testing.T) {
-	cfg := &Config{}
-	index := newBlockIndex(cfg)
+	index := newBlockIndex()
 	parent := (*blockNode)(nil)
 
 	for h, b := range testBlocks {
diff --git a/sqlchain/chain.go b/sqlchain/chain.go
index 5fd0199ad..a95f81c45 100644
--- a/sqlchain/chain.go
+++ b/sqlchain/chain.go
@@ -21,27 +21,34 @@ import (
 	"encoding/binary"
 	"fmt"
 	"os"
+	rt "runtime"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	pt "github.com/CovenantSQL/CovenantSQL/blockproducer/types"
 	"github.com/CovenantSQL/CovenantSQL/crypto"
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
-	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
 	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
+	x "github.com/CovenantSQL/CovenantSQL/xenomint"
+	xi "github.com/CovenantSQL/CovenantSQL/xenomint/interfaces"
+	xs "github.com/CovenantSQL/CovenantSQL/xenomint/sqlite"
 	"github.com/pkg/errors"
 	"github.com/syndtr/goleveldb/leveldb"
 	"github.com/syndtr/goleveldb/leveldb/opt"
 	"github.com/syndtr/goleveldb/leveldb/util"
 )
 
+const (
+	minBlockCacheTTL = int32(30)
+)
+
 var (
 	metaState         = [4]byte{'S', 'T', 'A', 'T'}
 	metaBlockIndex    = [4]byte{'B', 'L', 'C', 'K'}
@@ -49,13 +56,21 @@ var (
 	metaResponseIndex = [4]byte{'R', 'E', 'S', 'P'}
 	metaAckIndex      = [4]byte{'Q', 'A', 'C', 'K'}
 	leveldbConf       = opt.Options{}
+
+	// Atomic counters for stats
+	cachedBlockCount int32
 )
 
 func init() {
 	leveldbConf.BlockSize = 4 * 1024 * 1024
 	leveldbConf.Compression = opt.SnappyCompression
-	leveldbConf.WriteBuffer = 64 * 1024 * 1024
-	leveldbConf.BlockCacheCapacity = 2 * leveldbConf.WriteBuffer
+}
+
+func statBlock(b *types.Block) {
+	atomic.AddInt32(&cachedBlockCount, 1)
+	rt.SetFinalizer(b, func(_ *types.Block) {
+		atomic.AddInt32(&cachedBlockCount, -1)
+	})
 }
 
 // heightToKey converts a height in int32 to a key in bytes.
@@ -93,15 +108,16 @@ type Chain struct {
 	// tdb stores ack/request/response
 	tdb *leveldb.DB
 	bi  *blockIndex
-	qi  *queryIndex
+	ai  *ackIndex
+	st  *x.State
 	cl  *rpc.Caller
 	rt  *runtime
 
 	stopCh    chan struct{}
-	blocks    chan *ct.Block
+	blocks    chan *types.Block
 	heights   chan int32
-	responses chan *wt.ResponseHeader
-	acks      chan *wt.AckHeader
+	responses chan *types.ResponseHeader
+	acks      chan *types.AckHeader
 
 	// DBAccount info
 	tokenType    pt.TokenType
@@ -118,6 +134,11 @@ type Chain struct {
 	replCh chan struct{}
 	// replWg defines the waitGroups for running replications.
 	replWg sync.WaitGroup
+
+	// Cached fileds, may need to renew some of this fields later.
+	//
+	// pk is the private key of the local miner.
+	pk *asymmetric.PrivateKey
 }
 
 // NewChain creates a new sql-chain struct.
@@ -125,7 +146,7 @@ func NewChain(c *Config) (chain *Chain, err error) {
 	// TODO(leventeliu): this is a rough solution, you may also want to clean database file and
 	// force rebuilding.
 	var fi os.FileInfo
-	if fi, err = os.Stat(c.DataFile + "-block-state.ldb"); err == nil && fi.Mode().IsDir() {
+	if fi, err = os.Stat(c.ChainFilePrefix + "-block-state.ldb"); err == nil && fi.Mode().IsDir() {
 		return LoadChain(c)
 	}
 
@@ -135,7 +156,7 @@ func NewChain(c *Config) (chain *Chain, err error) {
 	}
 
 	// Open LevelDB for block and state
-	bdbFile := c.DataFile + "-block-state.ldb"
+	bdbFile := c.ChainFilePrefix + "-block-state.ldb"
 	bdb, err := leveldb.OpenFile(bdbFile, &leveldbConf)
 	if err != nil {
 		err = errors.Wrapf(err, "open leveldb %s", bdbFile)
@@ -145,7 +166,7 @@ func NewChain(c *Config) (chain *Chain, err error) {
 	log.Debugf("Create new chain bdb %s", bdbFile)
 
 	// Open LevelDB for ack/request/response
-	tdbFile := c.DataFile + "-ack-req-resp.ldb"
+	tdbFile := c.ChainFilePrefix + "-ack-req-resp.ldb"
 	tdb, err := leveldb.OpenFile(tdbFile, &leveldbConf)
 	if err != nil {
 		err = errors.Wrapf(err, "open leveldb %s", tdbFile)
@@ -154,19 +175,39 @@ func NewChain(c *Config) (chain *Chain, err error) {
 
 	log.Debugf("Create new chain tdb %s", tdbFile)
 
+	// Open x.State
+	var (
+		strg  xi.Storage
+		state *x.State
+	)
+	if strg, err = xs.NewSqlite(c.DataFile); err != nil {
+		return
+	}
+	if state, err = x.NewState(c.Server, strg); err != nil {
+		return
+	}
+
+	// Cache local private key
+	var pk *asymmetric.PrivateKey
+	if pk, err = kms.GetLocalPrivateKey(); err != nil {
+		err = errors.Wrap(err, "failed to cache private key")
+		return
+	}
+
 	// Create chain state
 	chain = &Chain{
 		bdb:          bdb,
 		tdb:          tdb,
-		bi:           newBlockIndex(c),
-		qi:           newQueryIndex(),
+		bi:           newBlockIndex(),
+		ai:           newAckIndex(),
+		st:           state,
 		cl:           rpc.NewCaller(),
 		rt:           newRunTime(c),
 		stopCh:       make(chan struct{}),
-		blocks:       make(chan *ct.Block),
+		blocks:       make(chan *types.Block),
 		heights:      make(chan int32, 1),
-		responses:    make(chan *wt.ResponseHeader),
-		acks:         make(chan *wt.AckHeader),
+		responses:    make(chan *types.ResponseHeader),
+		acks:         make(chan *types.AckHeader),
 		tokenType:    c.TokenType,
 		gasPrice:     c.GasPrice,
 		updatePeriod: c.UpdatePeriod,
@@ -175,6 +216,8 @@ func NewChain(c *Config) (chain *Chain, err error) {
 		observers:           make(map[proto.NodeID]int32),
 		observerReplicators: make(map[proto.NodeID]*observerReplicator),
 		replCh:              make(chan struct{}),
+
+		pk: pk,
 	}
 
 	if err = chain.pushBlock(c.Genesis); err != nil {
@@ -187,7 +230,7 @@ func NewChain(c *Config) (chain *Chain, err error) {
 // LoadChain loads the chain state from the specified database and rebuilds a memory index.
 func LoadChain(c *Config) (chain *Chain, err error) {
 	// Open LevelDB for block and state
-	bdbFile := c.DataFile + "-block-state.ldb"
+	bdbFile := c.ChainFilePrefix + "-block-state.ldb"
 	bdb, err := leveldb.OpenFile(bdbFile, &leveldbConf)
 	if err != nil {
 		err = errors.Wrapf(err, "open leveldb %s", bdbFile)
@@ -195,26 +238,46 @@ func LoadChain(c *Config) (chain *Chain, err error) {
 	}
 
 	// Open LevelDB for ack/request/response
-	tdbFile := c.DataFile + "-ack-req-resp.ldb"
+	tdbFile := c.ChainFilePrefix + "-ack-req-resp.ldb"
 	tdb, err := leveldb.OpenFile(tdbFile, &leveldbConf)
 	if err != nil {
 		err = errors.Wrapf(err, "open leveldb %s", tdbFile)
 		return
 	}
 
+	// Open x.State
+	var (
+		strg   xi.Storage
+		xstate *x.State
+	)
+	if strg, err = xs.NewSqlite(c.DataFile); err != nil {
+		return
+	}
+	if xstate, err = x.NewState(c.Server, strg); err != nil {
+		return
+	}
+
+	// Cache local private key
+	var pk *asymmetric.PrivateKey
+	if pk, err = kms.GetLocalPrivateKey(); err != nil {
+		err = errors.Wrap(err, "failed to cache private key")
+		return
+	}
+
 	// Create chain state
 	chain = &Chain{
 		bdb:          bdb,
 		tdb:          tdb,
-		bi:           newBlockIndex(c),
-		qi:           newQueryIndex(),
+		bi:           newBlockIndex(),
+		ai:           newAckIndex(),
+		st:           xstate,
 		cl:           rpc.NewCaller(),
 		rt:           newRunTime(c),
 		stopCh:       make(chan struct{}),
-		blocks:       make(chan *ct.Block),
+		blocks:       make(chan *types.Block),
 		heights:      make(chan int32, 1),
-		responses:    make(chan *wt.ResponseHeader),
-		acks:         make(chan *wt.AckHeader),
+		responses:    make(chan *types.ResponseHeader),
+		acks:         make(chan *types.AckHeader),
 		tokenType:    c.TokenType,
 		gasPrice:     c.GasPrice,
 		updatePeriod: c.UpdatePeriod,
@@ -223,6 +286,8 @@ func LoadChain(c *Config) (chain *Chain, err error) {
 		observers:           make(map[proto.NodeID]int32),
 		observerReplicators: make(map[proto.NodeID]*observerReplicator),
 		replCh:              make(chan struct{}),
+
+		pk: pk,
 	}
 
 	// Read state struct
@@ -242,6 +307,7 @@ func LoadChain(c *Config) (chain *Chain, err error) {
 
 	// Read blocks and rebuild memory index
 	var (
+		id        uint64
 		index     int32
 		last      *blockNode
 		blockIter = chain.bdb.NewIterator(util.BytesPrefix(metaBlockIndex[:]), nil)
@@ -251,7 +317,7 @@ func LoadChain(c *Config) (chain *Chain, err error) {
 		var (
 			k     = blockIter.Key()
 			v     = blockIter.Value()
-			block = &ct.Block{}
+			block = &types.Block{}
 
 			current, parent *blockNode
 		)
@@ -286,6 +352,11 @@ func LoadChain(c *Config) (chain *Chain, err error) {
 			}
 		}
 
+		// Update id
+		if nid, ok := block.CalcNextID(); ok && nid > id {
+			id = nid
+		}
+
 		current = &blockNode{}
 		current.initBlockNode(chain.rt.getHeightFromTime(block.Timestamp()), block, parent)
 		chain.bi.addBlock(current)
@@ -299,6 +370,8 @@ func LoadChain(c *Config) (chain *Chain, err error) {
 	// Set chain state
 	st.node = last
 	chain.rt.setHead(st)
+	chain.st.InitTx(id)
+	chain.pruneBlockCache()
 
 	// Read queries and rebuild memory index
 	respIter := chain.tdb.NewIterator(util.BytesPrefix(metaResponseIndex[:]), nil)
@@ -307,20 +380,15 @@ func LoadChain(c *Config) (chain *Chain, err error) {
 		k := respIter.Key()
 		v := respIter.Value()
 		h := keyWithSymbolToHeight(k)
-		var resp = &wt.SignedResponseHeader{}
+		var resp = &types.SignedResponseHeader{}
 		if err = utils.DecodeMsgPack(v, resp); err != nil {
 			err = errors.Wrapf(err, "load resp, height %d, index %s", h, string(k))
 			return
 		}
 		log.WithFields(log.Fields{
 			"height": h,
-			"header": resp.Hash.String(),
+			"header": resp.Hash().String(),
 		}).Debug("Loaded new resp header")
-		err = chain.qi.addResponse(h, resp)
-		if err != nil {
-			err = errors.Wrapf(err, "load resp, height %d, hash %s", h, resp.Hash.String())
-			return
-		}
 	}
 	if err = respIter.Error(); err != nil {
 		err = errors.Wrap(err, "load resp")
@@ -333,20 +401,15 @@ func LoadChain(c *Config) (chain *Chain, err error) {
 		k := ackIter.Key()
 		v := ackIter.Value()
 		h := keyWithSymbolToHeight(k)
-		var ack = &wt.SignedAckHeader{}
+		var ack = &types.SignedAckHeader{}
 		if err = utils.DecodeMsgPack(v, ack); err != nil {
 			err = errors.Wrapf(err, "load ack, height %d, index %s", h, string(k))
 			return
 		}
 		log.WithFields(log.Fields{
 			"height": h,
-			"header": ack.Hash.String(),
+			"header": ack.Hash().String(),
 		}).Debug("Loaded new ack header")
-		err = chain.qi.addAck(h, ack)
-		if err != nil {
-			err = errors.Wrapf(err, "load ack, height %d, hash %s", h, ack.Hash.String())
-			return
-		}
 	}
 	if err = respIter.Error(); err != nil {
 		err = errors.Wrap(err, "load ack")
@@ -357,7 +420,7 @@ func LoadChain(c *Config) (chain *Chain, err error) {
 }
 
 // pushBlock pushes the signed block header to extend the current main chain.
-func (c *Chain) pushBlock(b *ct.Block) (err error) {
+func (c *Chain) pushBlock(b *types.Block) (err error) {
 	// Prepare and encode
 	h := c.rt.getHeightFromTime(b.Timestamp())
 	node := newBlockNode(h, b, c.rt.getHead().node)
@@ -396,58 +459,55 @@ func (c *Chain) pushBlock(b *ct.Block) (err error) {
 	}
 	c.rt.setHead(st)
 	c.bi.addBlock(node)
-	c.qi.setSignedBlock(h, b)
+
+	// Keep track of the queries from the new block
+	var ierr error
+	for i, v := range b.QueryTxs {
+		if ierr = c.addResponse(v.Response); ierr != nil {
+			log.WithFields(log.Fields{
+				"index":      i,
+				"producer":   b.Producer(),
+				"block_hash": b.BlockHash(),
+			}).WithError(ierr).Warn("Failed to add response to ackIndex")
+		}
+	}
+	for i, v := range b.Acks {
+		if ierr = c.remove(v); ierr != nil {
+			log.WithFields(log.Fields{
+				"index":      i,
+				"producer":   b.Producer(),
+				"block_hash": b.BlockHash(),
+			}).WithError(ierr).Warn("Failed to remove Ack from ackIndex")
+		}
+	}
 
 	if err == nil {
 		log.WithFields(log.Fields{
-			"peer":        c.rt.getPeerInfoString()[:14],
-			"time":        c.rt.getChainTimeString(),
-			"block":       b.BlockHash().String()[:8],
-			"producer":    b.Producer()[:8],
-			"querycount":  len(b.Queries),
-			"blocktime":   b.Timestamp().Format(time.RFC3339Nano),
-			"blockheight": c.rt.getHeightFromTime(b.Timestamp()),
-			"headblock": fmt.Sprintf("%s <- %s",
+			"peer":       c.rt.getPeerInfoString()[:14],
+			"time":       c.rt.getChainTimeString(),
+			"block":      b.BlockHash().String()[:8],
+			"producer":   b.Producer()[:8],
+			"queryCount": len(b.QueryTxs),
+			"ackCount":   len(b.Acks),
+			"blockTime":  b.Timestamp().Format(time.RFC3339Nano),
+			"height":     c.rt.getHeightFromTime(b.Timestamp()),
+			"head": fmt.Sprintf("%s <- %s",
 				func() string {
 					if st.node.parent != nil {
 						return st.node.parent.hash.String()[:8]
 					}
 					return "|"
 				}(), st.Head.String()[:8]),
-			"headheight": c.rt.getHead().Height,
+			"headHeight": c.rt.getHead().Height,
 		}).Info("Pushed new block")
 	}
 
 	return
 }
 
-// pushResponedQuery pushes a responsed, signed and verified query into the chain.
-func (c *Chain) pushResponedQuery(resp *wt.SignedResponseHeader) (err error) {
-	h := c.rt.getHeightFromTime(resp.Request.Timestamp)
-	k := heightToKey(h)
-	var enc *bytes.Buffer
-
-	if enc, err = utils.EncodeMsgPack(resp); err != nil {
-		return
-	}
-
-	tdbKey := utils.ConcatAll(metaResponseIndex[:], k, resp.Hash[:])
-	if err = c.tdb.Put(tdbKey, enc.Bytes(), nil); err != nil {
-		err = errors.Wrapf(err, "put response %d %s", h, resp.Hash.String())
-		return
-	}
-
-	if err = c.qi.addResponse(h, resp); err != nil {
-		err = errors.Wrapf(err, "add resp h %d hash %s", h, resp.Hash)
-		return err
-	}
-
-	return
-}
-
 // pushAckedQuery pushes a acknowledged, signed and verified query into the chain.
-func (c *Chain) pushAckedQuery(ack *wt.SignedAckHeader) (err error) {
-	log.Debugf("push ack %s", ack.Hash.String())
+func (c *Chain) pushAckedQuery(ack *types.SignedAckHeader) (err error) {
+	log.Debugf("push ack %s", ack.Hash().String())
 	h := c.rt.getHeightFromTime(ack.SignedResponseHeader().Timestamp)
 	k := heightToKey(h)
 	var enc *bytes.Buffer
@@ -456,34 +516,33 @@ func (c *Chain) pushAckedQuery(ack *wt.SignedAckHeader) (err error) {
 		return
 	}
 
-	tdbKey := utils.ConcatAll(metaAckIndex[:], k, ack.Hash[:])
+	tdbKey := utils.ConcatAll(metaAckIndex[:], k, ack.Hash().AsBytes())
 
 	if err = c.tdb.Put(tdbKey, enc.Bytes(), nil); err != nil {
-		err = errors.Wrapf(err, "put ack %d %s", h, ack.Hash.String())
+		err = errors.Wrapf(err, "put ack %d %s", h, ack.Hash().String())
 		return
 	}
 
-	if err = c.qi.addAck(h, ack); err != nil {
-		err = errors.Wrapf(err, "add ack h %d hash %s", h, ack.Hash)
-		return err
+	if err = c.register(ack); err != nil {
+		err = errors.Wrapf(err, "register ack %v at height %d", ack.Hash(), h)
+		return
 	}
 
 	return
 }
 
-// produceBlock prepares, signs and advises the pending block to the orther peers.
-func (c *Chain) produceBlock(now time.Time) (err error) {
-	// Retrieve local key pair
-	priv, err := kms.GetLocalPrivateKey()
-
-	if err != nil {
+// produceBlockV2 prepares, signs and advises the pending block to the other peers.
+func (c *Chain) produceBlockV2(now time.Time) (err error) {
+	var (
+		frs []*types.Request
+		qts []*x.QueryTracker
+	)
+	if frs, qts, err = c.st.CommitEx(); err != nil {
 		return
 	}
-
-	// Pack and sign block
-	block := &ct.Block{
-		SignedHeader: ct.SignedHeader{
-			Header: ct.Header{
+	var block = &types.Block{
+		SignedHeader: types.SignedHeader{
+			Header: types.Header{
 				Version:     0x01000000,
 				Producer:    c.rt.getServer(),
 				GenesisHash: c.rt.genesisHash,
@@ -491,15 +550,27 @@ func (c *Chain) produceBlock(now time.Time) (err error) {
 				// MerkleRoot: will be set by Block.PackAndSignBlock(PrivateKey)
 				Timestamp: now,
 			},
-			// BlockHash/Signee/Signature: will be set by Block.PackAndSignBlock(PrivateKey)
 		},
-		Queries: c.qi.markAndCollectUnsignedAcks(c.rt.getNextTurn()),
+		FailedReqs: frs,
+		QueryTxs:   make([]*types.QueryAsTx, len(qts)),
+		Acks:       c.ai.acks(c.rt.getHeightFromTime(now)),
+	}
+	statBlock(block)
+	for i, v := range qts {
+		// TODO(leventeliu): maybe block waiting at a ready channel instead?
+		for !v.Ready() {
+			time.Sleep(1 * time.Millisecond)
+		}
+		block.QueryTxs[i] = &types.QueryAsTx{
+			// TODO(leventeliu): add acks for billing.
+			Request:  v.Req,
+			Response: &v.Resp.Header,
+		}
 	}
-
-	if err = block.PackAndSignBlock(priv); err != nil {
+	// Sign block
+	if err = block.PackAndSignBlock(c.pk); err != nil {
 		return
 	}
-
 	// Send to pending list
 	c.blocks <- block
 	log.WithFields(log.Fields{
@@ -509,29 +580,29 @@ func (c *Chain) produceBlock(now time.Time) (err error) {
 		"using_timestamp": now.Format(time.RFC3339Nano),
 		"block_hash":      block.BlockHash().String(),
 	}).Debug("Produced new block")
-
 	// Advise new block to the other peers
-	req := &MuxAdviseNewBlockReq{
-		Envelope: proto.Envelope{
-			// TODO(leventeliu): Add fields.
-		},
-		DatabaseID: c.rt.databaseID,
-		AdviseNewBlockReq: AdviseNewBlockReq{
-			Block: block,
-			Count: func() int32 {
-				if nd := c.bi.lookupNode(block.BlockHash()); nd != nil {
-					return nd.count
-				}
-				if pn := c.bi.lookupNode(block.ParentHash()); pn != nil {
-					return pn.count + 1
-				}
-				return -1
-			}(),
-		},
-	}
-	peers := c.rt.getPeers()
-	wg := &sync.WaitGroup{}
-
+	var (
+		req = &MuxAdviseNewBlockReq{
+			Envelope: proto.Envelope{
+				// TODO(leventeliu): Add fields.
+			},
+			DatabaseID: c.rt.databaseID,
+			AdviseNewBlockReq: AdviseNewBlockReq{
+				Block: block,
+				Count: func() int32 {
+					if nd := c.bi.lookupNode(block.BlockHash()); nd != nil {
+						return nd.count
+					}
+					if pn := c.bi.lookupNode(block.ParentHash()); pn != nil {
+						return pn.count + 1
+					}
+					return -1
+				}(),
+			},
+		}
+		peers = c.rt.getPeers()
+		wg    = &sync.WaitGroup{}
+	)
 	for _, s := range peers.Servers {
 		if s != c.rt.getServer() {
 			wg.Add(1)
@@ -552,12 +623,9 @@ func (c *Chain) produceBlock(now time.Time) (err error) {
 			}(s)
 		}
 	}
-
 	wg.Wait()
-
 	// fire replication to observers
 	c.startStopReplication()
-
 	return
 }
 
@@ -593,6 +661,7 @@ func (c *Chain) syncHead() {
 					}).WithError(err).Debug(
 						"Failed to fetch block from peer")
 				} else {
+					statBlock(resp.Block)
 					c.blocks <- resp.Block
 					log.WithFields(log.Fields{
 						"peer":        c.rt.getPeerInfoString(),
@@ -625,8 +694,10 @@ func (c *Chain) syncHead() {
 // runCurrentTurn does the check and runs block producing if its my turn.
 func (c *Chain) runCurrentTurn(now time.Time) {
 	defer func() {
+		c.stat()
+		c.pruneBlockCache()
 		c.rt.setNextTurn()
-		c.qi.advanceBarrier(c.rt.getMinValidHeight())
+		c.ai.advance(c.rt.getMinValidHeight())
 		// Info the block processing goroutine that the chain height has grown, so please return
 		// any stashed blocks for further check.
 		c.heights <- c.rt.getHead().Height
@@ -656,7 +727,7 @@ func (c *Chain) runCurrentTurn(now time.Time) {
 		return
 	}
 
-	if err := c.produceBlock(now); err != nil {
+	if err := c.produceBlockV2(now); err != nil {
 		log.WithFields(log.Fields{
 			"peer":            c.rt.getPeerInfoString(),
 			"time":            c.rt.getChainTimeString(),
@@ -727,7 +798,7 @@ func (c *Chain) sync() (err error) {
 func (c *Chain) processBlocks() {
 	rsCh := make(chan struct{})
 	rsWG := &sync.WaitGroup{}
-	returnStash := func(stash []*ct.Block) {
+	returnStash := func(stash []*types.Block) {
 		defer rsWG.Done()
 		for _, block := range stash {
 			select {
@@ -744,7 +815,7 @@ func (c *Chain) processBlocks() {
 		c.rt.wg.Done()
 	}()
 
-	var stash []*ct.Block
+	var stash []*types.Block
 	for {
 		select {
 		case h := <-c.heights:
@@ -854,21 +925,34 @@ func (c *Chain) Stop() (err error) {
 		"time": c.rt.getChainTimeString(),
 	}).Debug("Chain service stopped")
 	// Close LevelDB file
-	err = c.bdb.Close()
+	var ierr error
+	if ierr = c.bdb.Close(); ierr != nil && err == nil {
+		err = ierr
+	}
+	log.WithFields(log.Fields{
+		"peer": c.rt.getPeerInfoString(),
+		"time": c.rt.getChainTimeString(),
+	}).WithError(ierr).Debug("Chain database closed")
+	if ierr = c.tdb.Close(); ierr != nil && err == nil {
+		err = ierr
+	}
 	log.WithFields(log.Fields{
 		"peer": c.rt.getPeerInfoString(),
 		"time": c.rt.getChainTimeString(),
-	}).Debug("Chain database closed")
-	err = c.tdb.Close()
+	}).WithError(ierr).Debug("Chain database closed")
+	// Close state
+	if ierr = c.st.Close(false); ierr != nil && err == nil {
+		err = ierr
+	}
 	log.WithFields(log.Fields{
 		"peer": c.rt.getPeerInfoString(),
 		"time": c.rt.getChainTimeString(),
-	}).Debug("Chain database closed")
+	}).WithError(ierr).Debug("Chain state storage closed")
 	return
 }
 
 // FetchBlock fetches the block at specified height from local cache.
-func (c *Chain) FetchBlock(height int32) (b *ct.Block, err error) {
+func (c *Chain) FetchBlock(height int32) (b *types.Block, err error) {
 	if n := c.rt.getHead().node.ancestor(height); n != nil {
 		k := utils.ConcatAll(metaBlockIndex[:], n.indexKey())
 		var v []byte
@@ -878,7 +962,8 @@ func (c *Chain) FetchBlock(height int32) (b *ct.Block, err error) {
 			return
 		}
 
-		b = &ct.Block{}
+		b = &types.Block{}
+		statBlock(b)
 		err = utils.DecodeMsgPack(v, b)
 		if err != nil {
 			err = errors.Wrapf(err, "fetch block %s", string(k))
@@ -889,86 +974,8 @@ func (c *Chain) FetchBlock(height int32) (b *ct.Block, err error) {
 	return
 }
 
-// FetchAckedQuery fetches the acknowledged query from local cache.
-func (c *Chain) FetchAckedQuery(height int32, header *hash.Hash) (
-	ack *wt.SignedAckHeader, err error,
-) {
-	if ack, err = c.qi.getAck(height, header); err != nil || ack == nil {
-		for h := height - c.rt.queryTTL - 1; h <= height; h++ {
-			k := heightToKey(h)
-			ackKey := utils.ConcatAll(metaAckIndex[:], k, header[:])
-			var v []byte
-			if v, err = c.tdb.Get(ackKey, nil); err != nil {
-				// if err == leveldb.ErrNotFound, just loop for next h
-				if err != leveldb.ErrNotFound {
-					err = errors.Wrapf(err, "fetch ack in height %d hash %s", h, header.String())
-					return
-				}
-			} else {
-				var dec = &wt.SignedAckHeader{}
-				if err = utils.DecodeMsgPack(v, dec); err != nil {
-					err = errors.Wrapf(err, "fetch ack in height %d hash %s", h, header.String())
-					return
-				}
-				ack = dec
-				break
-			}
-		}
-	}
-	if ack == nil {
-		err = errors.Wrapf(ErrAckQueryNotFound, "fetch ack not found")
-	}
-	return
-}
-
-// syncAckedQuery uses RPC call to synchronize an acknowledged query from a remote node.
-func (c *Chain) syncAckedQuery(height int32, header *hash.Hash, id proto.NodeID) (
-	ack *wt.SignedAckHeader, err error,
-) {
-	req := &MuxFetchAckedQueryReq{
-		Envelope: proto.Envelope{
-			// TODO(leventeliu): Add fields.
-		},
-		DatabaseID: c.rt.databaseID,
-		FetchAckedQueryReq: FetchAckedQueryReq{
-			Height:          height,
-			SignedAckedHash: header,
-		},
-	}
-	resp := &MuxFetchAckedQueryResp{}
-
-	if err = c.cl.CallNode(id, route.SQLCFetchAckedQuery.String(), req, resp); err != nil {
-		log.WithFields(log.Fields{
-			"peer": c.rt.getPeerInfoString(),
-			"time": c.rt.getChainTimeString(),
-		}).WithError(err).Error(
-			"Failed to fetch acked query")
-		return
-	}
-
-	if err = c.VerifyAndPushAckedQuery(resp.Ack); err != nil {
-		return
-	}
-
-	ack = resp.Ack
-	return
-}
-
-// queryOrSyncAckedQuery tries to query an acknowledged query from local index, and also tries to
-// synchronize it from a remote node if not found locally.
-func (c *Chain) queryOrSyncAckedQuery(height int32, header *hash.Hash, id proto.NodeID) (
-	ack *wt.SignedAckHeader, err error,
-) {
-	if ack, err = c.FetchAckedQuery(
-		height, header,
-	); (err == nil && ack != nil) || id == c.rt.getServer() {
-		return
-	}
-	return c.syncAckedQuery(height, header, id)
-}
-
 // CheckAndPushNewBlock implements ChainRPCServer.CheckAndPushNewBlock.
-func (c *Chain) CheckAndPushNewBlock(block *ct.Block) (err error) {
+func (c *Chain) CheckAndPushNewBlock(block *types.Block) (err error) {
 	height := c.rt.getHeightFromTime(block.Timestamp())
 	head := c.rt.getHead()
 	peers := c.rt.getPeers()
@@ -1032,46 +1039,16 @@ func (c *Chain) CheckAndPushNewBlock(block *ct.Block) (err error) {
 	// 	...
 	// }
 
-	// Check queries
-	for _, q := range block.Queries {
-		var ok bool
-
-		if ok, err = c.qi.checkAckFromBlock(height, block.BlockHash(), q); err != nil {
-			return
-		}
-
-		if !ok {
-			if _, err = c.syncAckedQuery(height, q, block.Producer()); err != nil {
-				return
-			}
-
-			if _, err = c.qi.checkAckFromBlock(height, block.BlockHash(), q); err != nil {
-				return
-			}
-		}
-	}
-
-	return c.pushBlock(block)
-}
-
-// VerifyAndPushResponsedQuery verifies a responsed and signed query, and pushed it if valid.
-func (c *Chain) VerifyAndPushResponsedQuery(resp *wt.SignedResponseHeader) (err error) {
-	// TODO(leventeliu): check resp.
-	if c.rt.queryTimeIsExpired(resp.Timestamp) {
-		err = errors.Wrapf(ErrQueryExpired, "Verify response query, min valid height %d, response height %d", c.rt.getMinValidHeight(), c.rt.getHeightFromTime(resp.Timestamp))
-		return
-	}
-
-	if err = resp.Verify(); err != nil {
-		err = errors.Wrapf(err, "")
+	// Replicate local state from the new block
+	if err = c.st.ReplayBlock(block); err != nil {
 		return
 	}
 
-	return c.pushResponedQuery(resp)
+	return c.pushBlock(block)
 }
 
 // VerifyAndPushAckedQuery verifies a acknowledged and signed query, and pushed it if valid.
-func (c *Chain) VerifyAndPushAckedQuery(ack *wt.SignedAckHeader) (err error) {
+func (c *Chain) VerifyAndPushAckedQuery(ack *types.SignedAckHeader) (err error) {
 	// TODO(leventeliu): check ack.
 	if c.rt.queryTimeIsExpired(ack.SignedResponseHeader().Timestamp) {
 		err = errors.Wrapf(ErrQueryExpired, "Verify ack query, min valid height %d, ack height %d", c.rt.getMinValidHeight(), c.rt.getHeightFromTime(ack.Timestamp))
@@ -1101,8 +1078,7 @@ func (c *Chain) getBilling(low, high int32) (req *pt.BillingRequest, err error)
 	var (
 		n                   *blockNode
 		addr                proto.AccountAddress
-		ack                 *wt.SignedAckHeader
-		lowBlock, highBlock *ct.Block
+		lowBlock, highBlock *types.Block
 		billings            = make(map[proto.AccountAddress]*proto.AddrAndGas)
 	)
 
@@ -1114,6 +1090,11 @@ func (c *Chain) getBilling(low, high int32) (req *pt.BillingRequest, err error)
 	}
 
 	for ; n != nil && n.height >= low; n = n.parent {
+		// TODO(leventeliu): block maybe released, use persistence version in this case.
+		if n.block == nil {
+			continue
+		}
+
 		if lowBlock == nil {
 			lowBlock = n.block
 		}
@@ -1135,22 +1116,18 @@ func (c *Chain) getBilling(low, high int32) (req *pt.BillingRequest, err error)
 			}
 		}
 
-		for _, v := range n.block.Queries {
-			if ack, err = c.queryOrSyncAckedQuery(n.height, v, n.block.Producer()); err != nil {
-				return
-			}
-
-			if addr, err = crypto.PubKeyHash(ack.SignedResponseHeader().Signee); err != nil {
+		for _, v := range n.block.Acks {
+			if addr, err = crypto.PubKeyHash(v.SignedResponseHeader().Signee); err != nil {
 				return
 			}
 
 			if billing, ok := billings[addr]; ok {
-				billing.GasAmount += c.rt.price[ack.SignedRequestHeader().QueryType] *
-					ack.SignedRequestHeader().BatchCount
+				billing.GasAmount += c.rt.price[v.SignedRequestHeader().QueryType] *
+					v.SignedRequestHeader().BatchCount
 			} else {
 				billings[addr] = &proto.AddrAndGas{
 					AccountAddress: addr,
-					RawNodeID:      *ack.SignedResponseHeader().NodeID.ToRawNodeID(),
+					RawNodeID:      *v.SignedResponseHeader().NodeID.ToRawNodeID(),
 					GasAmount:      c.rt.producingReward,
 				}
 			}
@@ -1202,7 +1179,7 @@ func (c *Chain) collectBillingSignatures(billings *pt.BillingRequest) {
 	go func() {
 		defer proWG.Done()
 
-		bpReq := &ct.AdviseBillingReq{
+		bpReq := &types.AdviseBillingReq{
 			Req: billings,
 		}
 
@@ -1314,24 +1291,13 @@ func (c *Chain) SignBilling(req *pt.BillingRequest) (
 	if err = req.VerifySignatures(); err != nil {
 		return
 	}
-
 	if loc, err = c.getBilling(req.Header.LowHeight, req.Header.HighHeight); err != nil {
 		return
 	}
-
 	if err = req.Compare(loc); err != nil {
 		return
 	}
-
-	// Sign block with private key
-	priv, err := kms.GetLocalPrivateKey()
-
-	if err != nil {
-		return
-	}
-
-	pub, sig, err = req.SignRequestHeader(priv, false)
-
+	pub, sig, err = req.SignRequestHeader(c.pk, false)
 	return
 }
 
@@ -1414,3 +1380,84 @@ func (c *Chain) replicationCycle() {
 		}
 	}
 }
+
+// Query queries req from local chain state and returns the query results in resp.
+func (c *Chain) Query(req *types.Request) (resp *types.Response, err error) {
+	var ref *x.QueryTracker
+	if ref, resp, err = c.st.Query(req); err != nil {
+		return
+	}
+	if err = resp.Sign(c.pk); err != nil {
+		return
+	}
+	if err = c.addResponse(&resp.Header); err != nil {
+		return
+	}
+	ref.UpdateResp(resp)
+	return
+}
+
+// Replay replays a write log from other peer to replicate storage state.
+func (c *Chain) Replay(req *types.Request, resp *types.Response) (err error) {
+	switch req.Header.QueryType {
+	case types.ReadQuery:
+		return
+	case types.WriteQuery:
+		return c.st.Replay(req, resp)
+	default:
+		err = ErrInvalidRequest
+	}
+	if err = c.addResponse(&resp.Header); err != nil {
+		return
+	}
+	return
+}
+
+func (c *Chain) addResponse(resp *types.SignedResponseHeader) (err error) {
+	return c.ai.addResponse(c.rt.getHeightFromTime(resp.Request.Timestamp), resp)
+}
+
+func (c *Chain) register(ack *types.SignedAckHeader) (err error) {
+	return c.ai.register(c.rt.getHeightFromTime(ack.SignedRequestHeader().Timestamp), ack)
+}
+
+func (c *Chain) remove(ack *types.SignedAckHeader) (err error) {
+	return c.ai.remove(c.rt.getHeightFromTime(ack.SignedRequestHeader().Timestamp), ack)
+}
+
+func (c *Chain) pruneBlockCache() {
+	var (
+		head    = c.rt.getHead().node
+		lastCnt int32
+	)
+	if head == nil {
+		return
+	}
+	lastCnt = head.count - c.rt.blockCacheTTL
+	// Move to last count position
+	for ; head != nil && head.count > lastCnt; head = head.parent {
+	}
+	// Prune block references
+	for ; head != nil && head.block != nil; head = head.parent {
+		head.block = nil
+	}
+}
+
+func (c *Chain) stat() {
+	var (
+		ic = atomic.LoadInt32(&multiIndexCount)
+		rc = atomic.LoadInt32(&responseCount)
+		tc = atomic.LoadInt32(&ackTrackerCount)
+		bc = atomic.LoadInt32(&cachedBlockCount)
+	)
+	// Print chain stats
+	log.WithFields(log.Fields{
+		"database_id":           c.rt.databaseID,
+		"multiIndex_count":      ic,
+		"response_header_count": rc,
+		"query_tracker_count":   tc,
+		"cached_block_count":    bc,
+	}).Info("Chain mem stats")
+	// Print xeno stats
+	c.st.Stat(c.rt.databaseID)
+}
diff --git a/sqlchain/chain_test.go b/sqlchain/chain_test.go
index 42a78df35..798854417 100644
--- a/sqlchain/chain_test.go
+++ b/sqlchain/chain_test.go
@@ -164,15 +164,16 @@ func TestMultiChain(t *testing.T) {
 
 		// Create chain instance
 		config := &Config{
-			DatabaseID: testDatabaseID,
-			DataFile:   dbfile,
-			Genesis:    genesis,
-			Period:     testPeriod,
-			Tick:       testTick,
-			MuxService: mux,
-			Server:     peers.Servers[i],
-			Peers:      peers,
-			QueryTTL:   testQueryTTL,
+			DatabaseID:      testDatabaseID,
+			ChainFilePrefix: dbfile,
+			DataFile:        dbfile,
+			Genesis:         genesis,
+			Period:          testPeriod,
+			Tick:            testTick,
+			MuxService:      mux,
+			Server:          peers.Servers[i],
+			Peers:           peers,
+			QueryTTL:        testQueryTTL,
 		}
 		chain, err := NewChain(config)
 
@@ -307,18 +308,9 @@ func TestMultiChain(t *testing.T) {
 						i, c.rt.getPeerInfoString())
 					continue
 				}
-				t.Logf("Checking block %v at height %d in peer %s",
-					node.block.BlockHash(), i, c.rt.getPeerInfoString())
-				for _, v := range node.block.Queries {
-					if ack, err := c.queryOrSyncAckedQuery(
-						i, v, node.block.Producer(),
-					); err != nil && ack == nil {
-						t.Errorf("Failed to fetch ack %v at height %d in peer %s: %v",
-							v, i, c.rt.getPeerInfoString(), err)
-					} else {
-						t.Logf("Successed to fetch ack %v at height %d in peer %s",
-							v, i, c.rt.getPeerInfoString())
-					}
+				if node.block != nil {
+					t.Logf("Checking block %v at height %d in peer %s",
+						node.block.BlockHash(), i, c.rt.getPeerInfoString())
 				}
 			}
 		}(v.chain)
@@ -355,7 +347,7 @@ func TestMultiChain(t *testing.T) {
 
 						if err != nil {
 							t.Errorf("Error occurred: %v", err)
-						} else if err = c.VerifyAndPushResponsedQuery(resp); err != nil {
+						} else if err = c.addResponse(resp); err != nil {
 							t.Errorf("Error occurred: %v", err)
 						}
 
diff --git a/sqlchain/config.go b/sqlchain/config.go
index 012470bc2..113e99718 100644
--- a/sqlchain/config.go
+++ b/sqlchain/config.go
@@ -19,18 +19,18 @@ package sqlchain
 import (
 	"time"
 
-	"github.com/CovenantSQL/CovenantSQL/blockproducer/types"
+	pt "github.com/CovenantSQL/CovenantSQL/blockproducer/types"
 	"github.com/CovenantSQL/CovenantSQL/proto"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 )
 
 // Config represents a sql-chain config.
 type Config struct {
-	DatabaseID proto.DatabaseID
-	DataFile   string
+	DatabaseID      proto.DatabaseID
+	ChainFilePrefix string
+	DataFile        string
 
-	Genesis *ct.Block
+	Genesis *types.Block
 	Period  time.Duration
 	Tick    time.Duration
 
@@ -39,15 +39,17 @@ type Config struct {
 	Server     proto.NodeID
 
 	// Price sets query price in gases.
-	Price           map[wt.QueryType]uint64
+	Price           map[types.QueryType]uint64
 	ProducingReward uint64
 	BillingPeriods  int32
 
 	// QueryTTL sets the unacknowledged query TTL in block periods.
 	QueryTTL int32
 
+	BlockCacheTTL int32
+
 	// DBAccount info
-	TokenType    types.TokenType
+	TokenType    pt.TokenType
 	GasPrice     uint64
 	UpdatePeriod uint64
 }
diff --git a/sqlchain/errors.go b/sqlchain/errors.go
index 0cbf1c682..10fa9cde8 100644
--- a/sqlchain/errors.go
+++ b/sqlchain/errors.go
@@ -68,7 +68,7 @@ var (
 	// ErrCorruptedIndex indicates that a corrupted index item is detected.
 	ErrCorruptedIndex = errors.New("corrupted index item")
 
-	// ErrUnknownMuxRequest indicates that the a multiplexing request endpoint is not found.
+	// ErrUnknownMuxRequest indicates that the multiplexing request endpoint is not found.
 	ErrUnknownMuxRequest = errors.New("unknown multiplexing request")
 
 	// ErrUnknownProducer indicates that the block has an unknown producer.
@@ -77,8 +77,8 @@ var (
 	// ErrInvalidProducer indicates that the block has an invalid producer.
 	ErrInvalidProducer = errors.New("invalid block producer")
 
-	// ErrUnavailableBillingRang indicates that the billing range is not abailable now.
-	ErrUnavailableBillingRang = errors.New("unabailable billing range")
+	// ErrUnavailableBillingRang indicates that the billing range is not available now.
+	ErrUnavailableBillingRang = errors.New("unavailable billing range")
 
 	// ErrHashNotMatch indicates that a message hash value doesn't match the original hash value
 	// given in its hash field.
@@ -89,4 +89,14 @@ var (
 
 	// ErrAckQueryNotFound indicates that an acknowledged query record is not found.
 	ErrAckQueryNotFound = errors.New("acknowledged query not found")
+
+	// ErrQueryNotFound indicates that a query is not found in the index.
+	ErrQueryNotFound = errors.New("query not found")
+
+	// ErrInvalidRequest indicates the query is invalid.
+	ErrInvalidRequest = errors.New("invalid request")
+
+	// ErrResponseSeqNotMatch indicates that a response sequence id doesn't match the original one
+	// in the index.
+	ErrResponseSeqNotMatch = errors.New("response sequence id doesn't match")
 )
diff --git a/sqlchain/mux.go b/sqlchain/mux.go
index 09a215d81..7dea6dfea 100644
--- a/sqlchain/mux.go
+++ b/sqlchain/mux.go
@@ -75,20 +75,6 @@ type MuxAdviseBinLogResp struct {
 	AdviseBinLogResp
 }
 
-// MuxAdviseResponsedQueryReq defines a request of the AdviseAckedQuery RPC method.
-type MuxAdviseResponsedQueryReq struct {
-	proto.Envelope
-	proto.DatabaseID
-	AdviseResponsedQueryReq
-}
-
-// MuxAdviseResponsedQueryResp defines a response of the AdviseAckedQuery RPC method.
-type MuxAdviseResponsedQueryResp struct {
-	proto.Envelope
-	proto.DatabaseID
-	AdviseResponsedQueryResp
-}
-
 // MuxAdviseAckedQueryReq defines a request of the AdviseAckedQuery RPC method.
 type MuxAdviseAckedQueryReq struct {
 	proto.Envelope
@@ -117,20 +103,6 @@ type MuxFetchBlockResp struct {
 	FetchBlockResp
 }
 
-// MuxFetchAckedQueryReq defines a request of the FetchAckedQuery RPC method.
-type MuxFetchAckedQueryReq struct {
-	proto.Envelope
-	proto.DatabaseID
-	FetchAckedQueryReq
-}
-
-// MuxFetchAckedQueryResp defines a request of the FetchAckedQuery RPC method.
-type MuxFetchAckedQueryResp struct {
-	proto.Envelope
-	proto.DatabaseID
-	FetchAckedQueryResp
-}
-
 // MuxSignBillingReq defines a request of the SignBilling RPC method.
 type MuxSignBillingReq struct {
 	proto.Envelope
@@ -209,19 +181,6 @@ func (s *MuxService) AdviseBinLog(req *MuxAdviseBinLogReq, resp *MuxAdviseBinLog
 	return ErrUnknownMuxRequest
 }
 
-// AdviseResponsedQuery is the RPC method to advise a new responsed query to the target server.
-func (s *MuxService) AdviseResponsedQuery(
-	req *MuxAdviseResponsedQueryReq, resp *MuxAdviseResponsedQueryResp) error {
-	if v, ok := s.serviceMap.Load(req.DatabaseID); ok {
-		resp.Envelope = req.Envelope
-		resp.DatabaseID = req.DatabaseID
-		return v.(*ChainRPCService).AdviseResponsedQuery(
-			&req.AdviseResponsedQueryReq, &resp.AdviseResponsedQueryResp)
-	}
-
-	return ErrUnknownMuxRequest
-}
-
 // AdviseAckedQuery is the RPC method to advise a new acknowledged query to the target server.
 func (s *MuxService) AdviseAckedQuery(
 	req *MuxAdviseAckedQueryReq, resp *MuxAdviseAckedQueryResp) error {
@@ -246,19 +205,6 @@ func (s *MuxService) FetchBlock(req *MuxFetchBlockReq, resp *MuxFetchBlockResp)
 	return ErrUnknownMuxRequest
 }
 
-// FetchAckedQuery is the RPC method to fetch a known block from the target server.
-func (s *MuxService) FetchAckedQuery(
-	req *MuxFetchAckedQueryReq, resp *MuxFetchAckedQueryResp) (err error) {
-	if v, ok := s.serviceMap.Load(req.DatabaseID); ok {
-		resp.Envelope = req.Envelope
-		resp.DatabaseID = req.DatabaseID
-		return v.(*ChainRPCService).FetchAckedQuery(
-			&req.FetchAckedQueryReq, &resp.FetchAckedQueryResp)
-	}
-
-	return ErrUnknownMuxRequest
-}
-
 // SignBilling is the RPC method to get signature for a billing request from the target server.
 func (s *MuxService) SignBilling(req *MuxSignBillingReq, resp *MuxSignBillingResp) (err error) {
 	if v, ok := s.serviceMap.Load(req.DatabaseID); ok {
diff --git a/sqlchain/observer.go b/sqlchain/observer.go
index 8b928427c..e1fa19960 100644
--- a/sqlchain/observer.go
+++ b/sqlchain/observer.go
@@ -21,23 +21,17 @@ import (
 
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 )
 
 /*
-Observer implements interface like a sqlchain including AdviseNewBlock/AdviseAckedQuery.
+Observer implements method AdviseNewBlock to receive blocks from sqlchain node.
 Request/Response entity from sqlchain api is re-used for simplicity.
 
 type Observer interface {
 	AdviseNewBlock(*MuxAdviseNewBlockReq, *MuxAdviseNewBlockResp) error
-	AdviseAckedQuery(*MuxAdviseAckedQueryReq, *MuxAdviseAckedQueryResp) error
 }
-
-The observer could call DBS.GetRequest to fetch original request entity from the DBMS service.
-The whole observation of block producing and write query execution would be as follows.
-AdviseAckedQuery -> AdviseNewBlock -> GetRequest.
 */
 
 // observerReplicator defines observer replication state.
@@ -93,7 +87,7 @@ func (r *observerReplicator) replicate() {
 
 	curHeight := r.c.rt.getHead().Height
 
-	if r.height == ct.ReplicateFromNewest {
+	if r.height == types.ReplicateFromNewest {
 		log.WithFields(log.Fields{
 			"node":   r.nodeID,
 			"height": curHeight,
@@ -121,7 +115,7 @@ func (r *observerReplicator) replicate() {
 	}).Debug("try replicating block for observer")
 
 	// replicate one record
-	var block *ct.Block
+	var block *types.Block
 	if block, err = r.c.FetchBlock(r.height); err != nil {
 		// fetch block failed
 		log.WithField("height", r.height).WithError(err).Warning("fetch block with height failed")
@@ -136,7 +130,7 @@ func (r *observerReplicator) replicate() {
 		// find last available block
 		log.Debug("start block height hole detection")
 
-		var lastBlock, nextBlock *ct.Block
+		var lastBlock, nextBlock *types.Block
 		var lastHeight, nextHeight int32
 
 		for h := r.height - 1; h >= 0; h-- {
@@ -205,36 +199,6 @@ func (r *observerReplicator) replicate() {
 		}).Debug("finish block height hole detection, skipping")
 	}
 
-	// fetch acks in block
-	for _, h := range block.Queries {
-		var ack *wt.SignedAckHeader
-		if ack, err = r.c.queryOrSyncAckedQuery(r.height, h, block.Producer()); err != nil || ack == nil {
-			log.WithFields(log.Fields{
-				"ack":    h.String(),
-				"height": r.height,
-			}).WithError(err).Warning("fetch ack of block height")
-			continue
-		}
-
-		// send advise to this block
-		req := &MuxAdviseAckedQueryReq{
-			Envelope:   proto.Envelope{},
-			DatabaseID: r.c.rt.databaseID,
-			AdviseAckedQueryReq: AdviseAckedQueryReq{
-				Query: ack,
-			},
-		}
-		resp := &MuxAdviseAckedQueryResp{}
-		err = r.c.cl.CallNode(r.nodeID, route.OBSAdviseAckedQuery.String(), req, resp)
-		if err != nil {
-			log.WithFields(log.Fields{
-				"node":   r.nodeID,
-				"height": r.height,
-			}).WithError(err).Warning("send ack advise to observer")
-			return
-		}
-	}
-
 	// send block
 	req := &MuxAdviseNewBlockReq{
 		Envelope:   proto.Envelope{},
diff --git a/sqlchain/otypes/billing_req.go b/sqlchain/otypes/billing_req.go
new file mode 100644
index 000000000..59521a6d4
--- /dev/null
+++ b/sqlchain/otypes/billing_req.go
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package otypes
+
+import (
+	pt "github.com/CovenantSQL/CovenantSQL/blockproducer/types"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+)
+
+// AdviseBillingReq defines a request of the AdviseBillingRequest RPC method.
+type AdviseBillingReq struct {
+	proto.Envelope
+	Req *pt.BillingRequest
+}
+
+// AdviseBillingResp defines a request of the AdviseBillingRequest RPC method.
+type AdviseBillingResp struct {
+	proto.Envelope
+	Resp *pt.BillingRequest
+}
diff --git a/sqlchain/types/block.go b/sqlchain/otypes/block.go
similarity index 81%
rename from sqlchain/types/block.go
rename to sqlchain/otypes/block.go
index 22b10167d..9cf4b8ff0 100644
--- a/sqlchain/types/block.go
+++ b/sqlchain/otypes/block.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"reflect"
@@ -40,24 +40,6 @@ type Header struct {
 	Timestamp   time.Time
 }
 
-//// MarshalHash marshals for hash
-//func (h *Header) MarshalHash() ([]byte, error) {
-//	buffer := bytes.NewBuffer(nil)
-//
-//	if err := utils.WriteElements(buffer, binary.BigEndian,
-//		h.Version,
-//		h.Producer,
-//		&h.GenesisHash,
-//		&h.ParentHash,
-//		&h.MerkleRoot,
-//		h.Timestamp,
-//	); err != nil {
-//		return nil, err
-//	}
-//
-//	return buffer.Bytes(), nil
-//}
-
 // SignedHeader is block header along with its producer signature.
 type SignedHeader struct {
 	Header
@@ -66,27 +48,6 @@ type SignedHeader struct {
 	Signature *asymmetric.Signature
 }
 
-//// MarshalHash marshals for hash.
-//func (s *SignedHeader) MarshalHash() ([]byte, error) {
-//	buffer := bytes.NewBuffer(nil)
-//
-//	if err := utils.WriteElements(buffer, binary.BigEndian,
-//		s.Version,
-//		s.Producer,
-//		&s.GenesisHash,
-//		&s.ParentHash,
-//		&s.MerkleRoot,
-//		s.Timestamp,
-//		&s.BlockHash,
-//		s.Signee,
-//		s.Signature,
-//	); err != nil {
-//		return nil, err
-//	}
-//
-//	return buffer.Bytes(), nil
-//}
-
 // Verify verifies the signature of the signed header.
 func (s *SignedHeader) Verify() error {
 	if !s.Signature.Verify(s.BlockHash[:], s.Signee) {
@@ -142,20 +103,6 @@ func (b *Block) PackAndSignBlock(signer *asymmetric.PrivateKey) (err error) {
 	return
 }
 
-//// MarshalHash marshals for hash
-//func (b *Block) MarshalHash() ([]byte, error) {
-//	buffer := bytes.NewBuffer(nil)
-//
-//	if err := utils.WriteElements(buffer, binary.BigEndian,
-//		&b.SignedHeader,
-//		b.Queries,
-//	); err != nil {
-//		return nil, err
-//	}
-//
-//	return buffer.Bytes(), nil
-//}
-
 // PushAckedQuery pushes a acknowledged and verified query into the block.
 func (b *Block) PushAckedQuery(h *hash.Hash) {
 	if b.Queries == nil {
diff --git a/sqlchain/types/block_gen.go b/sqlchain/otypes/block_gen.go
similarity index 99%
rename from sqlchain/types/block_gen.go
rename to sqlchain/otypes/block_gen.go
index 1d7b3630c..ebd75b2fe 100644
--- a/sqlchain/types/block_gen.go
+++ b/sqlchain/otypes/block_gen.go
@@ -1,4 +1,4 @@
-package types
+package otypes
 
 // Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
 
diff --git a/sqlchain/types/block_gen_test.go b/sqlchain/otypes/block_gen_test.go
similarity index 99%
rename from sqlchain/types/block_gen_test.go
rename to sqlchain/otypes/block_gen_test.go
index 8266f1438..7743f3729 100644
--- a/sqlchain/types/block_gen_test.go
+++ b/sqlchain/otypes/block_gen_test.go
@@ -1,4 +1,4 @@
-package types
+package otypes
 
 // Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
 
diff --git a/sqlchain/types/block_test.go b/sqlchain/otypes/block_test.go
similarity index 99%
rename from sqlchain/types/block_test.go
rename to sqlchain/otypes/block_test.go
index 2a0f74dee..a3dfdb1fe 100644
--- a/sqlchain/types/block_test.go
+++ b/sqlchain/otypes/block_test.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"bytes"
diff --git a/sqlchain/otypes/doc.go b/sqlchain/otypes/doc.go
new file mode 100644
index 000000000..00ef1d7d4
--- /dev/null
+++ b/sqlchain/otypes/doc.go
@@ -0,0 +1,18 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Package otypes defines commonly used types for sql-chain.
+package otypes
diff --git a/sqlchain/types/errors.go b/sqlchain/otypes/errors.go
similarity index 98%
rename from sqlchain/types/errors.go
rename to sqlchain/otypes/errors.go
index 7d856cb81..9a065843d 100644
--- a/sqlchain/types/errors.go
+++ b/sqlchain/otypes/errors.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"errors"
diff --git a/common/types.go b/sqlchain/otypes/observer.go
similarity index 69%
rename from common/types.go
rename to sqlchain/otypes/observer.go
index eebb21745..3eb20dce2 100644
--- a/common/types.go
+++ b/sqlchain/otypes/observer.go
@@ -14,14 +14,11 @@
  * limitations under the License.
  */
 
-package common
+package otypes
 
 const (
-	// AddressLength is the fixed length of a CovenantSQL node address.
-	AddressLength = 64
-	// UUIDLength is the fixed length of a UUID.
-	UUIDLength = 16
+	// ReplicateFromBeginning is the replication offset observes from genesis block.
+	ReplicateFromBeginning = int32(0)
+	// ReplicateFromNewest is the replication offset observes from block head of current node.
+	ReplicateFromNewest = int32(-1)
 )
-
-// UUID is a unique identity which may be used as a Raft transaction ID.
-type UUID [UUIDLength]byte
diff --git a/sqlchain/types/xxx_test.go b/sqlchain/otypes/xxx_test.go
similarity index 99%
rename from sqlchain/types/xxx_test.go
rename to sqlchain/otypes/xxx_test.go
index d6545d79d..428be91c5 100644
--- a/sqlchain/types/xxx_test.go
+++ b/sqlchain/otypes/xxx_test.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"io/ioutil"
diff --git a/sqlchain/queryindex.go b/sqlchain/queryindex.go
deleted file mode 100644
index da30cc84e..000000000
--- a/sqlchain/queryindex.go
+++ /dev/null
@@ -1,574 +0,0 @@
-/*
- * Copyright 2018 The CovenantSQL Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package sqlchain
-
-// TODO(leventeliu): use pooled objects to speed up this index.
-
-import (
-	"sync"
-
-	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
-	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
-	"github.com/pkg/errors"
-)
-
-var (
-	placeHolder = &hash.Hash{}
-)
-
-// requestTracker defines a tracker of a particular database query request.
-// We use it to track and update queries in this index system.
-type requestTracker struct {
-	// TODO(leventeliu): maybe we don't need them to be "signed" here. Given that the response or
-	// Ack is already verified, simply use Header.
-	response *wt.SignedResponseHeader
-	ack      *wt.SignedAckHeader
-	// signedBlock is the hash of the block in the currently best chain which contains this query.
-	signedBlock *hash.Hash
-}
-
-// queryTracker defines a tracker of a particular database query. It may contain multiple queries
-// to differe workers.
-type queryTracker struct {
-	firstAck *requestTracker
-	queries  []*requestTracker
-}
-
-// newQueryTracker returns a new queryTracker reference.
-func newQueryTracker() *queryTracker {
-	return &queryTracker{
-		// TODO(leventeliu): set appropriate capacity.
-		firstAck: nil,
-		queries:  make([]*requestTracker, 0, 10),
-	}
-}
-
-// updateAck updates the query tracker with a verified SignedAckHeader.
-func (s *requestTracker) updateAck(ack *wt.SignedAckHeader) (isNew bool, err error) {
-	if s.ack == nil {
-		// A later Ack can overwrite the original Response setting
-		*s = requestTracker{
-			response: ack.SignedResponseHeader(),
-			ack:      ack,
-		}
-
-		isNew = true
-	} else if !s.ack.Hash.IsEqual(&ack.Hash) {
-		// This may happen when a client sends multiple acknowledgements for a same query (same
-		// response header hash)
-		err = ErrMultipleAckOfResponse
-	} // else it's same as s.Ack, let's try not to overwrite it
-
-	return
-}
-
-// hashIndex defines a requestTracker index using hash as key.
-type hashIndex map[hash.Hash]*requestTracker
-
-// seqIndex defines a queryTracker index using sequence number as key.
-type seqIndex map[wt.QueryKey]*queryTracker
-
-// ensure returns the *queryTracker associated with the given key. It creates a new item if the
-// key doesn't exist.
-func (i seqIndex) ensure(k wt.QueryKey) (v *queryTracker) {
-	var ok bool
-
-	if v, ok = i[k]; !ok {
-		v = newQueryTracker()
-		i[k] = v
-	}
-
-	return
-}
-
-// multiIndex defines a combination of multiple indexes.
-//
-// Index layout is as following:
-//
-//  respIndex                                    +----------------+
-//                +---------------------------+->| requestTracker |       +---------------------------+
-// |  ...   |     |                           |  | +-response     |------>| signedresponseheader      |
-// +--------+     |                           |  | +-ack (nil)    |       | +-ResponseHeader          |
-// | hash#1 |-----+                           |  | +-...          |       | | +-SignedRequestHeader   |
-// +--------+                                 |  +----------------+       | | | +-RequestHeader       |
-// |  ...   |                                 |                           | | | | +-...               |
-// +--------+           +------------------+  |                           | | | | +-SeqNo: seq#0      |
-// | hash#3 |-----+  +->| queryTracker     |  |                           | | | | +-...               |
-// +--------+     |  |  | +-firstAck (nil) |  |                           | | | +-Hash = hash#0 |
-// |  ...   |     |  |  | +-queries        |  |                           | | | +-Signee ====> pubk#0 |
-// +--------+     |  |  |   +-[0]          |--+                           | | | +-Signature => sign#0 |
-// | hash#6 |--+  |  |  |   +-...          |                              | | +-...                   |
-// +--------+  |  |  |  +------------------+                              | +-Hash = hash#1     |
-// |  ...   |  |  |  |                                                    | +-Signee ====> pubk#1     |
-//             |  |  |                                                    | +-Signature => sign#1     |
-//             |  |  |                                                    +---------------------------+
-//             |  |  |                           +----------------+
-//             |  +-------------+---------+-+--->| requestTracker |
-//             |     |          |         | |    | +-response     |----+  +-------------------------------+
-//  ackindex   |     |          |         | |    | +-ack          |----|->| SignedAckHeader               |
-//             |     |          |         | |    | +-...          |    |  | +-AckHeader                   |
-// |  ...   |  |     |          |         | |    +----------------+    +->| | +-SignedResponseHeader      |
-// +--------+  |     |          |         | |                             | | | +-ResponseHeader          |
-// | hash#4 |--|----------------+         | |                             | | | | +-SignedRequestHeader   |
-// +--------+  |     |                    | |                             | | | | | +-RequestHeader       |
-// |  ...   |  |     |                    | |                             | | | | | | +-...               |
-//             |     |                    | |                             | | | | | | +-SeqNo: seq#1      |
-//             |     |                    | |                             | | | | | | +-...               |
-//             |     |                    | |                             | | | | | +-Hash = hash#2 |
-//             |     |                    | |                             | | | | | +-Signee ====> pubk#2 |
-//             |     |                    | |                             | | | | | +-Signature => sign#2 |
-//  seqIndex   |     |                    | |    +----------------+       | | | | +-...                   |
-//             +------------------------------+->| requestTracker |       | | | +-Hash = hash#3     |
-// |  ...   |        |                    | | |  | +-response     |---+   | | | +-signee ====> pubk#3     |
-// +--------+        |                    | | |  | +-ack (nil)    |   |   | | | +-Signature => sign#3     |
-// | seq#0  |--------+                    | | |  | +-...          |   |   | | +-...                       |
-// +--------+                             | | |  +----------------+   |   | +-Hash = hash#4         |
-// |  ...   |                             | | |                       |   | +-Signee ====> pubk#2         |
-// +--------+           +--------------+  | | |                       |   | +-Signature => sign#4         |
-// | seq#1  |---------->| queryTracker |  | | |                       |   +-------------------------------+
-// +--------+           | +-firstAck   |--+ | |                       |
-// |  ...   |           | +-queries    |    | |                       |
-//                      |   +-[0]      |----+ |                       |
-//                      |   +-[1]      |------+                       |   +---------------------------+
-//                      |   +-...      |                              +-->| SignedResponseHeader      |
-//                      +--------------+                                  | +-ResponseHeader          |
-//                                                                        | | +-SignedRequestHeader   |
-//                                                                        | | | +-RequestHeader       |
-//                                                                        | | | | +-...               |
-//                                                                        | | | | +-SeqNo: seq#1      |
-//                                                                        | | | | +-...               |
-//                                                                        | | | +-Hash = hash#5 |
-//                                                                        | | | +-Signee ====> pubk#5 |
-//                                                                        | | | +-Signature => sign#5 |
-//                                                                        | | +-...                   |
-//                                                                        | +-Hash = hash#6     |
-//                                                                        | +-Signee ====> pubk#6     |
-//                                                                        | +-Signature => sign#6     |
-//                                                                        +---------------------------+
-//
-type multiIndex struct {
-	sync.Mutex
-	respIndex, ackIndex hashIndex
-	seqIndex
-}
-
-// newMultiIndex returns a new multiIndex reference.
-func newMultiIndex() *multiIndex {
-	return &multiIndex{
-		respIndex: make(map[hash.Hash]*requestTracker),
-		ackIndex:  make(map[hash.Hash]*requestTracker),
-		seqIndex:  make(map[wt.QueryKey]*queryTracker),
-	}
-}
-
-// addResponse adds the responsed query to the index.
-func (i *multiIndex) addResponse(resp *wt.SignedResponseHeader) (err error) {
-	i.Lock()
-	defer i.Unlock()
-
-	if v, ok := i.respIndex[resp.Hash]; ok {
-		if v == nil || v.response == nil {
-			// TODO(leventeliu): consider to panic.
-			err = ErrCorruptedIndex
-			return
-		}
-
-		// Given that `resp` is already verified by user, its header should be deeply equal to
-		// v.response.ResponseHeader.
-		// Considering that we may allow a node to update its key pair on-the-fly, just overwrite
-		// this response.
-		v.response = resp
-		return
-	}
-
-	// Create new item
-	s := &requestTracker{
-		response: resp,
-	}
-
-	i.respIndex[resp.Hash] = s
-	q := i.seqIndex.ensure(resp.Request.GetQueryKey())
-	q.queries = append(q.queries, s)
-
-	return nil
-}
-
-// addAck adds the acknowledged query to the index.
-func (i *multiIndex) addAck(ack *wt.SignedAckHeader) (err error) {
-	i.Lock()
-	defer i.Unlock()
-	var v *requestTracker
-	var ok bool
-	q := i.seqIndex.ensure(ack.SignedRequestHeader().GetQueryKey())
-
-	if v, ok = i.respIndex[ack.ResponseHash()]; ok {
-		if v == nil || v.response == nil {
-			// TODO(leventeliu): consider to panic.
-			err = ErrCorruptedIndex
-			return
-		}
-
-		// Add hash -> ack index anyway, so that we can find the request tracker later, even if
-		// there is a earlier acknowledgement for the same request
-		i.ackIndex[ack.Hash] = v
-
-		// This also updates the item indexed by ackIndex and seqIndex
-		var isNew bool
-
-		if isNew, err = v.updateAck(ack); err != nil {
-			return
-		}
-
-		if isNew {
-			q.queries = append(q.queries, v)
-		}
-	} else {
-		// Build new queryTracker and update both indexes
-		v = &requestTracker{
-			response: ack.SignedResponseHeader(),
-			ack:      ack,
-		}
-
-		i.respIndex[ack.ResponseHash()] = v
-		i.ackIndex[ack.Hash] = v
-		q.queries = append(q.queries, v)
-	}
-
-	// TODO(leventeliu):
-	// This query has multiple signed acknowledgements. It may be caused by a network problem.
-	// We will keep the first ack counted anyway. But, should we report it to someone?
-	if q.firstAck == nil {
-		q.firstAck = v
-	} else if !q.firstAck.ack.Hash.IsEqual(&ack.Hash) {
-		err = ErrMultipleAckOfSeqNo
-	}
-
-	return
-}
-
-func (i *multiIndex) getAck(header *hash.Hash) (ack *wt.SignedAckHeader, ok bool) {
-	i.Lock()
-	defer i.Unlock()
-
-	var t *requestTracker
-	if t, ok = i.ackIndex[*header]; ok {
-		ack = t.ack
-	}
-
-	return
-}
-
-// setSignedBlock sets the signed block of the acknowledged query.
-func (i *multiIndex) setSignedBlock(blockHash *hash.Hash, ackHeaderHash *hash.Hash) {
-	i.Lock()
-	defer i.Unlock()
-
-	if v, ok := i.ackIndex[*ackHeaderHash]; ok {
-		v.signedBlock = blockHash
-	}
-}
-
-//  resetSignedBlock resets the signed block of the acknowledged query.
-func (i *multiIndex) resetSignedBlock(blockHash *hash.Hash, ackHeaderHash *hash.Hash) {
-	i.Lock()
-	defer i.Unlock()
-
-	if v, ok := i.ackIndex[*ackHeaderHash]; ok {
-		// TODO(leventeliu): check if v.signedBlock equals blockHash.
-		v.signedBlock = nil
-	}
-}
-
-// checkBeforeExpire checks the index and does some necessary work before it expires.
-func (i *multiIndex) checkBeforeExpire() {
-	i.Lock()
-	defer i.Unlock()
-
-	for _, q := range i.seqIndex {
-		if ack := q.firstAck; ack == nil {
-			// TODO(leventeliu):
-			// This query is not acknowledged and expires now.
-		} else if ack.signedBlock == nil || ack.signedBlock == placeHolder {
-			// TODO(leventeliu):
-			// This query was acknowledged normally but collectors didn't pack it in any block.
-			// There is definitely something wrong with them.
-		}
-
-		for _, s := range q.queries {
-			if s != q.firstAck {
-				// TODO(leventeliu): so these guys lost the competition in this query. Should we
-				// do something about it?
-			}
-		}
-	}
-}
-
-// checkAckFromBlock checks a acknowledged query from a block in this index.
-func (i *multiIndex) checkAckFromBlock(b *hash.Hash, ack *hash.Hash) (isKnown bool, err error) {
-	i.Lock()
-	defer i.Unlock()
-
-	// Check acknowledgement
-	q, isKnown := i.ackIndex[*ack]
-
-	if !isKnown {
-		return
-	}
-
-	if q.signedBlock != nil && !q.signedBlock.IsEqual(b) {
-		err = ErrQuerySignedByAnotherBlock
-		log.WithFields(log.Fields{
-			"query":        ack.String(),
-			"block":        b.String(),
-			"signed_block": q.signedBlock.String(),
-		}).WithError(err).Error(
-			"Failed to check acknowledgement from block")
-		return
-	}
-
-	qs := i.seqIndex[q.ack.SignedRequestHeader().GetQueryKey()]
-
-	// Check it as a first acknowledgement
-	if i.respIndex[q.response.Hash] != q || qs == nil || qs.firstAck == nil {
-		err = ErrCorruptedIndex
-		return
-	}
-
-	// If `q` is not considered first acknowledgement of this query locally
-	if qs.firstAck != q {
-		if qs.firstAck.signedBlock != nil {
-			err = ErrQuerySignedByAnotherBlock
-			log.WithFields(log.Fields{
-				"query": ack.String(),
-				"block": b.String(),
-				"signed_block": func() string {
-					if q.signedBlock != nil {
-						return q.signedBlock.String()
-					}
-					return "nil"
-				}(),
-			}).WithError(err).Error(
-				"Failed to check acknowledgement from block")
-			return
-		}
-
-		// But if the acknowledgement is not signed yet, it is also acceptable to promote another
-		// acknowledgement
-		qs.firstAck = q
-	}
-
-	return
-}
-
-// markAndCollectUnsignedAcks marks and collects all the unsigned acknowledgements in the index.
-func (i *multiIndex) markAndCollectUnsignedAcks(qs *[]*hash.Hash) {
-	i.Lock()
-	defer i.Unlock()
-
-	for _, q := range i.seqIndex {
-		if ack := q.firstAck; ack != nil && ack.signedBlock == nil {
-			ack.signedBlock = placeHolder
-			*qs = append(*qs, &ack.ack.Hash)
-		}
-	}
-}
-
-// heightIndex defines a MultiIndex index using height as key.
-type heightIndex struct {
-	sync.Mutex
-	index map[int32]*multiIndex
-}
-
-// ensureHeight returns the *MultiIndex associated with the given height. It creates a new item if
-// the key doesn't exist.
-func (i *heightIndex) ensureHeight(h int32) (v *multiIndex) {
-	i.Lock()
-	defer i.Unlock()
-	v, ok := i.index[h]
-
-	if !ok {
-		v = newMultiIndex()
-		i.index[h] = v
-	}
-
-	return
-}
-
-// ensureRange creates new *multiIndex items associated within the given height range [l, h) for
-// those don't exist.
-func (i *heightIndex) ensureRange(l, h int32) {
-	i.Lock()
-	defer i.Unlock()
-
-	for x := l; x < h; x++ {
-		if _, ok := i.index[x]; !ok {
-			i.index[x] = newMultiIndex()
-		}
-	}
-}
-
-func (i *heightIndex) get(k int32) (v *multiIndex, ok bool) {
-	i.Lock()
-	defer i.Unlock()
-	v, ok = i.index[k]
-	return
-}
-
-func (i *heightIndex) del(k int32) {
-	i.Lock()
-	defer i.Unlock()
-	delete(i.index, k)
-}
-
-// queryIndex defines a query index maintainer.
-type queryIndex struct {
-	heightIndex *heightIndex
-
-	sync.Mutex
-	barrier int32
-}
-
-func (i *queryIndex) getBarrier() int32 {
-	i.Lock()
-	defer i.Unlock()
-	return i.barrier
-}
-
-func (i *queryIndex) setBarrier(b int32) {
-	i.Lock()
-	defer i.Unlock()
-	i.barrier = b
-}
-
-// newQueryIndex returns a new queryIndex reference.
-func newQueryIndex() *queryIndex {
-	return &queryIndex{
-		heightIndex: &heightIndex{
-			index: make(map[int32]*multiIndex),
-		},
-	}
-}
-
-// addResponse adds the responsed query to the index.
-func (i *queryIndex) addResponse(h int32, resp *wt.SignedResponseHeader) error {
-	// TODO(leventeliu): we should ensure that the Request uses coordinated timestamp, instead of
-	// any client local time.
-	return i.heightIndex.ensureHeight(h).addResponse(resp)
-}
-
-// addAck adds the acknowledged query to the index.
-func (i *queryIndex) addAck(h int32, ack *wt.SignedAckHeader) error {
-	return i.heightIndex.ensureHeight(h).addAck(ack)
-}
-
-// checkAckFromBlock checks a acknowledged query from a block at the given height.
-func (i *queryIndex) checkAckFromBlock(h int32, b *hash.Hash, ack *hash.Hash) (
-	isKnown bool, err error) {
-	l := i.getBarrier()
-
-	if h < l {
-		err = errors.Wrapf(ErrQueryExpired, "check Ack, height %d, barrier %d", h, l)
-		return
-	}
-
-	for x := l; x <= h; x++ {
-		if hi, ok := i.heightIndex.get(x); ok {
-			if isKnown, err = hi.checkAckFromBlock(b, ack); err != nil || isKnown {
-				return
-			}
-		}
-	}
-
-	return
-}
-
-// setSignedBlock updates the signed block in index for the acknowledged queries in the block.
-func (i *queryIndex) setSignedBlock(h int32, block *ct.Block) {
-	b := i.getBarrier()
-
-	for _, v := range block.Queries {
-		for x := b; x <= h; x++ {
-			if hi, ok := i.heightIndex.get(x); ok {
-				hi.setSignedBlock(block.BlockHash(), v)
-			}
-		}
-	}
-}
-
-func (i *queryIndex) resetSignedBlock(h int32, block *ct.Block) {
-	b := i.getBarrier()
-
-	for _, v := range block.Queries {
-		for x := b; x <= h; x++ {
-			if hi, ok := i.heightIndex.get(x); ok {
-				hi.resetSignedBlock(block.BlockHash(), v)
-			}
-		}
-	}
-}
-
-// getAck gets the acknowledged queries from the index.
-func (i *queryIndex) getAck(h int32, header *hash.Hash) (ack *wt.SignedAckHeader, err error) {
-	b := i.getBarrier()
-
-	if h < b {
-		err = errors.Wrapf(ErrQueryExpired, "get Ack, height %d, barrier %d", h, b)
-		return
-	}
-
-	for x := b; x <= h; x++ {
-		if hi, ok := i.heightIndex.get(x); ok {
-			if ack, ok = hi.getAck(header); ok {
-				return
-			}
-		}
-	}
-
-	err = ErrQueryNotCached
-	return
-}
-
-// advanceBarrier moves barrier to given height. All buckets lower than this height will be set as
-// expired, and all the queries which are not packed in these buckets will be reported.
-func (i *queryIndex) advanceBarrier(height int32) {
-	b := i.getBarrier()
-	i.setBarrier(height)
-
-	for x := b; x < height; x++ {
-		if hi, ok := i.heightIndex.get(x); ok {
-			hi.checkBeforeExpire()
-			i.heightIndex.del(x)
-		}
-	}
-}
-
-// markAndCollectUnsignedAcks marks and collects all the unsigned acknowledgements which can be
-// signed by a block at the given height.
-func (i *queryIndex) markAndCollectUnsignedAcks(height int32) (qs []*hash.Hash) {
-	b := i.getBarrier()
-	qs = make([]*hash.Hash, 0, 1024)
-
-	for x := b; x < height; x++ {
-		if hi, ok := i.heightIndex.get(x); ok {
-			hi.markAndCollectUnsignedAcks(&qs)
-		}
-	}
-
-	return
-}
diff --git a/sqlchain/queryindex_test.go b/sqlchain/queryindex_test.go
deleted file mode 100644
index 01bb5bc13..000000000
--- a/sqlchain/queryindex_test.go
+++ /dev/null
@@ -1,394 +0,0 @@
-/*
- * Copyright 2018 The CovenantSQL Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package sqlchain
-
-import (
-	"math/rand"
-	"reflect"
-	"testing"
-
-	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
-	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	"github.com/pkg/errors"
-)
-
-const (
-	testBucketNumber         = 10
-	testQueryNumberPerHeight = 10
-	testClientNumber         = 10
-	testWorkerNumber         = 10
-	testQueryWorkerNumber    = 3
-)
-
-func (i *heightIndex) mustGet(k int32) *multiIndex {
-	i.Lock()
-	defer i.Unlock()
-	return i.index[k]
-}
-
-func TestCorruptedIndex(t *testing.T) {
-	ack, err := createRandomNodesAndAck()
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	resp := ack.SignedResponseHeader()
-
-	// Create index
-	qi := newQueryIndex()
-
-	if err = qi.addResponse(0, resp); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	if err = qi.addAck(0, ack); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	// Test repeatedly add
-	if err = qi.addResponse(0, resp); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	if err = qi.addAck(0, ack); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	// Test corrupted index
-	qi.heightIndex.mustGet(0).respIndex[resp.Hash].response = nil
-
-	if err = qi.addResponse(0, resp); err != ErrCorruptedIndex {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-
-	if err = qi.addAck(0, ack); err != ErrCorruptedIndex {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-
-	qi.heightIndex.mustGet(0).respIndex[resp.Hash] = nil
-
-	if err = qi.addResponse(0, resp); err != ErrCorruptedIndex {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-
-	if err = qi.addAck(0, ack); err != ErrCorruptedIndex {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-}
-
-func TestSingleAck(t *testing.T) {
-	ack, err := createRandomNodesAndAck()
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	qi := newQueryIndex()
-
-	if err = qi.addAck(0, ack); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	// Check not signed ack
-	qi.heightIndex.mustGet(0).checkBeforeExpire()
-}
-
-func TestEnsureRange(t *testing.T) {
-	qi := newQueryIndex()
-	qi.heightIndex.ensureRange(0, 10)
-
-	for i := 0; i < 10; i++ {
-		if _, ok := qi.heightIndex.get(int32(i)); !ok {
-			t.Fatalf("Failed to ensure height %d", i)
-		}
-	}
-}
-
-func TestCheckAckFromBlock(t *testing.T) {
-	var height int32 = 10
-	qi := newQueryIndex()
-	qi.advanceBarrier(height)
-	b1, err := createRandomBlock(genesisHash, false)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	if _, err := qi.checkAckFromBlock(
-		0, b1.BlockHash(), b1.Queries[0],
-	); errors.Cause(err) != ErrQueryExpired {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-
-	if isKnown, err := qi.checkAckFromBlock(
-		height, b1.BlockHash(), b1.Queries[0],
-	); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	} else if isKnown {
-		t.Fatal("Unexpected result: index should not know this query")
-	}
-
-	// Create a group of query for test
-	cli, err := newRandomNode()
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	worker1, err := newRandomNode()
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	worker2, err := newRandomNode()
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	req, err := createRandomQueryRequest(cli)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	resp1, err := createRandomQueryResponseWithRequest(req, worker1)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	ack1, err := createRandomQueryAckWithResponse(resp1, cli)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	resp2, err := createRandomQueryResponseWithRequest(req, worker2)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	ack2, err := createRandomQueryAckWithResponse(resp2, cli)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	// Test a query signed by another block
-	if err = qi.addAck(height, ack1); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	if err = qi.addAck(height, ack2); err != ErrMultipleAckOfSeqNo {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-
-	b2, err := createRandomBlock(genesisHash, false)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	b1.Queries[0] = &ack1.Hash
-	b2.Queries[0] = &ack1.Hash
-	qi.setSignedBlock(height, b1)
-
-	if _, err := qi.checkAckFromBlock(
-		height, b2.BlockHash(), b2.Queries[0],
-	); err != ErrQuerySignedByAnotherBlock {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-
-	// Test checking same ack signed by another block
-	b2.Queries[0] = &ack2.Hash
-
-	if _, err = qi.checkAckFromBlock(
-		height, b2.BlockHash(), b2.Queries[0],
-	); err != ErrQuerySignedByAnotherBlock {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-
-	// Revert index state for the first block, and test checking again
-	qi.heightIndex.mustGet(height).seqIndex[req.GetQueryKey()].firstAck.signedBlock = nil
-
-	if _, err = qi.checkAckFromBlock(
-		height, b2.BlockHash(), b2.Queries[0],
-	); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	// Test corrupted index
-	qi.heightIndex.mustGet(height).seqIndex[req.GetQueryKey()] = nil
-
-	if _, err = qi.checkAckFromBlock(
-		height, b2.BlockHash(), b2.Queries[0],
-	); err != ErrCorruptedIndex {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-}
-
-func TestGetAck(t *testing.T) {
-	qi := newQueryIndex()
-	qh := &hash.Hash{}
-
-	if _, err := qi.getAck(-1, qh); errors.Cause(err) != ErrQueryExpired {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-
-	if _, err := qi.getAck(0, qh); errors.Cause(err) != ErrQueryNotCached {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-}
-
-func TestQueryIndex(t *testing.T) {
-	log.SetLevel(log.InfoLevel)
-	// Initialize clients and workers
-	clients, err := newRandomNodes(testClientNumber)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	workers, err := newRandomNodes(testWorkerNumber)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	// Initialize index
-	qi := newQueryIndex()
-
-	// Create some responses and acknowledgements and insert to index
-	for i := 0; i < testBucketNumber; i++ {
-		qi.advanceBarrier(int32(i))
-		block, err := createRandomBlock(genesisHash, false)
-
-		if err != nil {
-			t.Fatalf("Error occurred: %v", err)
-		}
-
-		block.Queries = block.Queries[:0]
-
-		for j := 0; j < testQueryNumberPerHeight; j++ {
-			cli := clients[rand.Intn(testClientNumber)]
-			req, err := createRandomQueryRequest(cli)
-			hasFirstAck := false
-
-			if err != nil {
-				t.Fatalf("Error occurred: %v", err)
-			}
-
-			ackNumber := rand.Intn(testQueryWorkerNumber + 1)
-
-			for k := 0; k < testQueryWorkerNumber; k++ {
-				worker := workers[(rand.Intn(testWorkerNumber)+k)%testWorkerNumber]
-				resp, err := createRandomQueryResponseWithRequest(req, worker)
-
-				if err != nil {
-					t.Fatalf("Error occurred: %v", err)
-				}
-
-				log.Debugf("i = %d, j = %d, k = %d\n\tseqno = %+v, req = %v, resp = %v", i, j, k,
-					resp.Request.GetQueryKey(), &req.Hash, &resp.Hash)
-
-				if err = qi.addResponse(int32(i), resp); err != nil {
-					t.Fatalf("Error occurred: %v", err)
-				}
-
-				if k < ackNumber {
-					dupAckNumber := 1 + rand.Intn(2)
-
-					for l := 0; l < dupAckNumber; l++ {
-						ack, err := createRandomQueryAckWithResponse(resp, cli)
-
-						log.Debugf("i = %d, j = %d, k = %d, l = %d\n\tseqno = %+v, "+
-							"req = %v, resp = %v, ack = %v",
-							i, j, k, l,
-							ack.SignedRequestHeader().GetQueryKey(),
-							&ack.SignedRequestHeader().Hash,
-							&ack.SignedResponseHeader().Hash,
-							&ack.Hash,
-						)
-
-						if err != nil {
-							t.Fatalf("Error occurred: %v", err)
-						}
-
-						err = qi.addAck(int32(i), ack)
-
-						if !hasFirstAck {
-							if l == 0 && err != nil ||
-								l > 0 && err != nil && err != ErrMultipleAckOfResponse {
-								t.Fatalf("Error occurred: %v", err)
-							}
-						} else {
-							if l == 0 && err == nil {
-								t.Fatalf("Unexpected error: %v", err)
-							}
-						}
-
-						if err == nil {
-							hasFirstAck = true
-							block.PushAckedQuery(&ack.Hash)
-						} else {
-							continue
-						}
-
-						if rAck, err := qi.getAck(int32(i), &ack.Hash); err != nil {
-							t.Fatalf("Error occurred: %v", err)
-						} else if !reflect.DeepEqual(ack, rAck) {
-							t.Fatalf("Unexpected result:\n\torigin = %+v\n\toutput = %+v",
-								ack, rAck)
-						} else if !reflect.DeepEqual(
-							ack.SignedResponseHeader(), rAck.SignedResponseHeader()) {
-							t.Fatalf("Unexpected result:\n\torigin = %+v\n\toutput = %+v",
-								ack.SignedResponseHeader(), rAck.SignedResponseHeader())
-						}
-					}
-				}
-			}
-
-			qi.setSignedBlock(int32(i), block)
-
-			for j := range block.Queries {
-				if isKnown, err := qi.checkAckFromBlock(
-					int32(i), block.BlockHash(), block.Queries[j],
-				); err != nil {
-					t.Fatalf("Error occurred: %v", err)
-				} else if !isKnown {
-					t.Logf("Failed to check known ack: %s", block.Queries[j])
-				}
-			}
-
-			qi.resetSignedBlock(int32(i), block)
-
-			for j := range block.Queries {
-				if isKnown, err := qi.checkAckFromBlock(
-					int32(i), block.BlockHash(), block.Queries[j],
-				); err != nil {
-					t.Fatalf("Error occurred: %v", err)
-				} else if !isKnown {
-					t.Fatal("Unexpected result: block is known")
-				}
-			}
-		}
-	}
-}
diff --git a/sqlchain/rpc.go b/sqlchain/rpc.go
index 5bb7fcbdf..5ed518267 100644
--- a/sqlchain/rpc.go
+++ b/sqlchain/rpc.go
@@ -21,8 +21,7 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
 	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
 	"github.com/CovenantSQL/CovenantSQL/proto"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 )
 
 // ChainRPCService defines a sql-chain RPC server.
@@ -32,7 +31,7 @@ type ChainRPCService struct {
 
 // AdviseNewBlockReq defines a request of the AdviseNewBlock RPC method.
 type AdviseNewBlockReq struct {
-	Block *ct.Block
+	Block *types.Block
 	Count int32
 }
 
@@ -48,18 +47,9 @@ type AdviseBinLogReq struct {
 type AdviseBinLogResp struct {
 }
 
-// AdviseResponsedQueryReq defines a request of the AdviseAckedQuery RPC method.
-type AdviseResponsedQueryReq struct {
-	Query *wt.SignedResponseHeader
-}
-
-// AdviseResponsedQueryResp defines a response of the AdviseAckedQuery RPC method.
-type AdviseResponsedQueryResp struct {
-}
-
 // AdviseAckedQueryReq defines a request of the AdviseAckedQuery RPC method.
 type AdviseAckedQueryReq struct {
-	Query *wt.SignedAckHeader
+	Query *types.SignedAckHeader
 }
 
 // AdviseAckedQueryResp defines a response of the AdviseAckedQuery RPC method.
@@ -74,18 +64,7 @@ type FetchBlockReq struct {
 // FetchBlockResp defines a response of the FetchBlock RPC method.
 type FetchBlockResp struct {
 	Height int32
-	Block  *ct.Block
-}
-
-// FetchAckedQueryReq defines a request of the FetchAckedQuery RPC method.
-type FetchAckedQueryReq struct {
-	Height          int32
-	SignedAckedHash *hash.Hash
-}
-
-// FetchAckedQueryResp defines a request of the FetchAckedQuery RPC method.
-type FetchAckedQueryResp struct {
-	Ack *wt.SignedAckHeader
+	Block  *types.Block
 }
 
 // SignBillingReq defines a request of the SignBilling RPC method.
@@ -140,12 +119,6 @@ func (s *ChainRPCService) AdviseBinLog(req *AdviseBinLogReq, resp *AdviseBinLogR
 	return nil
 }
 
-// AdviseResponsedQuery is the RPC method to advise a new responsed query to the target server.
-func (s *ChainRPCService) AdviseResponsedQuery(
-	req *AdviseResponsedQueryReq, resp *AdviseResponsedQueryResp) error {
-	return s.chain.VerifyAndPushResponsedQuery(req.Query)
-}
-
 // AdviseAckedQuery is the RPC method to advise a new acknowledged query to the target server.
 func (s *ChainRPCService) AdviseAckedQuery(
 	req *AdviseAckedQueryReq, resp *AdviseAckedQueryResp) error {
@@ -159,13 +132,6 @@ func (s *ChainRPCService) FetchBlock(req *FetchBlockReq, resp *FetchBlockResp) (
 	return
 }
 
-// FetchAckedQuery is the RPC method to fetch a known block from the target server.
-func (s *ChainRPCService) FetchAckedQuery(req *FetchAckedQueryReq, resp *FetchAckedQueryResp,
-) (err error) {
-	resp.Ack, err = s.chain.FetchAckedQuery(req.Height, req.SignedAckedHash)
-	return
-}
-
 // SignBilling is the RPC method to get signature for a billing request from the target server.
 func (s *ChainRPCService) SignBilling(req *SignBillingReq, resp *SignBillingResp) (err error) {
 	resp.HeaderHash = req.BillingRequest.RequestHash
diff --git a/sqlchain/runtime.go b/sqlchain/runtime.go
index e3754024d..b1935558d 100644
--- a/sqlchain/runtime.go
+++ b/sqlchain/runtime.go
@@ -23,9 +23,8 @@ import (
 
 	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
 	"github.com/CovenantSQL/CovenantSQL/proto"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 )
 
 // runtime represents a chain runtime state.
@@ -48,10 +47,12 @@ type runtime struct {
 	tick time.Duration
 	// queryTTL sets the unacknowledged query TTL in block periods.
 	queryTTL int32
+	// blockCacheTTL sets the cached block numbers.
+	blockCacheTTL int32
 	// muxServer is the multiplexing service of sql-chain PRC.
 	muxService *MuxService
 	// price sets query price in gases.
-	price           map[wt.QueryType]uint64
+	price           map[types.QueryType]uint64
 	producingReward uint64
 	billingPeriods  int32
 
@@ -86,11 +87,17 @@ type runtime struct {
 // newRunTime returns a new sql-chain runtime instance with the specified config.
 func newRunTime(c *Config) (r *runtime) {
 	r = &runtime{
-		stopCh:          make(chan struct{}),
-		databaseID:      c.DatabaseID,
-		period:          c.Period,
-		tick:            c.Tick,
-		queryTTL:        c.QueryTTL,
+		stopCh:     make(chan struct{}),
+		databaseID: c.DatabaseID,
+		period:     c.Period,
+		tick:       c.Tick,
+		queryTTL:   c.QueryTTL,
+		blockCacheTTL: func() int32 {
+			if c.BlockCacheTTL < minBlockCacheTTL {
+				return minBlockCacheTTL
+			}
+			return c.BlockCacheTTL
+		}(),
 		muxService:      c.MuxService,
 		price:           c.Price,
 		producingReward: c.ProducingReward,
@@ -122,7 +129,7 @@ func newRunTime(c *Config) (r *runtime) {
 	return
 }
 
-func (r *runtime) setGenesis(b *ct.Block) {
+func (r *runtime) setGenesis(b *types.Block) {
 	r.chainInitTime = b.Timestamp()
 	r.genesisHash = *b.BlockHash()
 	r.head = &state{
@@ -190,7 +197,7 @@ func (r *runtime) setNextTurn() {
 }
 
 // getQueryGas gets the consumption of gas for a specified query type.
-func (r *runtime) getQueryGas(t wt.QueryType) uint64 {
+func (r *runtime) getQueryGas(t types.QueryType) uint64 {
 	return r.price[t]
 }
 
diff --git a/sqlchain/storage/storage.go b/sqlchain/storage/storage.go
deleted file mode 100644
index 7e36bad0e..000000000
--- a/sqlchain/storage/storage.go
+++ /dev/null
@@ -1,438 +0,0 @@
-/*
- * Copyright 2018 The CovenantSQL Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package storage
-
-import (
-	"context"
-	"database/sql"
-	"errors"
-	"fmt"
-	"io"
-	"sync"
-
-	"github.com/CovenantSQL/CovenantSQL/twopc"
-	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	// Register CovenantSQL/go-sqlite3-encrypt engine.
-	_ "github.com/CovenantSQL/go-sqlite3-encrypt"
-)
-
-var (
-	index = struct {
-		sync.Mutex
-		db map[string]*sql.DB
-	}{
-		db: make(map[string]*sql.DB),
-	}
-)
-
-// Query represents the single query of sqlite.
-type Query struct {
-	Pattern string
-	Args    []sql.NamedArg
-}
-
-// ExecLog represents the execution log of sqlite.
-type ExecLog struct {
-	ConnectionID uint64
-	SeqNo        uint64
-	Timestamp    int64
-	Queries      []Query
-}
-
-// ExecResult represents the execution result of sqlite.
-type ExecResult struct {
-	LastInsertID int64
-	RowsAffected int64
-}
-
-func openDB(dsn string) (db *sql.DB, err error) {
-	// Rebuild DSN.
-	d, err := NewDSN(dsn)
-
-	if err != nil {
-		return nil, err
-	}
-
-	d.AddParam("_journal_mode", "WAL")
-	d.AddParam("_synchronous", "NORMAL")
-	fdsn := d.Format()
-
-	fn := d.GetFileName()
-	mode, _ := d.GetParam("mode")
-	cache, _ := d.GetParam("cache")
-
-	if (fn == ":memory:" || mode == "memory") && cache != "shared" {
-		// Return a new DB instance if it's in memory and private.
-		db, err = sql.Open("sqlite3", fdsn)
-		return
-	}
-
-	index.Lock()
-	db, ok := index.db[d.filename]
-	index.Unlock()
-
-	if !ok {
-		db, err = sql.Open("sqlite3", fdsn)
-
-		if err != nil {
-			return nil, err
-		}
-
-		index.Lock()
-		index.db[d.filename] = db
-		index.Unlock()
-	}
-
-	return
-}
-
-// TxID represents a transaction ID.
-type TxID struct {
-	ConnectionID uint64
-	SeqNo        uint64
-	Timestamp    int64
-}
-
-func equalTxID(x, y *TxID) bool {
-	return x.ConnectionID == y.ConnectionID && x.SeqNo == y.SeqNo && x.Timestamp == y.Timestamp
-}
-
-// Storage represents a underlying storage implementation based on sqlite3.
-type Storage struct {
-	sync.Mutex
-	dsn     string
-	db      *sql.DB
-	tx      *sql.Tx // Current tx
-	id      TxID
-	queries []Query
-}
-
-// New returns a new storage connected by dsn.
-func New(dsn string) (st *Storage, err error) {
-	db, err := openDB(dsn)
-
-	if err != nil {
-		return
-	}
-
-	return &Storage{
-		dsn: dsn,
-		db:  db,
-	}, nil
-}
-
-// Prepare implements prepare method of two-phase commit worker.
-func (s *Storage) Prepare(ctx context.Context, wb twopc.WriteBatch) (err error) {
-	el, ok := wb.(*ExecLog)
-
-	if !ok {
-		return errors.New("unexpected WriteBatch type")
-	}
-
-	s.Lock()
-	defer s.Unlock()
-
-	if s.tx != nil {
-		if equalTxID(&s.id, &TxID{el.ConnectionID, el.SeqNo, el.Timestamp}) {
-			s.queries = el.Queries
-			return nil
-		}
-
-		return fmt.Errorf("twopc: inconsistent state, currently in tx: "+
-			"conn = %d, seq = %d, time = %d", s.id.ConnectionID, s.id.SeqNo, s.id.Timestamp)
-	}
-
-	s.tx, err = s.db.BeginTx(ctx, nil)
-
-	if err != nil {
-		return
-	}
-
-	s.id = TxID{el.ConnectionID, el.SeqNo, el.Timestamp}
-	s.queries = el.Queries
-
-	return nil
-}
-
-// Commit implements commit method of two-phase commit worker.
-func (s *Storage) Commit(ctx context.Context, wb twopc.WriteBatch) (result interface{}, err error) {
-	el, ok := wb.(*ExecLog)
-
-	if !ok {
-		err = errors.New("unexpected WriteBatch type")
-		return
-	}
-
-	s.Lock()
-	defer s.Unlock()
-
-	if s.tx != nil {
-		if equalTxID(&s.id, &TxID{el.ConnectionID, el.SeqNo, el.Timestamp}) {
-			// get last insert id and affected rows result
-			execResult := ExecResult{}
-
-			for _, q := range s.queries {
-				// convert arguments types
-				args := make([]interface{}, len(q.Args))
-
-				for i, v := range q.Args {
-					args[i] = v
-				}
-
-				var res sql.Result
-				res, err = s.tx.ExecContext(ctx, q.Pattern, args...)
-
-				if err != nil {
-					log.WithError(err).Debug("commit query failed")
-					s.tx.Rollback()
-					s.tx = nil
-					s.queries = nil
-					return
-				}
-
-				lastInsertID, _ := res.LastInsertId()
-				rowsAffected, _ := res.RowsAffected()
-
-				execResult.LastInsertID = lastInsertID
-				execResult.RowsAffected += rowsAffected
-			}
-
-			s.tx.Commit()
-			s.tx = nil
-			s.queries = nil
-			result = execResult
-
-			return
-		}
-
-		err = fmt.Errorf("twopc: inconsistent state, currently in tx: "+
-			"conn = %d, seq = %d, time = %d", s.id.ConnectionID, s.id.SeqNo, s.id.Timestamp)
-		return
-	}
-
-	err = errors.New("twopc: tx not prepared")
-	return
-}
-
-// Rollback implements rollback method of two-phase commit worker.
-func (s *Storage) Rollback(ctx context.Context, wb twopc.WriteBatch) (err error) {
-	el, ok := wb.(*ExecLog)
-
-	if !ok {
-		return errors.New("unexpected WriteBatch type")
-	}
-
-	s.Lock()
-	defer s.Unlock()
-
-	if !equalTxID(&s.id, &TxID{el.ConnectionID, el.SeqNo, el.Timestamp}) {
-		return fmt.Errorf("twopc: inconsistent state, currently in tx: "+
-			"conn = %d, seq = %d, time = %d", s.id.ConnectionID, s.id.SeqNo, s.id.Timestamp)
-	}
-
-	if s.tx != nil {
-		s.tx.Rollback()
-		s.tx = nil
-		s.queries = nil
-	}
-
-	return nil
-}
-
-// Query implements read-only query feature.
-func (s *Storage) Query(ctx context.Context, queries []Query) (columns []string, types []string,
-	data [][]interface{}, err error) {
-	data = make([][]interface{}, 0)
-
-	if len(queries) == 0 {
-		return
-	}
-
-	var tx *sql.Tx
-	var txOptions = &sql.TxOptions{
-		ReadOnly: true,
-	}
-
-	if tx, err = s.db.BeginTx(ctx, txOptions); err != nil {
-		return
-	}
-
-	// always rollback on complete
-	defer tx.Rollback()
-
-	q := queries[len(queries)-1]
-
-	// convert arguments types
-	args := make([]interface{}, len(q.Args))
-
-	for i, v := range q.Args {
-		args[i] = v
-	}
-
-	var rows *sql.Rows
-	if rows, err = tx.Query(q.Pattern, args...); err != nil {
-		return
-	}
-
-	// free result set
-	defer rows.Close()
-
-	// get rows meta
-	if columns, err = rows.Columns(); err != nil {
-		return
-	}
-
-	// if there is empty columns, treat result as empty
-	if len(columns) == 0 {
-		return
-	}
-
-	// get types meta
-	if types, err = s.transformColumnTypes(rows.ColumnTypes()); err != nil {
-		return
-	}
-
-	rs := newRowScanner(len(columns))
-
-	for rows.Next() {
-		err = rows.Scan(rs.ScanArgs()...)
-		if err != nil {
-			return
-		}
-
-		data = append(data, rs.GetRow())
-	}
-
-	err = rows.Err()
-	return
-}
-
-// Exec implements write query feature.
-func (s *Storage) Exec(ctx context.Context, queries []Query) (result ExecResult, err error) {
-	if len(queries) == 0 {
-		return
-	}
-
-	var tx *sql.Tx
-	var txOptions = &sql.TxOptions{
-		ReadOnly: false,
-	}
-
-	if tx, err = s.db.BeginTx(ctx, txOptions); err != nil {
-		return
-	}
-
-	defer tx.Rollback()
-
-	for _, q := range queries {
-		// convert arguments types
-		args := make([]interface{}, len(q.Args))
-
-		for i, v := range q.Args {
-			args[i] = v
-		}
-
-		var r sql.Result
-		if r, err = tx.Exec(q.Pattern, args...); err != nil {
-			log.WithError(err).Debug("execute query failed")
-			return
-		}
-
-		var affected int64
-		affected, _ = r.RowsAffected()
-		result.RowsAffected += affected
-		result.LastInsertID, _ = r.LastInsertId()
-	}
-
-	tx.Commit()
-
-	return
-}
-
-// Close implements database safe close feature.
-func (s *Storage) Close() (err error) {
-	d, err := NewDSN(s.dsn)
-	if err != nil {
-		return
-	}
-
-	index.Lock()
-	defer index.Unlock()
-	delete(index.db, d.filename)
-	return s.db.Close()
-}
-
-func (s *Storage) transformColumnTypes(columnTypes []*sql.ColumnType, e error) (types []string, err error) {
-	if e != nil {
-		err = e
-		return
-	}
-
-	types = make([]string, len(columnTypes))
-
-	for i, c := range columnTypes {
-		types[i] = c.DatabaseTypeName()
-	}
-
-	return
-}
-
-// golang does trick convert, use rowScanner to return the original result type in sqlite3 driver
-type rowScanner struct {
-	fieldCnt int
-	column   int           // current column
-	fields   []interface{} // temp fields
-	scanArgs []interface{}
-}
-
-func newRowScanner(fieldCnt int) (s *rowScanner) {
-	s = &rowScanner{
-		fieldCnt: fieldCnt,
-		column:   0,
-		fields:   make([]interface{}, fieldCnt),
-		scanArgs: make([]interface{}, fieldCnt),
-	}
-
-	for i := 0; i != fieldCnt; i++ {
-		s.scanArgs[i] = s
-	}
-
-	return
-}
-
-func (s *rowScanner) Scan(src interface{}) error {
-	if s.fieldCnt <= s.column {
-		// read complete
-		return io.EOF
-	}
-
-	s.fields[s.column] = src
-	s.column++
-
-	return nil
-}
-
-func (s *rowScanner) GetRow() []interface{} {
-	return s.fields
-}
-
-func (s *rowScanner) ScanArgs() []interface{} {
-	// reset
-	s.column = 0
-	s.fields = make([]interface{}, s.fieldCnt)
-	return s.scanArgs
-}
diff --git a/sqlchain/storage/storage_test.go b/sqlchain/storage/storage_test.go
deleted file mode 100644
index 0cda67128..000000000
--- a/sqlchain/storage/storage_test.go
+++ /dev/null
@@ -1,353 +0,0 @@
-/*
- * Copyright 2018 The CovenantSQL Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package storage
-
-import (
-	"context"
-	"database/sql"
-	"fmt"
-	"io/ioutil"
-	"reflect"
-	"testing"
-	"time"
-)
-
-func newQuery(query string, args ...interface{}) (q Query) {
-	q.Pattern = query
-
-	// convert args
-	q.Args = make([]sql.NamedArg, len(args))
-	for i, v := range args {
-		q.Args[i] = sql.Named("", v)
-	}
-
-	return
-}
-
-func newNamedQuery(query string, args map[string]interface{}) (q Query) {
-	q.Pattern = query
-	q.Args = make([]sql.NamedArg, len(args))
-	i := 0
-
-	// convert args
-	for n, v := range args {
-		q.Args[i] = sql.Named(n, v)
-		i++
-	}
-
-	return
-}
-
-func TestBadType(t *testing.T) {
-	fl, err := ioutil.TempFile("", "sqlite3-")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	st, err := New(fmt.Sprintf("file:%s", fl.Name()))
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	if err = st.Prepare(context.Background(), struct{}{}); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %v", err)
-	}
-
-	if _, err = st.Commit(context.Background(), struct{}{}); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %v", err)
-	}
-
-	if err = st.Rollback(context.Background(), struct{}{}); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %v", err)
-	}
-}
-
-func TestStorage(t *testing.T) {
-	fl, err := ioutil.TempFile("", "sqlite3-")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	st, err := New(fmt.Sprintf("file:%s", fl.Name()))
-
-	if err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	el1 := &ExecLog{
-		ConnectionID: 1,
-		SeqNo:        1,
-		Timestamp:    time.Now().UnixNano(),
-		Queries: []Query{
-			newQuery("CREATE TABLE IF NOT EXISTS `kv` (`key` TEXT PRIMARY KEY, `value` BLOB)"),
-			newQuery("INSERT OR IGNORE INTO `kv` VALUES ('k0', NULL)"),
-			newQuery("INSERT OR IGNORE INTO `kv` VALUES ('k1', 'v1')"),
-			newQuery("INSERT OR IGNORE INTO `kv` VALUES ('k2', 'v2')"),
-			newQuery("INSERT OR IGNORE INTO `kv` VALUES ('k3', 'v3')"),
-			newQuery("INSERT OR REPLACE INTO `kv` VALUES ('k3', 'v3-2')"),
-			newQuery("DELETE FROM `kv` WHERE `key`='k2'"),
-		},
-	}
-
-	el2 := &ExecLog{
-		ConnectionID: 1,
-		SeqNo:        2,
-		Timestamp:    time.Now().UnixNano(),
-		Queries: []Query{
-			newQuery("INSERT OR REPLACE INTO `kv` VALUES ('k1', 'v1-2')"),
-		},
-	}
-
-	if err = st.Prepare(context.Background(), el1); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	if err = st.Prepare(context.Background(), el1); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	}
-
-	if err = st.Prepare(context.Background(), el2); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %v", err)
-	}
-
-	if _, err = st.Commit(context.Background(), el2); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %v", err)
-	}
-
-	if err = st.Rollback(context.Background(), el2); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %v", err)
-	}
-
-	var res interface{}
-	if res, err = st.Commit(context.Background(), el1); err != nil {
-		t.Fatalf("Error occurred: %v", err)
-	} else {
-		result := res.(ExecResult)
-		t.Logf("Result: %v", result)
-	}
-
-	// test query
-	columns, types, data, err := st.Query(context.Background(),
-		[]Query{newQuery("SELECT * FROM `kv` ORDER BY `key` ASC")})
-
-	if err != nil {
-		t.Fatalf("Query failed: %v", err.Error())
-	}
-	if !reflect.DeepEqual(columns, []string{"key", "value"}) {
-		t.Fatalf("Error column result: %v", columns)
-	}
-	if !reflect.DeepEqual(types, []string{"TEXT", "BLOB"}) {
-		t.Fatalf("Error types result: %v", types)
-	}
-	if len(data) != 3 {
-		t.Fatalf("Error result count: %v, should be 3", len(data))
-	} else {
-		// compare rows
-		should1 := []interface{}{[]byte("k0"), nil}
-		should2 := []interface{}{[]byte("k1"), []byte("v1")}
-		should3 := []interface{}{[]byte("k3"), []byte("v3-2")}
-		t.Logf("Rows: %v", data)
-		if !reflect.DeepEqual(data[0], should1) {
-			t.Fatalf("Error result row: %v, should: %v", data[0], should1)
-		}
-		if !reflect.DeepEqual(data[1], should2) {
-			t.Fatalf("Error result row: %v, should: %v", data[1], should2)
-		}
-		if !reflect.DeepEqual(data[2], should3) {
-			t.Fatalf("Error result row: %v, should: %v", data[2], should2)
-		}
-	}
-
-	// test query with projection
-	columns, types, data, err = st.Query(context.Background(),
-		[]Query{newQuery("SELECT `key` FROM `kv` ORDER BY `key` ASC")})
-
-	if err != nil {
-		t.Fatalf("Query failed: %v", err.Error())
-	}
-	if !reflect.DeepEqual(columns, []string{"key"}) {
-		t.Fatalf("Error column result: %v", columns)
-	}
-	if !reflect.DeepEqual(types, []string{"TEXT"}) {
-		t.Fatalf("Error types result: %v", types)
-	}
-	if len(data) != 3 {
-		t.Fatalf("Error result count: %v, should be 3", len(data))
-	} else {
-		// compare rows
-		should1 := []interface{}{[]byte("k0")}
-		should2 := []interface{}{[]byte("k1")}
-		should3 := []interface{}{[]byte("k3")}
-		t.Logf("Rows: %v", data)
-		if !reflect.DeepEqual(data[0], should1) {
-			t.Fatalf("Error result row: %v, should: %v", data[0], should1)
-		}
-		if !reflect.DeepEqual(data[1], should2) {
-			t.Fatalf("Error result row: %v, should: %v", data[1], should2)
-		}
-		if !reflect.DeepEqual(data[2], should3) {
-			t.Fatalf("Error result row: %v, should: %v", data[2], should2)
-		}
-	}
-
-	// test query with condition
-	columns, types, data, err = st.Query(context.Background(),
-		[]Query{newQuery("SELECT `key` FROM `kv` WHERE `value` IS NOT NULL ORDER BY `key` ASC")})
-
-	if err != nil {
-		t.Fatalf("Query failed: %v", err.Error())
-	}
-	if !reflect.DeepEqual(columns, []string{"key"}) {
-		t.Fatalf("Error column result: %v", columns)
-	}
-	if !reflect.DeepEqual(types, []string{"TEXT"}) {
-		t.Fatalf("Error types result: %v", types)
-	}
-	if len(data) != 2 {
-		t.Fatalf("Error result count: %v, should be 3", len(data))
-	} else {
-		// compare rows
-		should1 := []interface{}{[]byte("k1")}
-		should2 := []interface{}{[]byte("k3")}
-		t.Logf("Rows: %v", data)
-		if !reflect.DeepEqual(data[0], should1) {
-			t.Fatalf("Error result row: %v, should: %v", data[0], should1)
-		}
-		if !reflect.DeepEqual(data[1], should2) {
-			t.Fatalf("Error result row: %v, should: %v", data[1], should2)
-		}
-	}
-
-	// test failed query
-	columns, types, data, err = st.Query(context.Background(), []Query{newQuery("SQL???? WHAT!!!!")})
-
-	if err == nil {
-		t.Fatal("Query should failed")
-	} else {
-		t.Logf("Query failed as expected with: %v", err.Error())
-	}
-
-	// test non-read query
-	columns, types, data, err = st.Query(context.Background(),
-		[]Query{newQuery("DELETE FROM `kv` WHERE `value` IS NULL")})
-
-	execResult, err := st.Exec(context.Background(),
-		[]Query{newQuery("INSERT OR REPLACE INTO `kv` VALUES ('k4', 'v4')")})
-	if err != nil || execResult.RowsAffected != 1 {
-		t.Fatalf("Exec INSERT failed: %v", err)
-	}
-	// test with arguments
-	execResult, err = st.Exec(context.Background(), []Query{newQuery("DELETE FROM `kv` WHERE `key`='k4'")})
-	if err != nil || execResult.RowsAffected != 1 {
-		t.Fatalf("Exec DELETE failed: %v", err)
-	}
-	execResult, err = st.Exec(context.Background(),
-		[]Query{newQuery("DELETE FROM `kv` WHERE `key`=?", "not_exist")})
-	if err != nil || execResult.RowsAffected != 0 {
-		t.Fatalf("Exec DELETE failed: %v", err)
-	}
-
-	// test again
-	columns, types, data, err = st.Query(context.Background(), []Query{newQuery("SELECT `key` FROM `kv`")})
-	if err != nil {
-		t.Fatalf("Query failed: %v", err.Error())
-	} else if len(data) != 3 {
-		t.Fatalf("Last write query should not take any effect, row count: %v", len(data))
-	} else {
-		t.Logf("Rows: %v", data)
-	}
-
-	// test with select
-	columns, types, data, err = st.Query(context.Background(),
-		[]Query{newQuery("SELECT `key` FROM `kv` WHERE `key` IN (?)", "k1")})
-	if err != nil {
-		t.Fatalf("Query failed: %v", err.Error())
-	} else if len(data) != 1 {
-		t.Fatalf("Should only have one record, but actually %v", len(data))
-	} else {
-		t.Logf("Rows: %v", data)
-	}
-
-	// test with select with named arguments
-	columns, types, data, err = st.Query(context.Background(),
-		[]Query{newNamedQuery("SELECT `key` FROM `kv` WHERE `key` IN (:test2, :test1)", map[string]interface{}{
-			"test1": "k1",
-			"test2": "k3",
-		})})
-	if err != nil {
-		t.Fatalf("Query failed: %v", err.Error())
-	} else if len(data) != 2 {
-		t.Fatalf("Should only have two records, but actually %v", len(data))
-	} else {
-		t.Logf("Rows: %v", data)
-	}
-
-	// test with function
-	columns, types, data, err = st.Query(context.Background(),
-		[]Query{newQuery("SELECT COUNT(1) AS `c` FROM `kv`")})
-	if err != nil {
-		t.Fatalf("Query failed: %v", err.Error())
-	} else {
-		if len(columns) != 1 {
-			t.Fatalf("Query result should contain only one column, now %v", len(columns))
-		} else if columns[0] != "c" {
-			t.Fatalf("Query result column name is not defined alias, but :%v", columns[0])
-		}
-		if len(types) != 1 {
-			t.Fatalf("Query result should contain only one column, now %v", len(types))
-		} else {
-			t.Logf("Query result type is: %v", types[0])
-		}
-		if len(data) != 1 || len(data[0]) != 1 {
-			t.Fatalf("Query result should contain only one row and one column, now %v", data)
-		} else if !reflect.DeepEqual(data[0][0], int64(3)) {
-			t.Fatalf("Query result should be table row count 3, but: %v", data[0])
-		}
-	}
-
-	// test with timestamp fields
-	_, err = st.Exec(context.Background(), []Query{
-		newQuery("CREATE TABLE `tm` (tm TIMESTAMP)"),
-		newQuery("INSERT INTO `tm` VALUES(DATE('NOW'))"),
-	})
-	if err != nil {
-		t.Fatalf("Query failed: %v", err.Error())
-	} else {
-		// query for values
-		_, _, data, err = st.Query(context.Background(), []Query{newQuery("SELECT `tm` FROM `tm`")})
-		if len(data) != 1 || len(data[0]) != 1 {
-			t.Fatalf("Query result should contain only one row and one column, now %v", data)
-		} else if !reflect.TypeOf(data[0][0]).AssignableTo(reflect.TypeOf(time.Time{})) {
-			t.Fatalf("Query result should be time.Time type, but: %v", reflect.TypeOf(data[0][0]).String())
-		}
-	}
-}
diff --git a/sqlchain/xxx_test.go b/sqlchain/xxx_test.go
index 15c814c9b..3e45a73b3 100644
--- a/sqlchain/xxx_test.go
+++ b/sqlchain/xxx_test.go
@@ -28,11 +28,11 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
 	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
 	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
 	"github.com/CovenantSQL/CovenantSQL/pow/cpuminer"
 	"github.com/CovenantSQL/CovenantSQL/proto"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 )
 
 var (
@@ -105,8 +105,8 @@ func createRandomStrings(offset, length, soffset, slength int) (s []string) {
 	return
 }
 
-func createRandomStorageQueries(offset, length, soffset, slength int) (qs []wt.Query) {
-	qs = make([]wt.Query, rand.Intn(length)+offset)
+func createRandomStorageQueries(offset, length, soffset, slength int) (qs []types.Query) {
+	qs = make([]types.Query, rand.Intn(length)+offset)
 
 	for i := range qs {
 		createRandomString(soffset, slength, &qs[i].Pattern)
@@ -119,11 +119,11 @@ func createRandomTimeAfter(now time.Time, maxDelayMillisecond int) time.Time {
 	return now.Add(time.Duration(rand.Intn(maxDelayMillisecond)+1) * time.Millisecond)
 }
 
-func createRandomQueryRequest(cli *nodeProfile) (r *wt.SignedRequestHeader, err error) {
-	req := &wt.Request{
-		Header: wt.SignedRequestHeader{
-			RequestHeader: wt.RequestHeader{
-				QueryType:    wt.QueryType(rand.Intn(2)),
+func createRandomQueryRequest(cli *nodeProfile) (r *types.SignedRequestHeader, err error) {
+	req := &types.Request{
+		Header: types.SignedRequestHeader{
+			RequestHeader: types.RequestHeader{
+				QueryType:    types.QueryType(rand.Intn(2)),
 				NodeID:       cli.NodeID,
 				ConnectionID: uint64(rand.Int63()),
 				SeqNo:        uint64(rand.Int63()),
@@ -131,7 +131,7 @@ func createRandomQueryRequest(cli *nodeProfile) (r *wt.SignedRequestHeader, err
 				// BatchCount and QueriesHash will be set by req.Sign()
 			},
 		},
-		Payload: wt.RequestPayload{
+		Payload: types.RequestPayload{
 			Queries: createRandomStorageQueries(10, 10, 10, 10),
 		},
 	}
@@ -147,7 +147,7 @@ func createRandomQueryRequest(cli *nodeProfile) (r *wt.SignedRequestHeader, err
 }
 
 func createRandomQueryResponse(cli, worker *nodeProfile) (
-	r *wt.SignedResponseHeader, err error,
+	r *types.SignedResponseHeader, err error,
 ) {
 	req, err := createRandomQueryRequest(cli)
 
@@ -155,18 +155,18 @@ func createRandomQueryResponse(cli, worker *nodeProfile) (
 		return
 	}
 
-	resp := &wt.Response{
-		Header: wt.SignedResponseHeader{
-			ResponseHeader: wt.ResponseHeader{
+	resp := &types.Response{
+		Header: types.SignedResponseHeader{
+			ResponseHeader: types.ResponseHeader{
 				Request:   *req,
 				NodeID:    worker.NodeID,
 				Timestamp: createRandomTimeAfter(req.Timestamp, 100),
 			},
 		},
-		Payload: wt.ResponsePayload{
+		Payload: types.ResponsePayload{
 			Columns:   createRandomStrings(10, 10, 10, 10),
 			DeclTypes: createRandomStrings(10, 10, 10, 10),
-			Rows:      make([]wt.ResponseRow, rand.Intn(10)+10),
+			Rows:      make([]types.ResponseRow, rand.Intn(10)+10),
 		},
 	}
 
@@ -186,21 +186,21 @@ func createRandomQueryResponse(cli, worker *nodeProfile) (
 	return
 }
 
-func createRandomQueryResponseWithRequest(req *wt.SignedRequestHeader, worker *nodeProfile) (
-	r *wt.SignedResponseHeader, err error,
+func createRandomQueryResponseWithRequest(req *types.SignedRequestHeader, worker *nodeProfile) (
+	r *types.SignedResponseHeader, err error,
 ) {
-	resp := &wt.Response{
-		Header: wt.SignedResponseHeader{
-			ResponseHeader: wt.ResponseHeader{
+	resp := &types.Response{
+		Header: types.SignedResponseHeader{
+			ResponseHeader: types.ResponseHeader{
 				Request:   *req,
 				NodeID:    worker.NodeID,
 				Timestamp: createRandomTimeAfter(req.Timestamp, 100),
 			},
 		},
-		Payload: wt.ResponsePayload{
+		Payload: types.ResponsePayload{
 			Columns:   createRandomStrings(10, 10, 10, 10),
 			DeclTypes: createRandomStrings(10, 10, 10, 10),
-			Rows:      make([]wt.ResponseRow, rand.Intn(10)+10),
+			Rows:      make([]types.ResponseRow, rand.Intn(10)+10),
 		},
 	}
 
@@ -220,12 +220,12 @@ func createRandomQueryResponseWithRequest(req *wt.SignedRequestHeader, worker *n
 	return
 }
 
-func createRandomQueryAckWithResponse(resp *wt.SignedResponseHeader, cli *nodeProfile) (
-	r *wt.SignedAckHeader, err error,
+func createRandomQueryAckWithResponse(resp *types.SignedResponseHeader, cli *nodeProfile) (
+	r *types.SignedAckHeader, err error,
 ) {
-	ack := &wt.Ack{
-		Header: wt.SignedAckHeader{
-			AckHeader: wt.AckHeader{
+	ack := &types.Ack{
+		Header: types.SignedAckHeader{
+			AckHeader: types.AckHeader{
 				Response:  *resp,
 				NodeID:    cli.NodeID,
 				Timestamp: createRandomTimeAfter(resp.Timestamp, 100),
@@ -241,16 +241,16 @@ func createRandomQueryAckWithResponse(resp *wt.SignedResponseHeader, cli *nodePr
 	return
 }
 
-func createRandomQueryAck(cli, worker *nodeProfile) (r *wt.SignedAckHeader, err error) {
+func createRandomQueryAck(cli, worker *nodeProfile) (r *types.SignedAckHeader, err error) {
 	resp, err := createRandomQueryResponse(cli, worker)
 
 	if err != nil {
 		return
 	}
 
-	ack := &wt.Ack{
-		Header: wt.SignedAckHeader{
-			AckHeader: wt.AckHeader{
+	ack := &types.Ack{
+		Header: types.SignedAckHeader{
+			AckHeader: types.AckHeader{
 				Response:  *resp,
 				NodeID:    cli.NodeID,
 				Timestamp: createRandomTimeAfter(resp.Timestamp, 100),
@@ -266,7 +266,7 @@ func createRandomQueryAck(cli, worker *nodeProfile) (r *wt.SignedAckHeader, err
 	return
 }
 
-func createRandomNodesAndAck() (r *wt.SignedAckHeader, err error) {
+func createRandomNodesAndAck() (r *types.SignedAckHeader, err error) {
 	cli, err := newRandomNode()
 
 	if err != nil {
@@ -320,7 +320,7 @@ func registerNodesWithPublicKey(pub *asymmetric.PublicKey, diff int, num int) (
 	return
 }
 
-func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error) {
+func createRandomBlock(parent hash.Hash, isGenesis bool) (b *types.Block, err error) {
 	// Generate key pair
 	priv, pub, err := asymmetric.GenSecp256k1KeyPair()
 
@@ -331,9 +331,9 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 	h := hash.Hash{}
 	rand.Read(h[:])
 
-	b = &ct.Block{
-		SignedHeader: ct.SignedHeader{
-			Header: ct.Header{
+	b = &types.Block{
+		SignedHeader: types.SignedHeader{
+			Header: types.Header{
 				Version:     0x01000000,
 				Producer:    proto.NodeID(h.String()),
 				GenesisHash: genesisHash,
@@ -346,7 +346,13 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 	for i, n := 0, rand.Intn(10)+10; i < n; i++ {
 		h := &hash.Hash{}
 		rand.Read(h[:])
-		b.PushAckedQuery(h)
+		b.Acks = []*types.SignedAckHeader{
+			{
+				DefaultHashSignVerifierImpl: verifier.DefaultHashSignVerifierImpl{
+					DataHash: *h,
+				},
+			},
+		}
 	}
 
 	if isGenesis {
@@ -358,7 +364,6 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 			return
 		}
 
-		b.Queries = nil
 		b.SignedHeader.GenesisHash = hash.Hash{}
 		b.SignedHeader.Header.Producer = proto.NodeID(nis[0].Hash.String())
 	}
@@ -367,9 +372,9 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 	return
 }
 
-func createRandomQueries(x int) (acks []*wt.SignedAckHeader, err error) {
+func createRandomQueries(x int) (acks []*types.SignedAckHeader, err error) {
 	n := rand.Intn(x)
-	acks = make([]*wt.SignedAckHeader, n)
+	acks = make([]*types.SignedAckHeader, n)
 
 	for i := range acks {
 		if acks[i], err = createRandomNodesAndAck(); err != nil {
@@ -380,8 +385,8 @@ func createRandomQueries(x int) (acks []*wt.SignedAckHeader, err error) {
 	return
 }
 
-func createRandomBlockWithQueries(genesis, parent hash.Hash, acks []*wt.SignedAckHeader) (
-	b *ct.Block, err error,
+func createRandomBlockWithQueries(genesis, parent hash.Hash, acks []*types.SignedAckHeader) (
+	b *types.Block, err error,
 ) {
 	// Generate key pair
 	priv, _, err := asymmetric.GenSecp256k1KeyPair()
@@ -393,9 +398,9 @@ func createRandomBlockWithQueries(genesis, parent hash.Hash, acks []*wt.SignedAc
 	h := hash.Hash{}
 	rand.Read(h[:])
 
-	b = &ct.Block{
-		SignedHeader: ct.SignedHeader{
-			Header: ct.Header{
+	b = &types.Block{
+		SignedHeader: types.SignedHeader{
+			Header: types.Header{
 				Version:     0x01000000,
 				Producer:    proto.NodeID(h.String()),
 				GenesisHash: genesis,
@@ -405,10 +410,6 @@ func createRandomBlockWithQueries(genesis, parent hash.Hash, acks []*wt.SignedAc
 		},
 	}
 
-	for _, ack := range acks {
-		b.PushAckedQuery(&ack.Hash)
-	}
-
 	err = b.PackAndSignBlock(priv)
 	return
 }
diff --git a/sqlchain/storage/doc.go b/storage/doc.go
similarity index 100%
rename from sqlchain/storage/doc.go
rename to storage/doc.go
diff --git a/sqlchain/storage/dsn.go b/storage/dsn.go
similarity index 86%
rename from sqlchain/storage/dsn.go
rename to storage/dsn.go
index 08177de94..e74663823 100644
--- a/sqlchain/storage/dsn.go
+++ b/storage/dsn.go
@@ -82,7 +82,11 @@ func (dsn *DSN) AddParam(key, value string) {
 		dsn.params = make(map[string]string)
 	}
 
-	dsn.params[key] = value
+	if value == "" {
+		delete(dsn.params, key)
+	} else {
+		dsn.params[key] = value
+	}
 }
 
 // GetParam gets the value.
@@ -90,3 +94,16 @@ func (dsn *DSN) GetParam(key string) (value string, ok bool) {
 	value, ok = dsn.params[key]
 	return
 }
+
+// Clone returns a copy of current dsn.
+func (dsn *DSN) Clone() (copy *DSN) {
+	copy = &DSN{}
+	copy.filename = dsn.filename
+	copy.params = make(map[string]string, len(dsn.params))
+
+	for k, v := range dsn.params {
+		copy.params[k] = v
+	}
+
+	return
+}
diff --git a/sqlchain/storage/dsn_test.go b/storage/dsn_test.go
similarity index 100%
rename from sqlchain/storage/dsn_test.go
rename to storage/dsn_test.go
diff --git a/storage/storage.go b/storage/storage.go
index 55141a8d9..7e36bad0e 100644
--- a/storage/storage.go
+++ b/storage/storage.go
@@ -14,371 +14,425 @@
  * limitations under the License.
  */
 
-// Package storage implements simple key-value storage interfaces based on sqlite3.
-//
-// Although a sql.DB should be safe for concurrent use according to
-// https://golang.org/pkg/database/sql/#OpenDB, the go-sqlite3 implementation only guarantees
-// the safety of concurrent readers. See https://github.com/mattn/go-sqlite3/issues/148 for details.
-//
-// As a result, here are some suggestions:
-//
-//	1. Perform as many concurrent GetValue(s) operations as you like;
-//	2. Use only one goroutine to perform SetValue(s)/DelValue(s) operations;
-//	3. Or implement a simple busy waiting yourself on a go-sqlite3.ErrLocked error if you must use
-//	   concurrent writers.
 package storage
 
 import (
+	"context"
 	"database/sql"
+	"errors"
 	"fmt"
+	"io"
 	"sync"
+
+	"github.com/CovenantSQL/CovenantSQL/twopc"
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
 	// Register CovenantSQL/go-sqlite3-encrypt engine.
 	_ "github.com/CovenantSQL/go-sqlite3-encrypt"
 )
 
 var (
 	index = struct {
-		mu *sync.Mutex
+		sync.Mutex
 		db map[string]*sql.DB
 	}{
-		&sync.Mutex{},
-		make(map[string]*sql.DB),
+		db: make(map[string]*sql.DB),
 	}
 )
 
-func openDB(dsn string) (db *sql.DB, err error) {
-	index.mu.Lock()
-	defer index.mu.Unlock()
-
-	db = index.db[dsn]
-	if db == nil {
-		db, err = sql.Open("sqlite3", dsn)
-		if err != nil {
-			return nil, err
-		}
-
-		index.db[dsn] = db
-	}
-
-	return db, err
+// Query represents the single query of sqlite.
+type Query struct {
+	Pattern string
+	Args    []sql.NamedArg
 }
 
-// Storage represents a key-value storage.
-type Storage struct {
-	dsn   string
-	table string
-	db    *sql.DB
+// ExecLog represents the execution log of sqlite.
+type ExecLog struct {
+	ConnectionID uint64
+	SeqNo        uint64
+	Timestamp    int64
+	Queries      []Query
 }
 
-// KV represents a key-value pair.
-type KV struct {
-	Key   string
-	Value []byte
+// ExecResult represents the execution result of sqlite.
+type ExecResult struct {
+	LastInsertID int64
+	RowsAffected int64
 }
 
-// OpenStorage opens a database using the specified DSN and ensures that the specified table exists.
-func OpenStorage(dsn string, table string) (st *Storage, err error) {
-	// Open database
-	var db *sql.DB
-	db, err = openDB(dsn)
+func openDB(dsn string) (db *sql.DB, err error) {
+	// Rebuild DSN.
+	d, err := NewDSN(dsn)
 
 	if err != nil {
-		return st, err
+		return nil, err
 	}
 
-	// Ensure table
-	stmt := fmt.Sprintf("CREATE TABLE IF NOT EXISTS `%s` (`key` TEXT PRIMARY KEY, `value` BLOB)",
-		table)
+	d.AddParam("_journal_mode", "WAL")
+	d.AddParam("_synchronous", "NORMAL")
+	fdsn := d.Format()
+
+	fn := d.GetFileName()
+	mode, _ := d.GetParam("mode")
+	cache, _ := d.GetParam("cache")
 
-	if _, err = db.Exec(stmt); err != nil {
-		return st, err
+	if (fn == ":memory:" || mode == "memory") && cache != "shared" {
+		// Return a new DB instance if it's in memory and private.
+		db, err = sql.Open("sqlite3", fdsn)
+		return
 	}
 
-	st = &Storage{dsn, table, db}
-	return st, err
-}
+	index.Lock()
+	db, ok := index.db[d.filename]
+	index.Unlock()
 
-// SetValue sets or replace the value to key.
-func (s *Storage) SetValue(key string, value []byte) (err error) {
-	stmt := fmt.Sprintf("INSERT OR REPLACE INTO `%s` (`key`, `value`) VALUES (?, ?)", s.table)
-	_, err = s.db.Exec(stmt, key, value)
+	if !ok {
+		db, err = sql.Open("sqlite3", fdsn)
 
-	return err
-}
+		if err != nil {
+			return nil, err
+		}
+
+		index.Lock()
+		index.db[d.filename] = db
+		index.Unlock()
+	}
 
-// SetValueIfNotExist sets the value to key if it doesn't exist.
-func (s *Storage) SetValueIfNotExist(key string, value []byte) (err error) {
-	stmt := fmt.Sprintf("INSERT OR IGNORE INTO `%s` (`key`, `value`) VALUES (?, ?)", s.table)
-	_, err = s.db.Exec(stmt, key, value)
+	return
+}
 
-	return err
+// TxID represents a transaction ID.
+type TxID struct {
+	ConnectionID uint64
+	SeqNo        uint64
+	Timestamp    int64
 }
 
-// DelValue deletes the value of key.
-func (s *Storage) DelValue(key string) (err error) {
-	stmt := fmt.Sprintf("DELETE FROM `%s` WHERE `key` = ?", s.table)
-	_, err = s.db.Exec(stmt, key)
+func equalTxID(x, y *TxID) bool {
+	return x.ConnectionID == y.ConnectionID && x.SeqNo == y.SeqNo && x.Timestamp == y.Timestamp
+}
 
-	return err
+// Storage represents a underlying storage implementation based on sqlite3.
+type Storage struct {
+	sync.Mutex
+	dsn     string
+	db      *sql.DB
+	tx      *sql.Tx // Current tx
+	id      TxID
+	queries []Query
 }
 
-// GetValue fetches the value of key.
-func (s *Storage) GetValue(key string) (value []byte, err error) {
-	stmt := fmt.Sprintf("SELECT `value` FROM `%s` WHERE `key` = ?", s.table)
+// New returns a new storage connected by dsn.
+func New(dsn string) (st *Storage, err error) {
+	db, err := openDB(dsn)
 
-	if err = s.db.QueryRow(stmt, key).Scan(&value); err == sql.ErrNoRows {
-		err = nil
+	if err != nil {
+		return
 	}
 
-	return value, err
+	return &Storage{
+		dsn: dsn,
+		db:  db,
+	}, nil
 }
 
-// SetValues sets or replaces the key-value pairs in kvs.
-//
-// Note that this is not a transaction. We use a prepared statement to send these queries. Each
-// call may fail while part of the queries succeed.
-func (s *Storage) SetValues(kvs []KV) (err error) {
-	stmt := fmt.Sprintf("INSERT OR REPLACE INTO `%s` (`key`, `value`) VALUES (?, ?)", s.table)
-	pStmt, err := s.db.Prepare(stmt)
+// Prepare implements prepare method of two-phase commit worker.
+func (s *Storage) Prepare(ctx context.Context, wb twopc.WriteBatch) (err error) {
+	el, ok := wb.(*ExecLog)
 
-	if err != nil {
-		return err
+	if !ok {
+		return errors.New("unexpected WriteBatch type")
 	}
 
-	defer pStmt.Close()
+	s.Lock()
+	defer s.Unlock()
 
-	for _, row := range kvs {
-		if _, err = pStmt.Exec(row.Key, row.Value); err != nil {
-			return err
+	if s.tx != nil {
+		if equalTxID(&s.id, &TxID{el.ConnectionID, el.SeqNo, el.Timestamp}) {
+			s.queries = el.Queries
+			return nil
 		}
+
+		return fmt.Errorf("twopc: inconsistent state, currently in tx: "+
+			"conn = %d, seq = %d, time = %d", s.id.ConnectionID, s.id.SeqNo, s.id.Timestamp)
 	}
 
+	s.tx, err = s.db.BeginTx(ctx, nil)
+
+	if err != nil {
+		return
+	}
+
+	s.id = TxID{el.ConnectionID, el.SeqNo, el.Timestamp}
+	s.queries = el.Queries
+
 	return nil
 }
 
-// SetValuesIfNotExist sets the key-value pairs in kvs if the key doesn't exist.
-//
-// Note that this is not a transaction. We use a prepared statement to send these queries. Each
-// call may fail while part of the queries succeed.
-func (s *Storage) SetValuesIfNotExist(kvs []KV) (err error) {
-	stmt := fmt.Sprintf("INSERT OR IGNORE INTO `%s` (`key`, `value`) VALUES (?, ?)", s.table)
-	pStmt, err := s.db.Prepare(stmt)
+// Commit implements commit method of two-phase commit worker.
+func (s *Storage) Commit(ctx context.Context, wb twopc.WriteBatch) (result interface{}, err error) {
+	el, ok := wb.(*ExecLog)
 
-	if err != nil {
-		return err
+	if !ok {
+		err = errors.New("unexpected WriteBatch type")
+		return
 	}
 
-	defer pStmt.Close()
+	s.Lock()
+	defer s.Unlock()
+
+	if s.tx != nil {
+		if equalTxID(&s.id, &TxID{el.ConnectionID, el.SeqNo, el.Timestamp}) {
+			// get last insert id and affected rows result
+			execResult := ExecResult{}
+
+			for _, q := range s.queries {
+				// convert arguments types
+				args := make([]interface{}, len(q.Args))
+
+				for i, v := range q.Args {
+					args[i] = v
+				}
+
+				var res sql.Result
+				res, err = s.tx.ExecContext(ctx, q.Pattern, args...)
+
+				if err != nil {
+					log.WithError(err).Debug("commit query failed")
+					s.tx.Rollback()
+					s.tx = nil
+					s.queries = nil
+					return
+				}
+
+				lastInsertID, _ := res.LastInsertId()
+				rowsAffected, _ := res.RowsAffected()
 
-	for _, row := range kvs {
-		if _, err = pStmt.Exec(row.Key, row.Value); err != nil {
-			return err
+				execResult.LastInsertID = lastInsertID
+				execResult.RowsAffected += rowsAffected
+			}
+
+			s.tx.Commit()
+			s.tx = nil
+			s.queries = nil
+			result = execResult
+
+			return
 		}
+
+		err = fmt.Errorf("twopc: inconsistent state, currently in tx: "+
+			"conn = %d, seq = %d, time = %d", s.id.ConnectionID, s.id.SeqNo, s.id.Timestamp)
+		return
 	}
 
-	return nil
+	err = errors.New("twopc: tx not prepared")
+	return
 }
 
-// DelValues deletes the values of the keys.
-//
-// Note that this is not a transaction. We use a prepared statement to send these queries. Each
-// call may fail while part of the queries succeed.
-func (s *Storage) DelValues(keys []string) (err error) {
-	stmt := fmt.Sprintf("DELETE FROM `%s` WHERE `key` = ?", s.table)
-	pStmt, err := s.db.Prepare(stmt)
+// Rollback implements rollback method of two-phase commit worker.
+func (s *Storage) Rollback(ctx context.Context, wb twopc.WriteBatch) (err error) {
+	el, ok := wb.(*ExecLog)
 
-	if err != nil {
-		return err
+	if !ok {
+		return errors.New("unexpected WriteBatch type")
 	}
 
-	defer pStmt.Close()
+	s.Lock()
+	defer s.Unlock()
 
-	for _, key := range keys {
-		if _, err = pStmt.Exec(key); err != nil {
-			return err
-		}
+	if !equalTxID(&s.id, &TxID{el.ConnectionID, el.SeqNo, el.Timestamp}) {
+		return fmt.Errorf("twopc: inconsistent state, currently in tx: "+
+			"conn = %d, seq = %d, time = %d", s.id.ConnectionID, s.id.SeqNo, s.id.Timestamp)
+	}
+
+	if s.tx != nil {
+		s.tx.Rollback()
+		s.tx = nil
+		s.queries = nil
 	}
 
 	return nil
 }
 
-// GetValues fetches the values of keys.
-//
-// Note that this is not a transaction. We use a prepared statement to send these queries. Each
-// call may fail while part of the queries succeed and some values may be altered during the
-// queries. But the results will be returned only if all the queries succeed.
-func (s *Storage) GetValues(keys []string) (kvs []KV, err error) {
-	stmt := fmt.Sprintf("SELECT `value` FROM `%s` WHERE `key` = ?", s.table)
-	pStmt, err := s.db.Prepare(stmt)
+// Query implements read-only query feature.
+func (s *Storage) Query(ctx context.Context, queries []Query) (columns []string, types []string,
+	data [][]interface{}, err error) {
+	data = make([][]interface{}, 0)
 
-	if err != nil {
-		return nil, err
+	if len(queries) == 0 {
+		return
+	}
+
+	var tx *sql.Tx
+	var txOptions = &sql.TxOptions{
+		ReadOnly: true,
 	}
 
-	defer pStmt.Close()
+	if tx, err = s.db.BeginTx(ctx, txOptions); err != nil {
+		return
+	}
 
-	kvs = make([]KV, len(keys))
+	// always rollback on complete
+	defer tx.Rollback()
 
-	for index, key := range keys {
-		kvs[index].Key = key
+	q := queries[len(queries)-1]
 
-		if err = pStmt.QueryRow(key).Scan(&kvs[index].Value); err != nil && err != sql.ErrNoRows {
-			return nil, err
-		}
+	// convert arguments types
+	args := make([]interface{}, len(q.Args))
+
+	for i, v := range q.Args {
+		args[i] = v
 	}
 
-	return kvs, nil
-}
+	var rows *sql.Rows
+	if rows, err = tx.Query(q.Pattern, args...); err != nil {
+		return
+	}
 
-// SetValuesTx sets or replaces the key-value pairs in kvs as a transaction.
-func (s *Storage) SetValuesTx(kvs []KV) (err error) {
-	// Begin transaction
-	tx, err := s.db.Begin()
+	// free result set
+	defer rows.Close()
 
-	if err != nil {
-		return err
+	// get rows meta
+	if columns, err = rows.Columns(); err != nil {
+		return
 	}
 
-	defer func() {
-		if err != nil {
-			tx.Rollback()
-		} else {
-			err = tx.Commit()
-		}
-	}()
-
-	// Prepare statement
-	stmt := fmt.Sprintf("INSERT OR REPLACE INTO `%s` (`key`, `value`) VALUES (?, ?)", s.table)
-	pStmt, err := tx.Prepare(stmt)
+	// if there is empty columns, treat result as empty
+	if len(columns) == 0 {
+		return
+	}
 
-	if err != nil {
-		return err
+	// get types meta
+	if types, err = s.transformColumnTypes(rows.ColumnTypes()); err != nil {
+		return
 	}
 
-	defer pStmt.Close()
+	rs := newRowScanner(len(columns))
 
-	// Execute queries
-	for _, row := range kvs {
-		if _, err = pStmt.Exec(row.Key, row.Value); err != nil {
-			return err
+	for rows.Next() {
+		err = rows.Scan(rs.ScanArgs()...)
+		if err != nil {
+			return
 		}
+
+		data = append(data, rs.GetRow())
 	}
 
-	return nil
+	err = rows.Err()
+	return
 }
 
-// SetValuesIfNotExistTx sets the key-value pairs in kvs if the key doesn't exist as a transaction.
-func (s *Storage) SetValuesIfNotExistTx(kvs []KV) (err error) {
-	// Begin transaction
-	tx, err := s.db.Begin()
+// Exec implements write query feature.
+func (s *Storage) Exec(ctx context.Context, queries []Query) (result ExecResult, err error) {
+	if len(queries) == 0 {
+		return
+	}
 
-	if err != nil {
-		return err
+	var tx *sql.Tx
+	var txOptions = &sql.TxOptions{
+		ReadOnly: false,
 	}
 
-	defer func() {
-		if err != nil {
-			tx.Rollback()
-		} else {
-			err = tx.Commit()
-		}
-	}()
+	if tx, err = s.db.BeginTx(ctx, txOptions); err != nil {
+		return
+	}
 
-	// Prepare statement
-	stmt := fmt.Sprintf("INSERT OR IGNORE INTO `%s` (`key`, `value`) VALUES (?, ?)", s.table)
-	pStmt, err := tx.Prepare(stmt)
+	defer tx.Rollback()
 
-	if err != nil {
-		return err
-	}
+	for _, q := range queries {
+		// convert arguments types
+		args := make([]interface{}, len(q.Args))
 
-	defer pStmt.Close()
+		for i, v := range q.Args {
+			args[i] = v
+		}
 
-	// Execute queries
-	for _, row := range kvs {
-		if _, err = pStmt.Exec(row.Key, row.Value); err != nil {
-			return err
+		var r sql.Result
+		if r, err = tx.Exec(q.Pattern, args...); err != nil {
+			log.WithError(err).Debug("execute query failed")
+			return
 		}
+
+		var affected int64
+		affected, _ = r.RowsAffected()
+		result.RowsAffected += affected
+		result.LastInsertID, _ = r.LastInsertId()
 	}
 
-	return nil
-}
+	tx.Commit()
 
-// DelValuesTx deletes the values of the keys as a transaction.
-func (s *Storage) DelValuesTx(keys []string) (err error) {
-	// Begin transaction
-	tx, err := s.db.Begin()
+	return
+}
 
+// Close implements database safe close feature.
+func (s *Storage) Close() (err error) {
+	d, err := NewDSN(s.dsn)
 	if err != nil {
-		return err
+		return
 	}
 
-	defer func() {
-		if err != nil {
-			tx.Rollback()
-		} else {
-			err = tx.Commit()
-		}
-	}()
-
-	// Prepare statement
-	stmt := fmt.Sprintf("DELETE FROM `%s` WHERE `key` = ?", s.table)
-	pStmt, err := tx.Prepare(stmt)
+	index.Lock()
+	defer index.Unlock()
+	delete(index.db, d.filename)
+	return s.db.Close()
+}
 
-	if err != nil {
-		return err
+func (s *Storage) transformColumnTypes(columnTypes []*sql.ColumnType, e error) (types []string, err error) {
+	if e != nil {
+		err = e
+		return
 	}
 
-	defer pStmt.Close()
+	types = make([]string, len(columnTypes))
 
-	// Execute queries
-	for _, key := range keys {
-		if _, err = pStmt.Exec(key); err != nil {
-			return err
-		}
+	for i, c := range columnTypes {
+		types[i] = c.DatabaseTypeName()
 	}
 
-	return nil
+	return
 }
 
-// GetValuesTx fetches the values of keys as a transaction.
-func (s *Storage) GetValuesTx(keys []string) (kvs []KV, err error) {
-	// Begin transaction
-	tx, err := s.db.Begin()
+// golang does trick convert, use rowScanner to return the original result type in sqlite3 driver
+type rowScanner struct {
+	fieldCnt int
+	column   int           // current column
+	fields   []interface{} // temp fields
+	scanArgs []interface{}
+}
 
-	if err != nil {
-		return nil, err
+func newRowScanner(fieldCnt int) (s *rowScanner) {
+	s = &rowScanner{
+		fieldCnt: fieldCnt,
+		column:   0,
+		fields:   make([]interface{}, fieldCnt),
+		scanArgs: make([]interface{}, fieldCnt),
 	}
 
-	defer func() {
-		if err != nil {
-			tx.Rollback()
-		} else {
-			err = tx.Commit()
-		}
-	}()
+	for i := 0; i != fieldCnt; i++ {
+		s.scanArgs[i] = s
+	}
 
-	// Prepare statement
-	stmt := fmt.Sprintf("SELECT `value` FROM `%s` WHERE `key` = ?", s.table)
-	pStmt, err := tx.Prepare(stmt)
+	return
+}
 
-	if err != nil {
-		return nil, err
+func (s *rowScanner) Scan(src interface{}) error {
+	if s.fieldCnt <= s.column {
+		// read complete
+		return io.EOF
 	}
 
-	defer pStmt.Close()
-
-	// Execute queries
-	kvs = make([]KV, len(keys))
+	s.fields[s.column] = src
+	s.column++
 
-	for index, key := range keys {
-		kvs[index].Key = key
-		err = pStmt.QueryRow(key).Scan(&kvs[index].Value)
+	return nil
+}
 
-		if err != nil && err != sql.ErrNoRows {
-			return nil, err
-		}
-	}
+func (s *rowScanner) GetRow() []interface{} {
+	return s.fields
+}
 
-	return kvs, nil
+func (s *rowScanner) ScanArgs() []interface{} {
+	// reset
+	s.column = 0
+	s.fields = make([]interface{}, s.fieldCnt)
+	return s.scanArgs
 }
diff --git a/storage/storage_test.go b/storage/storage_test.go
index 970183471..0cda67128 100644
--- a/storage/storage_test.go
+++ b/storage/storage_test.go
@@ -17,1000 +17,337 @@
 package storage
 
 import (
-	"bytes"
+	"context"
+	"database/sql"
 	"fmt"
 	"io/ioutil"
-	"math/rand"
-	"os"
 	"reflect"
-	"sync"
 	"testing"
 	"time"
 )
 
-var (
-	sampleTexts = []KV{
-		{"Philip K. Dick", []byte("All their equipment and instruments are alive.")},
-		{"Philip K. Dick", []byte("The face of the moon was in shadow.")},
-		{"Samuel R. Delany", []byte("A red flair silhouetted the jagged edge of a wing.")},
-		{"Samuel R. Delany", []byte("Mist enveloped the ship three hours out from port.")},
-		{"Samuel R. Delany", []byte("Silver mist suffused the deck of the ship.")},
-		{"Samuel R. Delany", []byte("Waves flung themselves at the blue evening.")},
-		{"Mary Shelley", []byte("I watched the storm, so beautiful yet terrific.")},
-		{"John Munro", []byte("Almost before we knew it, we had left the ground.")},
-		{"John Munro", []byte("The sky was cloudless and of a deep dark blue.")},
-		{"John Munro", []byte("The spectacle before us was indeed sublime.")},
-		{"E. E. Smith", []byte("A shining crescent far beneath the flying vessel.")},
-		{"Isaac Asimov", []byte("It was going to be a lonely trip back.")},
-		{"Robert Louis Stevenson", []byte("My two natures had memory in common.")},
-		{"Harry Harrison", []byte("The face of the moon was in shadow.")},
-		{"H. G. Wells", []byte("Then came the night of the first falling star.")},
-	}
-
-	ignoredSampleTexts  map[string][]byte
-	replacedSampleTexts map[string][]byte
-	keysOfSampleTexts   []string
-)
-
-func buildReplacedMapFromKVs(kvs []KV) (kvsmap map[string][]byte) {
-	kvsmap = make(map[string][]byte)
-
-	for _, row := range kvs {
-		if row.Value != nil {
-			kvsmap[row.Key] = row.Value
-		}
-	}
-
-	return kvsmap
-}
-
-func buildIgnoredMapFromKVs(kvs []KV) (kvsmap map[string][]byte) {
-	kvsmap = make(map[string][]byte)
-
-	for _, row := range kvs {
-		if _, ok := kvsmap[row.Key]; !ok && row.Value != nil {
-			kvsmap[row.Key] = row.Value
-		}
-	}
-
-	return kvsmap
-}
-
-func randomDel(kvsmap map[string][]byte) (rkvsmap map[string][]byte, dkeys []string) {
-	knum := len(kvsmap)
-	dnum := knum / 2
-	list := rand.Perm(knum)
-	dmap := make([]bool, knum)
-
-	for index := range dmap {
-		dmap[index] = false
-	}
-
-	for index, iindex := range list {
-		if index < dnum {
-			dmap[iindex] = true
-		}
-	}
-
-	index := 0
-	dkeys = make([]string, 0, dnum)
-	rkvsmap = make(map[string][]byte)
-
-	for k, v := range kvsmap {
-		if dmap[index] {
-			dkeys = append(dkeys, k)
-		} else {
-			rkvsmap[k] = v
-		}
-
-		index++
-	}
-
-	return rkvsmap, dkeys
-}
-
-func testSetup() {
-	// Build datasets for test
-	ignoredSampleTexts = buildIgnoredMapFromKVs(sampleTexts)
-	replacedSampleTexts = buildReplacedMapFromKVs(sampleTexts)
-
-	index := 0
-	keysOfSampleTexts = make([]string, len(replacedSampleTexts))
-
-	for key := range replacedSampleTexts {
-		keysOfSampleTexts[index] = key
-		index++
-	}
-}
-
-func TestMain(m *testing.M) {
-	testSetup()
-	os.Exit(m.Run())
-}
-
-func TestBadDSN(t *testing.T) {
-	// Use bad DSN to open storage
-	if _, err := OpenStorage(os.TempDir(), "test-bad-dsn"); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
-	}
-}
-
-func TestOpenStorage(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	_, err = OpenStorage(fl.Name(), "test-open-storage")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-}
-
-func TestSetValue(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	st, err := OpenStorage(fl.Name(), "test-set-value")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	for _, row := range sampleTexts {
-		if err = st.SetValue(row.Key, row.Value); err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
-		}
-	}
-
-	// Verify values
-	for k, v := range replacedSampleTexts {
-		ov, err := st.GetValue(k)
-
-		if err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
-		}
-
-		if !reflect.DeepEqual(v, ov) {
-			t.Fatalf("Unexpected output result: input = %v, output = %v", v, ov)
-		}
-	}
-}
-
-func TestSetValueIfNotExist(t *testing.T) {
-	// Open storage
-	fl, errTemp := ioutil.TempFile("", "db")
-
-	if errTemp != nil {
-		t.Fatalf("Error occurred: %s", errTemp.Error())
-	}
-
-	st, err := OpenStorage(fl.Name(), "test-set-value-if-not-exist")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	for _, row := range sampleTexts {
-		if err = st.SetValueIfNotExist(row.Key, row.Value); err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
-		}
-	}
-
-	// Verify values
-	for k, v := range ignoredSampleTexts {
-		ov, err := st.GetValue(k)
-
-		if err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
-		}
-
-		if !reflect.DeepEqual(v, ov) {
-			t.Fatalf("Unexpected output result: input = %v, output = %v", v, ov)
-		}
-	}
-}
-
-func TestGetValue(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	st, err := OpenStorage(fl.Name(), "test-get-value")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	for _, row := range sampleTexts {
-		if err = st.SetValue(row.Key, row.Value); err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
-		}
-	}
-
-	// Verify values
-	for k, v := range replacedSampleTexts {
-		ov, err := st.GetValue(k)
-
-		if err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
-		}
-
-		if !reflect.DeepEqual(v, ov) {
-			t.Fatalf("Unexpected output result: input = %v, output = %v", v, ov)
-		}
-	}
-
-	// Test get nil value
-	nonexistentKey := "Jules Verne"
-	v, err := st.GetValue(nonexistentKey)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	if v != nil {
-		t.Fatalf("Unexpected output result: got %v while expecting nil", v)
-	}
-}
-
-func TestDelValue(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	st, err := OpenStorage(fl.Name(), "test-del-value")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	for _, row := range sampleTexts {
-		if err = st.SetValue(row.Key, row.Value); err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
-		}
-	}
-
-	// Verify values
-	for k, v := range replacedSampleTexts {
-		ov, err := st.GetValue(k)
-
-		if err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
-		}
-
-		if !reflect.DeepEqual(v, ov) {
-			t.Fatalf("Unexpected output result: input = %v, output = %v", v, ov)
-		}
-	}
-
-	// Delete value
-	delKey := "Samuel R. Delany"
-	err = st.DelValue(delKey)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Verify nil result
-	v, err := st.GetValue(delKey)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	if v != nil {
-		t.Fatalf("Unexpected output result: got %v while expecting nil", v)
-	}
-
-	// Test deleting a nonexistent key: it should not return any error
-	nonexistentKey := "Jules Verne"
-
-	if err = st.DelValue(nonexistentKey); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-}
-
-func TestSetValues(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	st, err := OpenStorage(fl.Name(), "test-set-values")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	if err = st.SetValues(sampleTexts); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Verify values
-	kvs, err := st.GetValues(keysOfSampleTexts)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	okvs := buildReplacedMapFromKVs(kvs)
-
-	if !reflect.DeepEqual(replacedSampleTexts, okvs) {
-		t.Fatalf("Unexpected output result: input = %v, output = %v", replacedSampleTexts, okvs)
-	}
-}
-
-func TestSetValuesIfNotExist(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	st, err := OpenStorage(fl.Name(), "test-set-values-if-not-exist")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	if err = st.SetValuesIfNotExist(sampleTexts); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
+func newQuery(query string, args ...interface{}) (q Query) {
+	q.Pattern = query
 
-	// Verify values
-	kvs, err := st.GetValues(keysOfSampleTexts)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+	// convert args
+	q.Args = make([]sql.NamedArg, len(args))
+	for i, v := range args {
+		q.Args[i] = sql.Named("", v)
 	}
 
-	okvs := buildIgnoredMapFromKVs(kvs)
-
-	if !reflect.DeepEqual(ignoredSampleTexts, okvs) {
-		t.Fatalf("Unexpected output result: input = %v, output = %v", ignoredSampleTexts, okvs)
-	}
+	return
 }
 
-func TestDelValues(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
+func newNamedQuery(query string, args map[string]interface{}) (q Query) {
+	q.Pattern = query
+	q.Args = make([]sql.NamedArg, len(args))
+	i := 0
 
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+	// convert args
+	for n, v := range args {
+		q.Args[i] = sql.Named(n, v)
+		i++
 	}
 
-	st, err := OpenStorage(fl.Name(), "test-del-values")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	if err = st.SetValues(sampleTexts); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Randomly delete some values
-	rkvs, dkeys := randomDel(replacedSampleTexts)
-
-	if err = st.DelValues(dkeys); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Verify values
-	kvs, err := st.GetValues(keysOfSampleTexts)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	okvs := buildReplacedMapFromKVs(kvs)
-
-	if !reflect.DeepEqual(rkvs, okvs) {
-		t.Fatalf("Unexpected output result: input = %v, output = %v", rkvs, okvs)
-	}
+	return
 }
 
-func TestGetValues(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
+func TestBadType(t *testing.T) {
+	fl, err := ioutil.TempFile("", "sqlite3-")
 
 	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+		t.Fatalf("Error occurred: %v", err)
 	}
 
-	st, err := OpenStorage(fl.Name(), "test-get-values")
+	st, err := New(fmt.Sprintf("file:%s", fl.Name()))
 
 	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+		t.Fatalf("Error occurred: %v", err)
 	}
 
-	// Set values
-	if err = st.SetValues(sampleTexts); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Add some nonexistent keys
-	mixedKeys := append(keysOfSampleTexts, "Jules Verne", "Kathy Tyers", "Jack Vance")
-
-	// Verify values
-	kvs, err := st.GetValues(mixedKeys)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	okvs := buildReplacedMapFromKVs(kvs)
-
-	if !reflect.DeepEqual(replacedSampleTexts, okvs) {
-		t.Fatalf("Unexpected output result: input = %v, output = %v", replacedSampleTexts, okvs)
-	}
-}
-
-func TestSetValuesTx(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	st, err := OpenStorage(fl.Name(), "test-set-values-tx")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	if err = st.SetValuesTx(sampleTexts); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Verify values
-	kvs, err := st.GetValuesTx(keysOfSampleTexts)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	okvs := buildReplacedMapFromKVs(kvs)
-
-	if !reflect.DeepEqual(replacedSampleTexts, okvs) {
-		t.Fatalf("Unexpected output result: input = %v, output = %v", replacedSampleTexts, okvs)
-	}
-}
-
-func TestSetValuesIfNotExistTx(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	st, err := OpenStorage(fl.Name(), "test-set-values-if-not-exist-tx")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	if err = st.SetValuesIfNotExistTx(sampleTexts); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Verify values
-	kvs, err := st.GetValuesTx(keysOfSampleTexts)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	okvs := buildIgnoredMapFromKVs(kvs)
-
-	if !reflect.DeepEqual(ignoredSampleTexts, okvs) {
-		t.Fatalf("Unexpected output result: input = %v, output = %v", ignoredSampleTexts, okvs)
-	}
-}
-
-func TestDelValuesTx(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	st, err := OpenStorage(fl.Name(), "test-del-values-tx")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	if err = st.SetValuesTx(sampleTexts); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Randomly delete some values
-	rkvs, dkeys := randomDel(replacedSampleTexts)
-
-	if err = st.DelValuesTx(dkeys); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Verify values
-	kvs, err := st.GetValuesTx(keysOfSampleTexts)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	okvs := buildReplacedMapFromKVs(kvs)
-
-	if !reflect.DeepEqual(rkvs, okvs) {
-		t.Fatalf("Unexpected output result: input = %v, output = %v", rkvs, okvs)
-	}
-}
-
-func TestGetValuesTx(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	st, err := OpenStorage(fl.Name(), "test-get-values-tx")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	if err = st.SetValuesTx(sampleTexts); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Add some nonexistent keys
-	mixedKeys := append(keysOfSampleTexts, "Jules Verne", "Kathy Tyers", "Jack Vance")
-
-	// Verify values
-	kvs, err := st.GetValuesTx(mixedKeys)
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	okvs := buildReplacedMapFromKVs(kvs)
-
-	if !reflect.DeepEqual(replacedSampleTexts, okvs) {
-		t.Fatalf("Unexpected output result: input = %v, output = %v", replacedSampleTexts, okvs)
-	}
-}
-
-func TestDBError(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	st, err := OpenStorage(fl.Name(), "test-db-error")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Hack the internal structs and filesystem to wipe out the databse
-	if err = st.db.Close(); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	delete(index.db, fl.Name())
-
-	if err = os.Truncate(fl.Name(), 0); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	if st.db, err = openDB(fl.Name()); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Now try some operations opon it
-	if err = st.SetValue("", nil); err == nil {
+	if err = st.Prepare(context.Background(), struct{}{}); err == nil {
 		t.Fatal("Unexpected result: returned nil while expecting an error")
 	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+		t.Logf("Error occurred as expected: %v", err)
 	}
 
-	if err = st.SetValues(sampleTexts); err == nil {
+	if _, err = st.Commit(context.Background(), struct{}{}); err == nil {
 		t.Fatal("Unexpected result: returned nil while expecting an error")
 	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+		t.Logf("Error occurred as expected: %v", err)
 	}
 
-	if err = st.SetValuesTx(sampleTexts); err == nil {
+	if err = st.Rollback(context.Background(), struct{}{}); err == nil {
 		t.Fatal("Unexpected result: returned nil while expecting an error")
 	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+		t.Logf("Error occurred as expected: %v", err)
 	}
+}
 
-	if err = st.SetValueIfNotExist("", nil); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
-	}
+func TestStorage(t *testing.T) {
+	fl, err := ioutil.TempFile("", "sqlite3-")
 
-	if err = st.SetValuesIfNotExist(sampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
 	}
 
-	if err = st.SetValuesIfNotExistTx(sampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
-	}
+	st, err := New(fmt.Sprintf("file:%s", fl.Name()))
 
-	if err = st.DelValue(""); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
 	}
 
-	if err = st.DelValues(keysOfSampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+	el1 := &ExecLog{
+		ConnectionID: 1,
+		SeqNo:        1,
+		Timestamp:    time.Now().UnixNano(),
+		Queries: []Query{
+			newQuery("CREATE TABLE IF NOT EXISTS `kv` (`key` TEXT PRIMARY KEY, `value` BLOB)"),
+			newQuery("INSERT OR IGNORE INTO `kv` VALUES ('k0', NULL)"),
+			newQuery("INSERT OR IGNORE INTO `kv` VALUES ('k1', 'v1')"),
+			newQuery("INSERT OR IGNORE INTO `kv` VALUES ('k2', 'v2')"),
+			newQuery("INSERT OR IGNORE INTO `kv` VALUES ('k3', 'v3')"),
+			newQuery("INSERT OR REPLACE INTO `kv` VALUES ('k3', 'v3-2')"),
+			newQuery("DELETE FROM `kv` WHERE `key`='k2'"),
+		},
 	}
 
-	if err = st.DelValuesTx(keysOfSampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+	el2 := &ExecLog{
+		ConnectionID: 1,
+		SeqNo:        2,
+		Timestamp:    time.Now().UnixNano(),
+		Queries: []Query{
+			newQuery("INSERT OR REPLACE INTO `kv` VALUES ('k1', 'v1-2')"),
+		},
 	}
 
-	if _, err = st.GetValue(""); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+	if err = st.Prepare(context.Background(), el1); err != nil {
+		t.Fatalf("Error occurred: %v", err)
 	}
 
-	if _, err = st.GetValues(keysOfSampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+	if err = st.Prepare(context.Background(), el1); err != nil {
+		t.Fatalf("Error occurred: %v", err)
 	}
 
-	if _, err = st.GetValuesTx(keysOfSampleTexts); err == nil {
+	if err = st.Prepare(context.Background(), el2); err == nil {
 		t.Fatal("Unexpected result: returned nil while expecting an error")
 	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+		t.Logf("Error occurred as expected: %v", err)
 	}
 
-	// Hack the internal structs to close the database
-	if err = st.db.Close(); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	delete(index.db, fl.Name())
-
-	// Now try some operations opon it
-	if err = st.SetValue("", nil); err == nil {
+	if _, err = st.Commit(context.Background(), el2); err == nil {
 		t.Fatal("Unexpected result: returned nil while expecting an error")
 	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+		t.Logf("Error occurred as expected: %v", err)
 	}
 
-	if err = st.SetValues(sampleTexts); err == nil {
+	if err = st.Rollback(context.Background(), el2); err == nil {
 		t.Fatal("Unexpected result: returned nil while expecting an error")
 	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+		t.Logf("Error occurred as expected: %v", err)
 	}
 
-	if err = st.SetValuesTx(sampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
+	var res interface{}
+	if res, err = st.Commit(context.Background(), el1); err != nil {
+		t.Fatalf("Error occurred: %v", err)
 	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+		result := res.(ExecResult)
+		t.Logf("Result: %v", result)
 	}
 
-	if err = st.SetValueIfNotExist("", nil); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
-	}
+	// test query
+	columns, types, data, err := st.Query(context.Background(),
+		[]Query{newQuery("SELECT * FROM `kv` ORDER BY `key` ASC")})
 
-	if err = st.SetValuesIfNotExist(sampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
-	}
-
-	if err = st.SetValuesIfNotExistTx(sampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+	if err != nil {
+		t.Fatalf("Query failed: %v", err.Error())
 	}
-
-	if err = st.DelValue(""); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+	if !reflect.DeepEqual(columns, []string{"key", "value"}) {
+		t.Fatalf("Error column result: %v", columns)
 	}
-
-	if err = st.DelValues(keysOfSampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
+	if !reflect.DeepEqual(types, []string{"TEXT", "BLOB"}) {
+		t.Fatalf("Error types result: %v", types)
 	}
-
-	if err = st.DelValuesTx(keysOfSampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
+	if len(data) != 3 {
+		t.Fatalf("Error result count: %v, should be 3", len(data))
 	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
-	}
-
-	if _, err = st.GetValue(""); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
-	}
-
-	if _, err = st.GetValues(keysOfSampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	} else {
-		t.Logf("Error occurred as expected: %s", err.Error())
-	}
-
-	if _, err = st.GetValuesTx(keysOfSampleTexts); err == nil {
-		t.Fatal("Unexpected result: returned nil while expecting an error")
-	}
-}
-
-func TestDataPersistence(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-	dsn := fmt.Sprintf("file:%s", fl.Name())
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	st, err := OpenStorage(dsn, "test-data-persistence")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	for _, row := range sampleTexts {
-		if err = st.SetValue(row.Key, row.Value); err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
+		// compare rows
+		should1 := []interface{}{[]byte("k0"), nil}
+		should2 := []interface{}{[]byte("k1"), []byte("v1")}
+		should3 := []interface{}{[]byte("k3"), []byte("v3-2")}
+		t.Logf("Rows: %v", data)
+		if !reflect.DeepEqual(data[0], should1) {
+			t.Fatalf("Error result row: %v, should: %v", data[0], should1)
 		}
-	}
-
-	// Verify values
-	for k, v := range replacedSampleTexts {
-		ov, err := st.GetValue(k)
-
-		if err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
+		if !reflect.DeepEqual(data[1], should2) {
+			t.Fatalf("Error result row: %v, should: %v", data[1], should2)
 		}
-
-		if !reflect.DeepEqual(v, ov) {
-			t.Fatalf("Unexpected output result: input = %v, output = %v", v, ov)
+		if !reflect.DeepEqual(data[2], should3) {
+			t.Fatalf("Error result row: %v, should: %v", data[2], should2)
 		}
 	}
 
-	// Hack the internal structs to close the database
-	if err = st.db.Close(); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	delete(index.db, dsn)
-
-	// Now reopen the storage and verify the data
-	st, err = OpenStorage(dsn, "test-data-persistence")
+	// test query with projection
+	columns, types, data, err = st.Query(context.Background(),
+		[]Query{newQuery("SELECT `key` FROM `kv` ORDER BY `key` ASC")})
 
 	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+		t.Fatalf("Query failed: %v", err.Error())
 	}
-
-	content, _ := ioutil.ReadFile(fl.Name())
-	if !bytes.Contains(content, []byte(sampleTexts[0].Key)) {
-		t.Fatal("db is corrupted")
+	if !reflect.DeepEqual(columns, []string{"key"}) {
+		t.Fatalf("Error column result: %v", columns)
 	}
-
-	for k, v := range replacedSampleTexts {
-		ov, err := st.GetValue(k)
-
-		if err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
-		}
-
-		if !reflect.DeepEqual(v, ov) {
-			t.Fatalf("Unexpected output result: input = %v, output = %v", v, ov)
-		}
-	}
-}
-
-func TestCipherDBDataPersistence(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
-	dsn := fmt.Sprintf("file:%s?_crypto_key=auxten", fl.Name())
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+	if !reflect.DeepEqual(types, []string{"TEXT"}) {
+		t.Fatalf("Error types result: %v", types)
 	}
-
-	st, err := OpenStorage(dsn, "test-data-persistence")
-
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	// Set values
-	for _, row := range sampleTexts {
-		if err = st.SetValue(row.Key, row.Value); err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
+	if len(data) != 3 {
+		t.Fatalf("Error result count: %v, should be 3", len(data))
+	} else {
+		// compare rows
+		should1 := []interface{}{[]byte("k0")}
+		should2 := []interface{}{[]byte("k1")}
+		should3 := []interface{}{[]byte("k3")}
+		t.Logf("Rows: %v", data)
+		if !reflect.DeepEqual(data[0], should1) {
+			t.Fatalf("Error result row: %v, should: %v", data[0], should1)
 		}
-	}
-
-	// Verify values
-	for k, v := range replacedSampleTexts {
-		ov, err := st.GetValue(k)
-
-		if err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
+		if !reflect.DeepEqual(data[1], should2) {
+			t.Fatalf("Error result row: %v, should: %v", data[1], should2)
 		}
-
-		if !reflect.DeepEqual(v, ov) {
-			t.Fatalf("Unexpected output result: input = %v, output = %v", v, ov)
+		if !reflect.DeepEqual(data[2], should3) {
+			t.Fatalf("Error result row: %v, should: %v", data[2], should2)
 		}
 	}
 
-	// Hack the internal structs to close the database
-	if err = st.db.Close(); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
-	}
-
-	delete(index.db, dsn)
-
-	// Now reopen the storage and verify the data
-	st, err = OpenStorage(dsn, "test-data-persistence")
+	// test query with condition
+	columns, types, data, err = st.Query(context.Background(),
+		[]Query{newQuery("SELECT `key` FROM `kv` WHERE `value` IS NOT NULL ORDER BY `key` ASC")})
 
 	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+		t.Fatalf("Query failed: %v", err.Error())
 	}
-
-	content, _ := ioutil.ReadFile(fl.Name())
-	if bytes.Contains(content, []byte(sampleTexts[0].Key)) {
-		t.Fatal("db not ciphered")
+	if !reflect.DeepEqual(columns, []string{"key"}) {
+		t.Fatalf("Error column result: %v", columns)
 	}
-
-	for k, v := range replacedSampleTexts {
-		ov, err := st.GetValue(k)
-
-		if err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
-		}
-
-		if !reflect.DeepEqual(v, ov) {
-			t.Fatalf("Unexpected output result: input = %v, output = %v", v, ov)
-		}
+	if !reflect.DeepEqual(types, []string{"TEXT"}) {
+		t.Fatalf("Error types result: %v", types)
 	}
-}
-
-func randomSleep() {
-	r := rand.Intn(10)
-	time.Sleep(time.Duration(r) * time.Millisecond)
-}
-
-func randomGetValue(wg *sync.WaitGroup, st *Storage, t *testing.T) {
-	defer wg.Done()
-
-	for i := 0; i < 1000; i++ {
-		randomSleep()
-		key := keysOfSampleTexts[rand.Intn(len(keysOfSampleTexts))]
-		value := replacedSampleTexts[key]
-
-		if ov, err := st.GetValue(key); err != nil {
-			t.Fatalf("Error occurred: %s", err.Error())
-		} else if !reflect.DeepEqual(value, ov) {
-			t.Fatalf("Unexpected output result: input = %v, output = %v", value, ov)
+	if len(data) != 2 {
+		t.Fatalf("Error result count: %v, should be 3", len(data))
+	} else {
+		// compare rows
+		should1 := []interface{}{[]byte("k1")}
+		should2 := []interface{}{[]byte("k3")}
+		t.Logf("Rows: %v", data)
+		if !reflect.DeepEqual(data[0], should1) {
+			t.Fatalf("Error result row: %v, should: %v", data[0], should1)
+		}
+		if !reflect.DeepEqual(data[1], should2) {
+			t.Fatalf("Error result row: %v, should: %v", data[1], should2)
 		}
 	}
-}
 
-func TestConcurrency(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
+	// test failed query
+	columns, types, data, err = st.Query(context.Background(), []Query{newQuery("SQL???? WHAT!!!!")})
 
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+	if err == nil {
+		t.Fatal("Query should failed")
+	} else {
+		t.Logf("Query failed as expected with: %v", err.Error())
 	}
 
-	st, err := OpenStorage(fl.Name(), "test-data-persistence")
+	// test non-read query
+	columns, types, data, err = st.Query(context.Background(),
+		[]Query{newQuery("DELETE FROM `kv` WHERE `value` IS NULL")})
 
-	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+	execResult, err := st.Exec(context.Background(),
+		[]Query{newQuery("INSERT OR REPLACE INTO `kv` VALUES ('k4', 'v4')")})
+	if err != nil || execResult.RowsAffected != 1 {
+		t.Fatalf("Exec INSERT failed: %v", err)
 	}
-
-	// Set values
-	if err = st.SetValuesTx(sampleTexts); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+	// test with arguments
+	execResult, err = st.Exec(context.Background(), []Query{newQuery("DELETE FROM `kv` WHERE `key`='k4'")})
+	if err != nil || execResult.RowsAffected != 1 {
+		t.Fatalf("Exec DELETE failed: %v", err)
 	}
-
-	// Run concurrent GetValue
-	var wg sync.WaitGroup
-
-	for i := 0; i < 10; i++ {
-		wg.Add(1)
-		go randomGetValue(&wg, st, t)
+	execResult, err = st.Exec(context.Background(),
+		[]Query{newQuery("DELETE FROM `kv` WHERE `key`=?", "not_exist")})
+	if err != nil || execResult.RowsAffected != 0 {
+		t.Fatalf("Exec DELETE failed: %v", err)
 	}
 
-	wg.Wait()
-}
-
-func TestCipherDBConcurrency(t *testing.T) {
-	// Open storage
-	fl, err := ioutil.TempFile("", "db")
+	// test again
+	columns, types, data, err = st.Query(context.Background(), []Query{newQuery("SELECT `key` FROM `kv`")})
 	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+		t.Fatalf("Query failed: %v", err.Error())
+	} else if len(data) != 3 {
+		t.Fatalf("Last write query should not take any effect, row count: %v", len(data))
+	} else {
+		t.Logf("Rows: %v", data)
 	}
-	dsn := fmt.Sprintf("file:%s?_crypto_key=auxten", fl.Name())
-
-	st, err := OpenStorage(dsn, "test-data-persistence")
 
+	// test with select
+	columns, types, data, err = st.Query(context.Background(),
+		[]Query{newQuery("SELECT `key` FROM `kv` WHERE `key` IN (?)", "k1")})
 	if err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+		t.Fatalf("Query failed: %v", err.Error())
+	} else if len(data) != 1 {
+		t.Fatalf("Should only have one record, but actually %v", len(data))
+	} else {
+		t.Logf("Rows: %v", data)
 	}
 
-	// Set values
-	if err = st.SetValuesTx(sampleTexts); err != nil {
-		t.Fatalf("Error occurred: %s", err.Error())
+	// test with select with named arguments
+	columns, types, data, err = st.Query(context.Background(),
+		[]Query{newNamedQuery("SELECT `key` FROM `kv` WHERE `key` IN (:test2, :test1)", map[string]interface{}{
+			"test1": "k1",
+			"test2": "k3",
+		})})
+	if err != nil {
+		t.Fatalf("Query failed: %v", err.Error())
+	} else if len(data) != 2 {
+		t.Fatalf("Should only have two records, but actually %v", len(data))
+	} else {
+		t.Logf("Rows: %v", data)
 	}
 
-	// Run concurrent GetValue
-	var wg sync.WaitGroup
-
-	for i := 0; i < 10; i++ {
-		wg.Add(1)
-		go randomGetValue(&wg, st, t)
+	// test with function
+	columns, types, data, err = st.Query(context.Background(),
+		[]Query{newQuery("SELECT COUNT(1) AS `c` FROM `kv`")})
+	if err != nil {
+		t.Fatalf("Query failed: %v", err.Error())
+	} else {
+		if len(columns) != 1 {
+			t.Fatalf("Query result should contain only one column, now %v", len(columns))
+		} else if columns[0] != "c" {
+			t.Fatalf("Query result column name is not defined alias, but :%v", columns[0])
+		}
+		if len(types) != 1 {
+			t.Fatalf("Query result should contain only one column, now %v", len(types))
+		} else {
+			t.Logf("Query result type is: %v", types[0])
+		}
+		if len(data) != 1 || len(data[0]) != 1 {
+			t.Fatalf("Query result should contain only one row and one column, now %v", data)
+		} else if !reflect.DeepEqual(data[0][0], int64(3)) {
+			t.Fatalf("Query result should be table row count 3, but: %v", data[0])
+		}
 	}
 
-	wg.Wait()
-
-	content, _ := ioutil.ReadFile(fl.Name())
-	if bytes.Contains(content, []byte(sampleTexts[0].Key)) {
-		t.Fatal("db not ciphered")
+	// test with timestamp fields
+	_, err = st.Exec(context.Background(), []Query{
+		newQuery("CREATE TABLE `tm` (tm TIMESTAMP)"),
+		newQuery("INSERT INTO `tm` VALUES(DATE('NOW'))"),
+	})
+	if err != nil {
+		t.Fatalf("Query failed: %v", err.Error())
+	} else {
+		// query for values
+		_, _, data, err = st.Query(context.Background(), []Query{newQuery("SELECT `tm` FROM `tm`")})
+		if len(data) != 1 || len(data[0]) != 1 {
+			t.Fatalf("Query result should contain only one row and one column, now %v", data)
+		} else if !reflect.TypeOf(data[0][0]).AssignableTo(reflect.TypeOf(time.Time{})) {
+			t.Fatalf("Query result should be time.Time type, but: %v", reflect.TypeOf(data[0][0]).String())
+		}
 	}
 }
diff --git a/test/GNTE/GNTE b/test/GNTE/GNTE
index 51de88917..93e48d707 160000
--- a/test/GNTE/GNTE
+++ b/test/GNTE/GNTE
@@ -1 +1 @@
-Subproject commit 51de889172de377ec104900b9566ef8c8510525e
+Subproject commit 93e48d7072b002c3d070f9b712ff22b53c65c6b3
diff --git a/test/GNTE/conf/node_miner_10.250.100.2/config.yaml b/test/GNTE/conf/node_miner_10.250.100.2/config.yaml
index 97cb6d3a4..2a301d150 100644
--- a/test/GNTE/conf/node_miner_10.250.100.2/config.yaml
+++ b/test/GNTE/conf/node_miner_10.250.100.2/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "60s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/GNTE/conf/node_miner_10.250.100.3/config.yaml b/test/GNTE/conf/node_miner_10.250.100.3/config.yaml
index af65305fa..1106c28bb 100644
--- a/test/GNTE/conf/node_miner_10.250.100.3/config.yaml
+++ b/test/GNTE/conf/node_miner_10.250.100.3/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "60s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/GNTE/conf/node_miner_10.250.100.4/config.yaml b/test/GNTE/conf/node_miner_10.250.100.4/config.yaml
index 1b829fb70..b19dace89 100644
--- a/test/GNTE/conf/node_miner_10.250.100.4/config.yaml
+++ b/test/GNTE/conf/node_miner_10.250.100.4/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "60s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/GNTE/conf/node_miner_10.250.100.5/config.yaml b/test/GNTE/conf/node_miner_10.250.100.5/config.yaml
index 810af9a5f..a09d83606 100755
--- a/test/GNTE/conf/node_miner_10.250.100.5/config.yaml
+++ b/test/GNTE/conf/node_miner_10.250.100.5/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "60s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/GNTE/conf/node_miner_10.250.100.6/config.yaml b/test/GNTE/conf/node_miner_10.250.100.6/config.yaml
index 7e07f7965..b96505d19 100755
--- a/test/GNTE/conf/node_miner_10.250.100.6/config.yaml
+++ b/test/GNTE/conf/node_miner_10.250.100.6/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "60s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/GNTE/conf/node_miner_10.250.100.7/config.yaml b/test/GNTE/conf/node_miner_10.250.100.7/config.yaml
index 3b60c4402..5370e24f6 100755
--- a/test/GNTE/conf/node_miner_10.250.100.7/config.yaml
+++ b/test/GNTE/conf/node_miner_10.250.100.7/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "60s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/GNTE/conf/node_miner_10.250.100.8/config.yaml b/test/GNTE/conf/node_miner_10.250.100.8/config.yaml
index d81332473..bc633a6fc 100755
--- a/test/GNTE/conf/node_miner_10.250.100.8/config.yaml
+++ b/test/GNTE/conf/node_miner_10.250.100.8/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "60s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/GNTE/conf/node_miner_10.250.100.9/config.yaml b/test/GNTE/conf/node_miner_10.250.100.9/config.yaml
index 6ca3fae99..887064529 100755
--- a/test/GNTE/conf/node_miner_10.250.100.9/config.yaml
+++ b/test/GNTE/conf/node_miner_10.250.100.9/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "60s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/fuse/node_0/config.yaml b/test/fuse/node_0/config.yaml
new file mode 100644
index 000000000..9919e977e
--- /dev/null
+++ b/test/fuse/node_0/config.yaml
@@ -0,0 +1,99 @@
+IsTestMode: true
+WorkingRoot: "./"
+PubKeyStoreFile: "public.keystore"
+PrivateKeyFile: "private.key"
+DHTFileName: "dht.db"
+ListenAddr: "127.0.0.1:6122"
+ThisNodeID: "00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9"
+ValidDNSKeys:
+  koPbw9wmYZ7ggcjnQ6ayHyhHaDNMYELKTqT+qRGrZpWSccr/lBcrm10Z1PuQHB3Azhii+sb0PYFkH1ruxLhe5g==: cloudflare.com
+  mdsswUyr3DPW132mOi8V9xESWE8jTo0dxCjjnopKl+GqJxpVXckHAeF+KkxLbxILfDLUT0rAK9iUzy1L53eKGQ==: cloudflare.com
+MinNodeIDDifficulty: 2
+DNSSeed:
+  EnforcedDNSSEC: false
+  DNSServers:
+  - 1.1.1.1
+  - 202.46.34.74
+  - 202.46.34.75
+  - 202.46.34.76
+
+BlockProducer:
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  NodeID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  ChainFileName: "chain.db"
+  BPGenesisInfo:
+    Version: 1
+    BlockHash: f745ca6427237aac858dd3c7f2df8e6f3c18d0f1c164e07a1c6b8eebeba6b154
+    Producer: 0000000000000000000000000000000000000000000000000000000000000001
+    MerkleRoot: 0000000000000000000000000000000000000000000000000000000000000001
+    ParentHash: 0000000000000000000000000000000000000000000000000000000000000001
+    Timestamp: 2018-08-13T21:59:59.12Z
+KnownNodes:
+- ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  Addr: 127.0.0.1:6122
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Leader
+- ID: 00000381d46fd6cf7742d7fb94e2422033af989c0e348b5781b3219599a3af35
+  Nonce:
+    a: 478373
+    b: 0
+    c: 0
+    d: 2305843009893772025
+  Addr: 127.0.0.1:6121
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 000000172580063ded88e010556b0aca2851265be8845b1ef397e8fce6ab5582
+  Nonce:
+    a: 259939
+    b: 0
+    c: 0
+    d: 2305843012544226372
+  Addr: 127.0.0.1:6120
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 00000f3b43288fe99831eb533ab77ec455d13e11fc38ec35a42d4edd17aa320d
+  Nonce:
+    a: 22403
+    b: 0
+    c: 0
+    d: 0
+  Addr: ""
+  PublicKey: 02ec784ca599f21ef93fe7abdc68d78817ab6c9b31f2324d15ea174d9da498b4c4
+  Role: Client
+- ID: 000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade
+  Nonce:
+    a: 567323
+    b: 0
+    c: 0
+    d: 3104982049
+  Addr: 127.0.0.1:3144
+  PublicKey: 0367aa51809a7c1dc0f82c02452fec9557b3e1d10ce7c919d8e73d90048df86d20
+  Role: Miner
+- ID: 000005f4f22c06f76c43c4f48d5a7ec1309cc94030cbf9ebae814172884ac8b5
+  Nonce:
+    a: 240524
+    b: 0
+    c: 0
+    d: 2305843010430351476
+  Addr: 127.0.0.1:3145
+  PublicKey: 02914bca0806f040dd842207c44474ab41ecd29deee7f2d355789c5c78d448ca16
+  Role: Miner
+- ID: 000003f49592f83d0473bddb70d543f1096b4ffed5e5f942a3117e256b7052b8
+  Nonce:
+    a: 606016
+    b: 0
+    c: 0
+    d: 13835058056920509601
+  Addr: 127.0.0.1:3146
+  PublicKey: 03ae859eac5b72ee428c7a85f10b2ce748d9de5e480aefbb70f6597dfa8b2175e5
+  Role: Miner
diff --git a/test/fuse/node_0/private.key b/test/fuse/node_0/private.key
new file mode 100644
index 000000000..449618c0a
--- /dev/null
+++ b/test/fuse/node_0/private.key
@@ -0,0 +1,2 @@
+WAð�8��#|�T��Z�ԓ�`�mF�}�~�e��ʆ?�~�����*E��%���v�����p�o*a߂�ç_Bľ@8
+��M�C2�
\ No newline at end of file
diff --git a/test/fuse/node_1/config.yaml b/test/fuse/node_1/config.yaml
new file mode 100644
index 000000000..caaa118d5
--- /dev/null
+++ b/test/fuse/node_1/config.yaml
@@ -0,0 +1,99 @@
+IsTestMode: true
+WorkingRoot: "./"
+PubKeyStoreFile: "public.keystore"
+PrivateKeyFile: "private.key"
+DHTFileName: "dht.db"
+ListenAddr: "127.0.0.1:6121"
+ThisNodeID: "00000381d46fd6cf7742d7fb94e2422033af989c0e348b5781b3219599a3af35"
+ValidDNSKeys:
+  koPbw9wmYZ7ggcjnQ6ayHyhHaDNMYELKTqT+qRGrZpWSccr/lBcrm10Z1PuQHB3Azhii+sb0PYFkH1ruxLhe5g==: cloudflare.com
+  mdsswUyr3DPW132mOi8V9xESWE8jTo0dxCjjnopKl+GqJxpVXckHAeF+KkxLbxILfDLUT0rAK9iUzy1L53eKGQ==: cloudflare.com
+MinNodeIDDifficulty: 2
+DNSSeed:
+  EnforcedDNSSEC: false
+  DNSServers:
+  - 1.1.1.1
+  - 202.46.34.74
+  - 202.46.34.75
+  - 202.46.34.76
+
+BlockProducer:
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  NodeID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  ChainFileName: "chain.db"
+  BPGenesisInfo:
+    Version: 1
+    BlockHash: f745ca6427237aac858dd3c7f2df8e6f3c18d0f1c164e07a1c6b8eebeba6b154
+    Producer: 0000000000000000000000000000000000000000000000000000000000000001
+    MerkleRoot: 0000000000000000000000000000000000000000000000000000000000000001
+    ParentHash: 0000000000000000000000000000000000000000000000000000000000000001
+    Timestamp: 2018-08-13T21:59:59.12Z
+KnownNodes:
+- ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  Addr: 127.0.0.1:6122
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Leader
+- ID: 00000381d46fd6cf7742d7fb94e2422033af989c0e348b5781b3219599a3af35
+  Nonce:
+    a: 478373
+    b: 0
+    c: 0
+    d: 2305843009893772025
+  Addr: 127.0.0.1:6121
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 000000172580063ded88e010556b0aca2851265be8845b1ef397e8fce6ab5582
+  Nonce:
+    a: 259939
+    b: 0
+    c: 0
+    d: 2305843012544226372
+  Addr: 127.0.0.1:6120
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 00000f3b43288fe99831eb533ab77ec455d13e11fc38ec35a42d4edd17aa320d
+  Nonce:
+    a: 22403
+    b: 0
+    c: 0
+    d: 0
+  Addr: ""
+  PublicKey: 02ec784ca599f21ef93fe7abdc68d78817ab6c9b31f2324d15ea174d9da498b4c4
+  Role: Client
+- ID: 000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade
+  Nonce:
+    a: 567323
+    b: 0
+    c: 0
+    d: 3104982049
+  Addr: 127.0.0.1:3144
+  PublicKey: 0367aa51809a7c1dc0f82c02452fec9557b3e1d10ce7c919d8e73d90048df86d20
+  Role: Miner
+- ID: 000005f4f22c06f76c43c4f48d5a7ec1309cc94030cbf9ebae814172884ac8b5
+  Nonce:
+    a: 240524
+    b: 0
+    c: 0
+    d: 2305843010430351476
+  Addr: 127.0.0.1:3145
+  PublicKey: 02914bca0806f040dd842207c44474ab41ecd29deee7f2d355789c5c78d448ca16
+  Role: Miner
+- ID: 000003f49592f83d0473bddb70d543f1096b4ffed5e5f942a3117e256b7052b8
+  Nonce:
+    a: 606016
+    b: 0
+    c: 0
+    d: 13835058056920509601
+  Addr: 127.0.0.1:3146
+  PublicKey: 03ae859eac5b72ee428c7a85f10b2ce748d9de5e480aefbb70f6597dfa8b2175e5
+  Role: Miner
diff --git a/test/fuse/node_1/private.key b/test/fuse/node_1/private.key
new file mode 100644
index 000000000..449618c0a
--- /dev/null
+++ b/test/fuse/node_1/private.key
@@ -0,0 +1,2 @@
+WAð�8��#|�T��Z�ԓ�`�mF�}�~�e��ʆ?�~�����*E��%���v�����p�o*a߂�ç_Bľ@8
+��M�C2�
\ No newline at end of file
diff --git a/test/fuse/node_2/config.yaml b/test/fuse/node_2/config.yaml
new file mode 100644
index 000000000..18c3409d0
--- /dev/null
+++ b/test/fuse/node_2/config.yaml
@@ -0,0 +1,99 @@
+IsTestMode: true
+WorkingRoot: "./"
+PubKeyStoreFile: "public.keystore"
+PrivateKeyFile: "private.key"
+DHTFileName: "dht.db"
+ListenAddr: "127.0.0.1:6120"
+ThisNodeID: "000000172580063ded88e010556b0aca2851265be8845b1ef397e8fce6ab5582"
+ValidDNSKeys:
+  koPbw9wmYZ7ggcjnQ6ayHyhHaDNMYELKTqT+qRGrZpWSccr/lBcrm10Z1PuQHB3Azhii+sb0PYFkH1ruxLhe5g==: cloudflare.com
+  mdsswUyr3DPW132mOi8V9xESWE8jTo0dxCjjnopKl+GqJxpVXckHAeF+KkxLbxILfDLUT0rAK9iUzy1L53eKGQ==: cloudflare.com
+MinNodeIDDifficulty: 2
+DNSSeed:
+  EnforcedDNSSEC: false
+  DNSServers:
+  - 1.1.1.1
+  - 202.46.34.74
+  - 202.46.34.75
+  - 202.46.34.76
+
+BlockProducer:
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  NodeID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  ChainFileName: "chain.db"
+  BPGenesisInfo:
+    Version: 1
+    BlockHash: f745ca6427237aac858dd3c7f2df8e6f3c18d0f1c164e07a1c6b8eebeba6b154
+    Producer: 0000000000000000000000000000000000000000000000000000000000000001
+    MerkleRoot: 0000000000000000000000000000000000000000000000000000000000000001
+    ParentHash: 0000000000000000000000000000000000000000000000000000000000000001
+    Timestamp: 2018-08-13T21:59:59.12Z
+KnownNodes:
+- ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  Addr: 127.0.0.1:6122
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Leader
+- ID: 00000381d46fd6cf7742d7fb94e2422033af989c0e348b5781b3219599a3af35
+  Nonce:
+    a: 478373
+    b: 0
+    c: 0
+    d: 2305843009893772025
+  Addr: 127.0.0.1:6121
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 000000172580063ded88e010556b0aca2851265be8845b1ef397e8fce6ab5582
+  Nonce:
+    a: 259939
+    b: 0
+    c: 0
+    d: 2305843012544226372
+  Addr: 127.0.0.1:6120
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 00000f3b43288fe99831eb533ab77ec455d13e11fc38ec35a42d4edd17aa320d
+  Nonce:
+    a: 22403
+    b: 0
+    c: 0
+    d: 0
+  Addr: ""
+  PublicKey: 02ec784ca599f21ef93fe7abdc68d78817ab6c9b31f2324d15ea174d9da498b4c4
+  Role: Client
+- ID: 000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade
+  Nonce:
+    a: 567323
+    b: 0
+    c: 0
+    d: 3104982049
+  Addr: 127.0.0.1:3144
+  PublicKey: 0367aa51809a7c1dc0f82c02452fec9557b3e1d10ce7c919d8e73d90048df86d20
+  Role: Miner
+- ID: 000005f4f22c06f76c43c4f48d5a7ec1309cc94030cbf9ebae814172884ac8b5
+  Nonce:
+    a: 240524
+    b: 0
+    c: 0
+    d: 2305843010430351476
+  Addr: 127.0.0.1:3145
+  PublicKey: 02914bca0806f040dd842207c44474ab41ecd29deee7f2d355789c5c78d448ca16
+  Role: Miner
+- ID: 000003f49592f83d0473bddb70d543f1096b4ffed5e5f942a3117e256b7052b8
+  Nonce:
+    a: 606016
+    b: 0
+    c: 0
+    d: 13835058056920509601
+  Addr: 127.0.0.1:3146
+  PublicKey: 03ae859eac5b72ee428c7a85f10b2ce748d9de5e480aefbb70f6597dfa8b2175e5
+  Role: Miner
diff --git a/test/fuse/node_2/private.key b/test/fuse/node_2/private.key
new file mode 100644
index 000000000..449618c0a
--- /dev/null
+++ b/test/fuse/node_2/private.key
@@ -0,0 +1,2 @@
+WAð�8��#|�T��Z�ԓ�`�mF�}�~�e��ʆ?�~�����*E��%���v�����p�o*a߂�ç_Bľ@8
+��M�C2�
\ No newline at end of file
diff --git a/test/fuse/node_c/config.yaml b/test/fuse/node_c/config.yaml
new file mode 100644
index 000000000..d90eca3fe
--- /dev/null
+++ b/test/fuse/node_c/config.yaml
@@ -0,0 +1,99 @@
+IsTestMode: true
+WorkingRoot: "./"
+PubKeyStoreFile: "public.keystore"
+PrivateKeyFile: "private.key"
+DHTFileName: "dht.db"
+ListenAddr: "127.0.0.1:6120"
+ThisNodeID: "00000f3b43288fe99831eb533ab77ec455d13e11fc38ec35a42d4edd17aa320d"
+ValidDNSKeys:
+  koPbw9wmYZ7ggcjnQ6ayHyhHaDNMYELKTqT+qRGrZpWSccr/lBcrm10Z1PuQHB3Azhii+sb0PYFkH1ruxLhe5g==: cloudflare.com
+  mdsswUyr3DPW132mOi8V9xESWE8jTo0dxCjjnopKl+GqJxpVXckHAeF+KkxLbxILfDLUT0rAK9iUzy1L53eKGQ==: cloudflare.com
+MinNodeIDDifficulty: 2
+DNSSeed:
+  EnforcedDNSSEC: false
+  DNSServers:
+  - 1.1.1.1
+  - 202.46.34.74
+  - 202.46.34.75
+  - 202.46.34.76
+
+BlockProducer:
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  NodeID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  ChainFileName: "chain.db"
+  BPGenesisInfo:
+    Version: 1
+    BlockHash: f745ca6427237aac858dd3c7f2df8e6f3c18d0f1c164e07a1c6b8eebeba6b154
+    Producer: 0000000000000000000000000000000000000000000000000000000000000001
+    MerkleRoot: 0000000000000000000000000000000000000000000000000000000000000001
+    ParentHash: 0000000000000000000000000000000000000000000000000000000000000001
+    Timestamp: 2018-08-13T21:59:59.12Z
+KnownNodes:
+- ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  Addr: 127.0.0.1:6122
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Leader
+- ID: 00000381d46fd6cf7742d7fb94e2422033af989c0e348b5781b3219599a3af35
+  Nonce:
+    a: 478373
+    b: 0
+    c: 0
+    d: 2305843009893772025
+  Addr: 127.0.0.1:6121
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 000000172580063ded88e010556b0aca2851265be8845b1ef397e8fce6ab5582
+  Nonce:
+    a: 259939
+    b: 0
+    c: 0
+    d: 2305843012544226372
+  Addr: 127.0.0.1:6120
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 00000f3b43288fe99831eb533ab77ec455d13e11fc38ec35a42d4edd17aa320d
+  Nonce:
+    a: 22403
+    b: 0
+    c: 0
+    d: 0
+  Addr: ""
+  PublicKey: 02ec784ca599f21ef93fe7abdc68d78817ab6c9b31f2324d15ea174d9da498b4c4
+  Role: Client
+- ID: 000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade
+  Nonce:
+    a: 567323
+    b: 0
+    c: 0
+    d: 3104982049
+  Addr: 127.0.0.1:3144
+  PublicKey: 0367aa51809a7c1dc0f82c02452fec9557b3e1d10ce7c919d8e73d90048df86d20
+  Role: Miner
+- ID: 000005f4f22c06f76c43c4f48d5a7ec1309cc94030cbf9ebae814172884ac8b5
+  Nonce:
+    a: 240524
+    b: 0
+    c: 0
+    d: 2305843010430351476
+  Addr: 127.0.0.1:3145
+  PublicKey: 02914bca0806f040dd842207c44474ab41ecd29deee7f2d355789c5c78d448ca16
+  Role: Miner
+- ID: 000003f49592f83d0473bddb70d543f1096b4ffed5e5f942a3117e256b7052b8
+  Nonce:
+    a: 606016
+    b: 0
+    c: 0
+    d: 13835058056920509601
+  Addr: 127.0.0.1:3146
+  PublicKey: 03ae859eac5b72ee428c7a85f10b2ce748d9de5e480aefbb70f6597dfa8b2175e5
+  Role: Miner
diff --git a/test/fuse/node_c/private.key b/test/fuse/node_c/private.key
new file mode 100644
index 000000000..f563980c1
Binary files /dev/null and b/test/fuse/node_c/private.key differ
diff --git a/test/fuse/node_miner_0/config.yaml b/test/fuse/node_miner_0/config.yaml
new file mode 100644
index 000000000..448bb795f
--- /dev/null
+++ b/test/fuse/node_miner_0/config.yaml
@@ -0,0 +1,95 @@
+IsTestMode: true
+WorkingRoot: "./"
+PubKeyStoreFile: "public.keystore"
+PrivateKeyFile: "private.key"
+DHTFileName: "dht.db"
+ListenAddr: "127.0.0.1:3144"
+ThisNodeID: "000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade"
+ValidDNSKeys:
+  koPbw9wmYZ7ggcjnQ6ayHyhHaDNMYELKTqT+qRGrZpWSccr/lBcrm10Z1PuQHB3Azhii+sb0PYFkH1ruxLhe5g==: cloudflare.com
+  mdsswUyr3DPW132mOi8V9xESWE8jTo0dxCjjnopKl+GqJxpVXckHAeF+KkxLbxILfDLUT0rAK9iUzy1L53eKGQ==: cloudflare.com
+BlockProducer:
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  NodeID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  ChainFileName: "chain.db"
+  BPGenesisInfo:
+    Version: 1
+    BlockHash: f745ca6427237aac858dd3c7f2df8e6f3c18d0f1c164e07a1c6b8eebeba6b154
+    Producer: 0000000000000000000000000000000000000000000000000000000000000001
+    MerkleRoot: 0000000000000000000000000000000000000000000000000000000000000001
+    ParentHash: 0000000000000000000000000000000000000000000000000000000000000001
+    Timestamp: 2018-08-13T21:59:59.12Z
+Miner:
+  IsTestMode: true
+  RootDir: "./data"
+  MaxReqTimeGap: "2s"
+  MetricCollectInterval: "1h"
+KnownNodes:
+- ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  Addr: 127.0.0.1:6122
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Leader
+- ID: 00000381d46fd6cf7742d7fb94e2422033af989c0e348b5781b3219599a3af35
+  Nonce:
+    a: 478373
+    b: 0
+    c: 0
+    d: 2305843009893772025
+  Addr: 127.0.0.1:6121
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 000000172580063ded88e010556b0aca2851265be8845b1ef397e8fce6ab5582
+  Nonce:
+    a: 259939
+    b: 0
+    c: 0
+    d: 2305843012544226372
+  Addr: 127.0.0.1:6120
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 00000f3b43288fe99831eb533ab77ec455d13e11fc38ec35a42d4edd17aa320d
+  Nonce:
+    a: 22403
+    b: 0
+    c: 0
+    d: 0
+  Addr: ""
+  PublicKey: 02ec784ca599f21ef93fe7abdc68d78817ab6c9b31f2324d15ea174d9da498b4c4
+  Role: Client
+- ID: 000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade
+  Nonce:
+    a: 567323
+    b: 0
+    c: 0
+    d: 3104982049
+  Addr: 127.0.0.1:3144
+  PublicKey: 0367aa51809a7c1dc0f82c02452fec9557b3e1d10ce7c919d8e73d90048df86d20
+  Role: Miner
+- ID: 000005f4f22c06f76c43c4f48d5a7ec1309cc94030cbf9ebae814172884ac8b5
+  Nonce:
+    a: 240524
+    b: 0
+    c: 0
+    d: 2305843010430351476
+  Addr: 127.0.0.1:3145
+  PublicKey: 02914bca0806f040dd842207c44474ab41ecd29deee7f2d355789c5c78d448ca16
+  Role: Miner
+- ID: 000003f49592f83d0473bddb70d543f1096b4ffed5e5f942a3117e256b7052b8
+  Nonce:
+    a: 606016
+    b: 0
+    c: 0
+    d: 13835058056920509601
+  Addr: 127.0.0.1:3146
+  PublicKey: 03ae859eac5b72ee428c7a85f10b2ce748d9de5e480aefbb70f6597dfa8b2175e5
+  Role: Miner
diff --git a/test/fuse/node_miner_0/private.key b/test/fuse/node_miner_0/private.key
new file mode 100644
index 000000000..12e7d3d80
--- /dev/null
+++ b/test/fuse/node_miner_0/private.key
@@ -0,0 +1 @@
+�8s�_/W�-7Iy�����H_�D����y������T�G����*�M9C#8p%��x�>�S���ߪ�RLmP�B>{�:�̜�����뢷|��|
\ No newline at end of file
diff --git a/test/fuse/node_miner_1/config.yaml b/test/fuse/node_miner_1/config.yaml
new file mode 100644
index 000000000..558ca1cb1
--- /dev/null
+++ b/test/fuse/node_miner_1/config.yaml
@@ -0,0 +1,95 @@
+IsTestMode: true
+WorkingRoot: "./"
+PubKeyStoreFile: "public.keystore"
+PrivateKeyFile: "private.key"
+DHTFileName: "dht.db"
+ListenAddr: "127.0.0.1:3145"
+ThisNodeID: "000005f4f22c06f76c43c4f48d5a7ec1309cc94030cbf9ebae814172884ac8b5"
+ValidDNSKeys:
+  koPbw9wmYZ7ggcjnQ6ayHyhHaDNMYELKTqT+qRGrZpWSccr/lBcrm10Z1PuQHB3Azhii+sb0PYFkH1ruxLhe5g==: cloudflare.com
+  mdsswUyr3DPW132mOi8V9xESWE8jTo0dxCjjnopKl+GqJxpVXckHAeF+KkxLbxILfDLUT0rAK9iUzy1L53eKGQ==: cloudflare.com
+BlockProducer:
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  NodeID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  ChainFileName: "chain.db"
+  BPGenesisInfo:
+    Version: 1
+    BlockHash: f745ca6427237aac858dd3c7f2df8e6f3c18d0f1c164e07a1c6b8eebeba6b154
+    Producer: 0000000000000000000000000000000000000000000000000000000000000001
+    MerkleRoot: 0000000000000000000000000000000000000000000000000000000000000001
+    ParentHash: 0000000000000000000000000000000000000000000000000000000000000001
+    Timestamp: 2018-08-13T21:59:59.12Z
+Miner:
+  IsTestMode: true
+  RootDir: "./data"
+  MaxReqTimeGap: "2s"
+  MetricCollectInterval: "1h"
+KnownNodes:
+- ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  Addr: 127.0.0.1:6122
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Leader
+- ID: 00000381d46fd6cf7742d7fb94e2422033af989c0e348b5781b3219599a3af35
+  Nonce:
+    a: 478373
+    b: 0
+    c: 0
+    d: 2305843009893772025
+  Addr: 127.0.0.1:6121
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 000000172580063ded88e010556b0aca2851265be8845b1ef397e8fce6ab5582
+  Nonce:
+    a: 259939
+    b: 0
+    c: 0
+    d: 2305843012544226372
+  Addr: 127.0.0.1:6120
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 00000f3b43288fe99831eb533ab77ec455d13e11fc38ec35a42d4edd17aa320d
+  Nonce:
+    a: 22403
+    b: 0
+    c: 0
+    d: 0
+  Addr: ""
+  PublicKey: 02ec784ca599f21ef93fe7abdc68d78817ab6c9b31f2324d15ea174d9da498b4c4
+  Role: Client
+- ID: 000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade
+  Nonce:
+    a: 567323
+    b: 0
+    c: 0
+    d: 3104982049
+  Addr: 127.0.0.1:3144
+  PublicKey: 0367aa51809a7c1dc0f82c02452fec9557b3e1d10ce7c919d8e73d90048df86d20
+  Role: Miner
+- ID: 000005f4f22c06f76c43c4f48d5a7ec1309cc94030cbf9ebae814172884ac8b5
+  Nonce:
+    a: 240524
+    b: 0
+    c: 0
+    d: 2305843010430351476
+  Addr: 127.0.0.1:3145
+  PublicKey: 02914bca0806f040dd842207c44474ab41ecd29deee7f2d355789c5c78d448ca16
+  Role: Miner
+- ID: 000003f49592f83d0473bddb70d543f1096b4ffed5e5f942a3117e256b7052b8
+  Nonce:
+    a: 606016
+    b: 0
+    c: 0
+    d: 13835058056920509601
+  Addr: 127.0.0.1:3146
+  PublicKey: 03ae859eac5b72ee428c7a85f10b2ce748d9de5e480aefbb70f6597dfa8b2175e5
+  Role: Miner
diff --git a/test/fuse/node_miner_1/private.key b/test/fuse/node_miner_1/private.key
new file mode 100644
index 000000000..44e8915e6
--- /dev/null
+++ b/test/fuse/node_miner_1/private.key
@@ -0,0 +1,2 @@
+s]�](�o��3R��
+D5�*����9��C
�7�Z�in�ƋSp�*S�S5�^����ޑ��a��x�>�Xо2�#�I�xR�w��+��Ŕ
\ No newline at end of file
diff --git a/test/fuse/node_miner_2/config.yaml b/test/fuse/node_miner_2/config.yaml
new file mode 100644
index 000000000..e6edd4d68
--- /dev/null
+++ b/test/fuse/node_miner_2/config.yaml
@@ -0,0 +1,95 @@
+IsTestMode: true
+WorkingRoot: "./"
+PubKeyStoreFile: "public.keystore"
+PrivateKeyFile: "private.key"
+DHTFileName: "dht.db"
+ListenAddr: "127.0.0.1:3146"
+ThisNodeID: "000003f49592f83d0473bddb70d543f1096b4ffed5e5f942a3117e256b7052b8"
+ValidDNSKeys:
+  koPbw9wmYZ7ggcjnQ6ayHyhHaDNMYELKTqT+qRGrZpWSccr/lBcrm10Z1PuQHB3Azhii+sb0PYFkH1ruxLhe5g==: cloudflare.com
+  mdsswUyr3DPW132mOi8V9xESWE8jTo0dxCjjnopKl+GqJxpVXckHAeF+KkxLbxILfDLUT0rAK9iUzy1L53eKGQ==: cloudflare.com
+BlockProducer:
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  NodeID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  ChainFileName: "chain.db"
+  BPGenesisInfo:
+    Version: 1
+    BlockHash: f745ca6427237aac858dd3c7f2df8e6f3c18d0f1c164e07a1c6b8eebeba6b154
+    Producer: 0000000000000000000000000000000000000000000000000000000000000001
+    MerkleRoot: 0000000000000000000000000000000000000000000000000000000000000001
+    ParentHash: 0000000000000000000000000000000000000000000000000000000000000001
+    Timestamp: 2018-08-13T21:59:59.12Z
+Miner:
+  IsTestMode: true
+  RootDir: "./data"
+  MaxReqTimeGap: "2s"
+  MetricCollectInterval: "1h"
+KnownNodes:
+- ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
+  Nonce:
+    a: 313283
+    b: 0
+    c: 0
+    d: 0
+  Addr: 127.0.0.1:6122
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Leader
+- ID: 00000381d46fd6cf7742d7fb94e2422033af989c0e348b5781b3219599a3af35
+  Nonce:
+    a: 478373
+    b: 0
+    c: 0
+    d: 2305843009893772025
+  Addr: 127.0.0.1:6121
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 000000172580063ded88e010556b0aca2851265be8845b1ef397e8fce6ab5582
+  Nonce:
+    a: 259939
+    b: 0
+    c: 0
+    d: 2305843012544226372
+  Addr: 127.0.0.1:6120
+  PublicKey: "02c76216704d797c64c58bc11519fb68582e8e63de7e5b3b2dbbbe8733efe5fd24"
+  Role: Follower
+- ID: 00000f3b43288fe99831eb533ab77ec455d13e11fc38ec35a42d4edd17aa320d
+  Nonce:
+    a: 22403
+    b: 0
+    c: 0
+    d: 0
+  Addr: ""
+  PublicKey: 02ec784ca599f21ef93fe7abdc68d78817ab6c9b31f2324d15ea174d9da498b4c4
+  Role: Client
+- ID: 000005aa62048f85da4ae9698ed59c14ec0d48a88a07c15a32265634e7e64ade
+  Nonce:
+    a: 567323
+    b: 0
+    c: 0
+    d: 3104982049
+  Addr: 127.0.0.1:3144
+  PublicKey: 0367aa51809a7c1dc0f82c02452fec9557b3e1d10ce7c919d8e73d90048df86d20
+  Role: Miner
+- ID: 000005f4f22c06f76c43c4f48d5a7ec1309cc94030cbf9ebae814172884ac8b5
+  Nonce:
+    a: 240524
+    b: 0
+    c: 0
+    d: 2305843010430351476
+  Addr: 127.0.0.1:3145
+  PublicKey: 02914bca0806f040dd842207c44474ab41ecd29deee7f2d355789c5c78d448ca16
+  Role: Miner
+- ID: 000003f49592f83d0473bddb70d543f1096b4ffed5e5f942a3117e256b7052b8
+  Nonce:
+    a: 606016
+    b: 0
+    c: 0
+    d: 13835058056920509601
+  Addr: 127.0.0.1:3146
+  PublicKey: 03ae859eac5b72ee428c7a85f10b2ce748d9de5e480aefbb70f6597dfa8b2175e5
+  Role: Miner
diff --git a/test/fuse/node_miner_2/private.key b/test/fuse/node_miner_2/private.key
new file mode 100644
index 000000000..adb437e75
--- /dev/null
+++ b/test/fuse/node_miner_2/private.key
@@ -0,0 +1 @@
+�6������i.i%8p�VV���r���L�BK�b: ��1;(���f����F&���y���췥 ��R�W3��?C�A���;e"K2�
\ No newline at end of file
diff --git a/test/integration/node_miner_0/config.yaml b/test/integration/node_miner_0/config.yaml
index 566c0a9b3..8fd498a09 100644
--- a/test/integration/node_miner_0/config.yaml
+++ b/test/integration/node_miner_0/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/integration/node_miner_1/config.yaml b/test/integration/node_miner_1/config.yaml
index a4e87e5ce..a2b44aaf6 100644
--- a/test/integration/node_miner_1/config.yaml
+++ b/test/integration/node_miner_1/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/integration/node_miner_2/config.yaml b/test/integration/node_miner_2/config.yaml
index b63633264..900670988 100644
--- a/test/integration/node_miner_2/config.yaml
+++ b/test/integration/node_miner_2/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/mainchain/node_miner_0/config.yaml b/test/mainchain/node_miner_0/config.yaml
index ffd791a88..b5f65dc73 100644
--- a/test/mainchain/node_miner_0/config.yaml
+++ b/test/mainchain/node_miner_0/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "5s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/mainchain/node_miner_1/config.yaml b/test/mainchain/node_miner_1/config.yaml
index 615d25449..8d88cd5c9 100644
--- a/test/mainchain/node_miner_1/config.yaml
+++ b/test/mainchain/node_miner_1/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "5s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/mainchain/node_miner_2/config.yaml b/test/mainchain/node_miner_2/config.yaml
index 50f67a6b0..3e67adecf 100644
--- a/test/mainchain/node_miner_2/config.yaml
+++ b/test/mainchain/node_miner_2/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "5s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/observation/node_miner_0/config.yaml b/test/observation/node_miner_0/config.yaml
index ff26fc0eb..43934a95e 100644
--- a/test/observation/node_miner_0/config.yaml
+++ b/test/observation/node_miner_0/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/observation/node_miner_1/config.yaml b/test/observation/node_miner_1/config.yaml
index 95bc06940..400a21ad9 100644
--- a/test/observation/node_miner_1/config.yaml
+++ b/test/observation/node_miner_1/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/observation/node_miner_2/config.yaml b/test/observation/node_miner_2/config.yaml
index 0d3303606..edeb37ebc 100644
--- a/test/observation/node_miner_2/config.yaml
+++ b/test/observation/node_miner_2/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/service/node_miner_0/config.yaml b/test/service/node_miner_0/config.yaml
index 415a50fdd..4c981fcb7 100644
--- a/test/service/node_miner_0/config.yaml
+++ b/test/service/node_miner_0/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/service/node_miner_1/config.yaml b/test/service/node_miner_1/config.yaml
index 8e11e22e0..e41bbbb9f 100644
--- a/test/service/node_miner_1/config.yaml
+++ b/test/service/node_miner_1/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/test/service/node_miner_2/config.yaml b/test/service/node_miner_2/config.yaml
index 65d3f034f..00d4caed0 100644
--- a/test/service/node_miner_2/config.yaml
+++ b/test/service/node_miner_2/config.yaml
@@ -28,7 +28,7 @@ Miner:
   IsTestMode: true
   RootDir: "./data"
   MaxReqTimeGap: "2s"
-  MetricCollectInterval: "60s"
+  MetricCollectInterval: "1h"
 KnownNodes:
 - ID: 00000bef611d346c0cbe1beaa76e7f0ed705a194fdf9ac3a248ec70e9c198bf9
   Nonce:
diff --git a/types/ack_type.go b/types/ack_type.go
new file mode 100644
index 000000000..af24a9da9
--- /dev/null
+++ b/types/ack_type.go
@@ -0,0 +1,99 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+)
+
+//go:generate hsp
+
+// AckHeader defines client ack entity.
+type AckHeader struct {
+	Response  SignedResponseHeader `json:"r"`
+	NodeID    proto.NodeID         `json:"i"` // ack node id
+	Timestamp time.Time            `json:"t"` // time in UTC zone
+}
+
+// SignedAckHeader defines client signed ack entity.
+type SignedAckHeader struct {
+	AckHeader
+	verifier.DefaultHashSignVerifierImpl
+}
+
+// Ack defines a whole client ack request entity.
+type Ack struct {
+	proto.Envelope
+	Header SignedAckHeader `json:"h"`
+}
+
+// AckResponse defines client ack response entity.
+type AckResponse struct{}
+
+// Verify checks hash and signature in ack header.
+func (sh *SignedAckHeader) Verify() (err error) {
+	// verify response
+	if err = sh.Response.Verify(); err != nil {
+		return
+	}
+
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.AckHeader)
+}
+
+// Sign the request.
+func (sh *SignedAckHeader) Sign(signer *asymmetric.PrivateKey, verifyReqHeader bool) (err error) {
+	// Only used by ack worker, and ack.Header is verified before build ack
+	if verifyReqHeader {
+		// check original header signature
+		if err = sh.Response.Verify(); err != nil {
+			return
+		}
+	}
+
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.AckHeader, signer)
+}
+
+// Verify checks hash and signature in ack.
+func (a *Ack) Verify() error {
+	return a.Header.Verify()
+}
+
+// Sign the request.
+func (a *Ack) Sign(signer *asymmetric.PrivateKey, verifyReqHeader bool) (err error) {
+	// sign
+	return a.Header.Sign(signer, verifyReqHeader)
+}
+
+// ResponseHash returns the deep shadowed Response Hash field.
+func (sh *SignedAckHeader) ResponseHash() hash.Hash {
+	return sh.AckHeader.Response.Hash()
+}
+
+// SignedRequestHeader returns the deep shadowed Request reference.
+func (sh *SignedAckHeader) SignedRequestHeader() *SignedRequestHeader {
+	return &sh.AckHeader.Response.Request
+}
+
+// SignedResponseHeader returns the Response reference.
+func (sh *SignedAckHeader) SignedResponseHeader() *SignedResponseHeader {
+	return &sh.Response
+}
diff --git a/types/ack_type_gen.go b/types/ack_type_gen.go
new file mode 100644
index 000000000..90fc7a814
--- /dev/null
+++ b/types/ack_type_gen.go
@@ -0,0 +1,111 @@
+package types
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	hsp "github.com/CovenantSQL/HashStablePack/marshalhash"
+)
+
+// MarshalHash marshals for hash
+func (z *Ack) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	if oTemp, err := z.Header.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Envelope.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *Ack) Msgsize() (s int) {
+	s = 1 + 7 + z.Header.Msgsize() + 9 + z.Envelope.Msgsize()
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *AckHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 3
+	o = append(o, 0x83, 0x83)
+	if oTemp, err := z.Response.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x83)
+	if oTemp, err := z.NodeID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x83)
+	o = hsp.AppendTime(o, z.Timestamp)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *AckHeader) Msgsize() (s int) {
+	s = 1 + 9 + z.Response.Msgsize() + 7 + z.NodeID.Msgsize() + 10 + hsp.TimeSize
+	return
+}
+
+// MarshalHash marshals for hash
+func (z AckResponse) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 0
+	o = append(o, 0x80)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z AckResponse) Msgsize() (s int) {
+	s = 1
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *SignedAckHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	// map header, size 3
+	o = append(o, 0x82, 0x82, 0x83, 0x83)
+	if oTemp, err := z.AckHeader.Response.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x83)
+	if oTemp, err := z.AckHeader.NodeID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x83)
+	o = hsp.AppendTime(o, z.AckHeader.Timestamp)
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *SignedAckHeader) Msgsize() (s int) {
+	s = 1 + 10 + 1 + 9 + z.AckHeader.Response.Msgsize() + 7 + z.AckHeader.NodeID.Msgsize() + 10 + hsp.TimeSize + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
+	return
+}
diff --git a/worker/types/ack_type_gen_test.go b/types/ack_type_gen_test.go
similarity index 100%
rename from worker/types/ack_type_gen_test.go
rename to types/ack_type_gen_test.go
diff --git a/sqlchain/types/billing_req.go b/types/billing_req.go
similarity index 100%
rename from sqlchain/types/billing_req.go
rename to types/billing_req.go
diff --git a/types/block.go b/types/block.go
new file mode 100644
index 000000000..e66e688e4
--- /dev/null
+++ b/types/block.go
@@ -0,0 +1,188 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"time"
+
+	ca "github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/CovenantSQL/CovenantSQL/merkle"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
+)
+
+//go:generate hsp
+
+// Header is a block header.
+type Header struct {
+	Version     int32
+	Producer    proto.NodeID
+	GenesisHash hash.Hash
+	ParentHash  hash.Hash
+	MerkleRoot  hash.Hash
+	Timestamp   time.Time
+}
+
+// SignedHeader is block header along with its producer signature.
+type SignedHeader struct {
+	Header
+	HSV verifier.DefaultHashSignVerifierImpl
+}
+
+// Sign calls DefaultHashSignVerifierImpl to calculate header hash and sign it with signer.
+func (s *SignedHeader) Sign(signer *ca.PrivateKey) error {
+	return s.HSV.Sign(&s.Header, signer)
+}
+
+// Verify verifies the signature of the signed header.
+func (s *SignedHeader) Verify() error {
+	return s.HSV.Verify(&s.Header)
+}
+
+// VerifyAsGenesis verifies the signed header as a genesis block header.
+func (s *SignedHeader) VerifyAsGenesis() (err error) {
+	var pk *ca.PublicKey
+	log.WithFields(log.Fields{
+		"producer": s.Producer,
+		"root":     s.GenesisHash.String(),
+		"parent":   s.ParentHash.String(),
+		"merkle":   s.MerkleRoot.String(),
+		"block":    s.HSV.Hash().String(),
+	}).Debug("Verifying genesis block header")
+	if pk, err = kms.GetPublicKey(s.Producer); err != nil {
+		return
+	}
+	if !pk.IsEqual(s.HSV.Signee) {
+		err = ErrNodePublicKeyNotMatch
+		return
+	}
+	return s.Verify()
+}
+
+// QueryAsTx defines a tx struct which is combined with request and signed response header
+// for block.
+type QueryAsTx struct {
+	Request  *Request
+	Response *SignedResponseHeader
+}
+
+// Block is a node of blockchain.
+type Block struct {
+	SignedHeader SignedHeader
+	FailedReqs   []*Request
+	QueryTxs     []*QueryAsTx
+	Acks         []*SignedAckHeader
+}
+
+// CalcNextID calculates the next query id by examinating every query in block, and adds write
+// query number to the last offset.
+//
+// TODO(leventeliu): too tricky. Consider simply adding next id to each block header.
+func (b *Block) CalcNextID() (id uint64, ok bool) {
+	for _, v := range b.QueryTxs {
+		if v.Request.Header.QueryType == WriteQuery {
+			var nid = v.Response.LogOffset + uint64(len(v.Request.Payload.Queries))
+			if nid > id {
+				id = nid
+			}
+			ok = true
+		}
+	}
+	return
+}
+
+// PackAndSignBlock generates the signature for the Block from the given PrivateKey.
+func (b *Block) PackAndSignBlock(signer *ca.PrivateKey) (err error) {
+	// Calculate merkle root
+	b.SignedHeader.MerkleRoot = b.computeMerkleRoot()
+	return b.SignedHeader.Sign(signer)
+}
+
+// Verify verifies the merkle root and header signature of the block.
+func (b *Block) Verify() (err error) {
+	// Verify merkle root
+	if merkleRoot := b.computeMerkleRoot(); !merkleRoot.IsEqual(&b.SignedHeader.MerkleRoot) {
+		return ErrMerkleRootVerification
+	}
+	return b.SignedHeader.Verify()
+}
+
+// VerifyAsGenesis verifies the block as a genesis block.
+func (b *Block) VerifyAsGenesis() (err error) {
+	var pk *ca.PublicKey
+	if pk, err = kms.GetPublicKey(b.SignedHeader.Producer); err != nil {
+		return
+	}
+	if !pk.IsEqual(b.SignedHeader.HSV.Signee) {
+		err = ErrNodePublicKeyNotMatch
+		return
+	}
+	return b.Verify()
+}
+
+// Timestamp returns the timestamp field of the block header.
+func (b *Block) Timestamp() time.Time {
+	return b.SignedHeader.Timestamp
+}
+
+// Producer returns the producer field of the block header.
+func (b *Block) Producer() proto.NodeID {
+	return b.SignedHeader.Producer
+}
+
+// ParentHash returns the parent hash field of the block header.
+func (b *Block) ParentHash() *hash.Hash {
+	return &b.SignedHeader.ParentHash
+}
+
+// BlockHash returns the parent hash field of the block header.
+func (b *Block) BlockHash() *hash.Hash {
+	return &b.SignedHeader.HSV.DataHash
+}
+
+// GenesisHash returns the parent hash field of the block header.
+func (b *Block) GenesisHash() *hash.Hash {
+	return &b.SignedHeader.GenesisHash
+}
+
+// Signee returns the signee field  of the block signed header.
+func (b *Block) Signee() *ca.PublicKey {
+	return b.SignedHeader.HSV.Signee
+}
+
+func (b *Block) computeMerkleRoot() hash.Hash {
+	var hs = make([]*hash.Hash, 0, len(b.FailedReqs)+len(b.QueryTxs)+len(b.Acks))
+	for i := range b.FailedReqs {
+		h := b.FailedReqs[i].Header.Hash()
+		hs = append(hs, &h)
+	}
+	for i := range b.QueryTxs {
+		h := b.QueryTxs[i].Response.Hash()
+		hs = append(hs, &h)
+	}
+	for i := range b.Acks {
+		h := b.Acks[i].Hash()
+		hs = append(hs, &h)
+	}
+	return *merkle.NewMerkle(hs).GetRoot()
+}
+
+// Blocks is Block (reference) array.
+type Blocks []*Block
diff --git a/types/block_gen.go b/types/block_gen.go
new file mode 100644
index 000000000..bf8ef8bd6
--- /dev/null
+++ b/types/block_gen.go
@@ -0,0 +1,241 @@
+package types
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	hsp "github.com/CovenantSQL/HashStablePack/marshalhash"
+)
+
+// MarshalHash marshals for hash
+func (z *Block) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 4
+	// map header, size 2
+	o = append(o, 0x84, 0x84, 0x82, 0x82)
+	if oTemp, err := z.SignedHeader.Header.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.SignedHeader.HSV.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x84)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.QueryTxs)))
+	for za0002 := range z.QueryTxs {
+		if z.QueryTxs[za0002] == nil {
+			o = hsp.AppendNil(o)
+		} else {
+			if oTemp, err := z.QueryTxs[za0002].MarshalHash(); err != nil {
+				return nil, err
+			} else {
+				o = hsp.AppendBytes(o, oTemp)
+			}
+		}
+	}
+	o = append(o, 0x84)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.FailedReqs)))
+	for za0001 := range z.FailedReqs {
+		if z.FailedReqs[za0001] == nil {
+			o = hsp.AppendNil(o)
+		} else {
+			if oTemp, err := z.FailedReqs[za0001].MarshalHash(); err != nil {
+				return nil, err
+			} else {
+				o = hsp.AppendBytes(o, oTemp)
+			}
+		}
+	}
+	o = append(o, 0x84)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.Acks)))
+	for za0003 := range z.Acks {
+		if z.Acks[za0003] == nil {
+			o = hsp.AppendNil(o)
+		} else {
+			if oTemp, err := z.Acks[za0003].MarshalHash(); err != nil {
+				return nil, err
+			} else {
+				o = hsp.AppendBytes(o, oTemp)
+			}
+		}
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *Block) Msgsize() (s int) {
+	s = 1 + 13 + 1 + 7 + z.SignedHeader.Header.Msgsize() + 4 + z.SignedHeader.HSV.Msgsize() + 9 + hsp.ArrayHeaderSize
+	for za0002 := range z.QueryTxs {
+		if z.QueryTxs[za0002] == nil {
+			s += hsp.NilSize
+		} else {
+			s += z.QueryTxs[za0002].Msgsize()
+		}
+	}
+	s += 11 + hsp.ArrayHeaderSize
+	for za0001 := range z.FailedReqs {
+		if z.FailedReqs[za0001] == nil {
+			s += hsp.NilSize
+		} else {
+			s += z.FailedReqs[za0001].Msgsize()
+		}
+	}
+	s += 5 + hsp.ArrayHeaderSize
+	for za0003 := range z.Acks {
+		if z.Acks[za0003] == nil {
+			s += hsp.NilSize
+		} else {
+			s += z.Acks[za0003].Msgsize()
+		}
+	}
+	return
+}
+
+// MarshalHash marshals for hash
+func (z Blocks) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	o = hsp.AppendArrayHeader(o, uint32(len(z)))
+	for za0001 := range z {
+		if z[za0001] == nil {
+			o = hsp.AppendNil(o)
+		} else {
+			if oTemp, err := z[za0001].MarshalHash(); err != nil {
+				return nil, err
+			} else {
+				o = hsp.AppendBytes(o, oTemp)
+			}
+		}
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z Blocks) Msgsize() (s int) {
+	s = hsp.ArrayHeaderSize
+	for za0001 := range z {
+		if z[za0001] == nil {
+			s += hsp.NilSize
+		} else {
+			s += z[za0001].Msgsize()
+		}
+	}
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *Header) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 6
+	o = append(o, 0x86, 0x86)
+	if oTemp, err := z.GenesisHash.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x86)
+	if oTemp, err := z.ParentHash.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x86)
+	if oTemp, err := z.MerkleRoot.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x86)
+	o = hsp.AppendInt32(o, z.Version)
+	o = append(o, 0x86)
+	if oTemp, err := z.Producer.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x86)
+	o = hsp.AppendTime(o, z.Timestamp)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *Header) Msgsize() (s int) {
+	s = 1 + 12 + z.GenesisHash.Msgsize() + 11 + z.ParentHash.Msgsize() + 11 + z.MerkleRoot.Msgsize() + 8 + hsp.Int32Size + 9 + z.Producer.Msgsize() + 10 + hsp.TimeSize
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *QueryAsTx) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	if z.Request == nil {
+		o = hsp.AppendNil(o)
+	} else {
+		if oTemp, err := z.Request.MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	o = append(o, 0x82)
+	if z.Response == nil {
+		o = hsp.AppendNil(o)
+	} else {
+		if oTemp, err := z.Response.MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *QueryAsTx) Msgsize() (s int) {
+	s = 1 + 8
+	if z.Request == nil {
+		s += hsp.NilSize
+	} else {
+		s += z.Request.Msgsize()
+	}
+	s += 9
+	if z.Response == nil {
+		s += hsp.NilSize
+	} else {
+		s += z.Response.Msgsize()
+	}
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *SignedHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	if oTemp, err := z.Header.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.HSV.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *SignedHeader) Msgsize() (s int) {
+	s = 1 + 7 + z.Header.Msgsize() + 4 + z.HSV.Msgsize()
+	return
+}
diff --git a/types/block_gen_test.go b/types/block_gen_test.go
new file mode 100644
index 000000000..ff2b94d1d
--- /dev/null
+++ b/types/block_gen_test.go
@@ -0,0 +1,195 @@
+package types
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/binary"
+	"testing"
+)
+
+func TestMarshalHashBlock(t *testing.T) {
+	v := Block{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashBlock(b *testing.B) {
+	v := Block{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgBlock(b *testing.B) {
+	v := Block{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashBlocks(t *testing.T) {
+	v := Blocks{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashBlocks(b *testing.B) {
+	v := Blocks{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgBlocks(b *testing.B) {
+	v := Blocks{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashHeader(t *testing.T) {
+	v := Header{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashHeader(b *testing.B) {
+	v := Header{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgHeader(b *testing.B) {
+	v := Header{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashQueryAsTx(t *testing.T) {
+	v := QueryAsTx{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashQueryAsTx(b *testing.B) {
+	v := QueryAsTx{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgQueryAsTx(b *testing.B) {
+	v := QueryAsTx{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashSignedHeader(t *testing.T) {
+	v := SignedHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashSignedHeader(b *testing.B) {
+	v := SignedHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgSignedHeader(b *testing.B) {
+	v := SignedHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
diff --git a/types/block_test.go b/types/block_test.go
new file mode 100644
index 000000000..e028babde
--- /dev/null
+++ b/types/block_test.go
@@ -0,0 +1,450 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"bytes"
+	"math/big"
+	"reflect"
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/CovenantSQL/CovenantSQL/utils"
+	"github.com/pkg/errors"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestSignAndVerify(t *testing.T) {
+	block, err := createRandomBlock(genesisHash, true)
+
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	if err = block.Verify(); err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	block.SignedHeader.HSV.DataHash[0]++
+
+	if err = errors.Cause(block.Verify()); err != verifier.ErrHashValueNotMatch {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+
+	block.Acks = append(block.Acks, &SignedAckHeader{
+		DefaultHashSignVerifierImpl: verifier.DefaultHashSignVerifierImpl{
+			DataHash: hash.Hash{0x01},
+		},
+	})
+
+	if err = block.Verify(); err != ErrMerkleRootVerification {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+}
+
+func TestHeaderMarshalUnmarshaler(t *testing.T) {
+	block, err := createRandomBlock(genesisHash, false)
+
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	origin := &block.SignedHeader.Header
+	enc, err := utils.EncodeMsgPack(origin)
+
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	dec := &Header{}
+	if err = utils.DecodeMsgPack(enc.Bytes(), dec); err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	bts1, err := origin.MarshalHash()
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	bts2, err := dec.MarshalHash()
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+
+	if !reflect.DeepEqual(origin, dec) {
+		t.Fatalf("Values don't match:\n\tv1 = %+v\n\tv2 = %+v", origin, dec)
+	}
+}
+
+func TestSignedHeaderMarshaleUnmarshaler(t *testing.T) {
+	block, err := createRandomBlock(genesisHash, true)
+
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	origin := &block.SignedHeader
+	enc, err := utils.EncodeMsgPack(origin)
+
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	dec := &SignedHeader{}
+
+	if err = utils.DecodeMsgPack(enc.Bytes(), dec); err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	bts1, err := origin.MarshalHash()
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	bts2, err := dec.MarshalHash()
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+
+	if !reflect.DeepEqual(origin.Header, dec.Header) {
+		t.Fatalf("Values don't match:\n\tv1 = %+v\n\tv2 = %+v", origin.Header, dec.Header)
+	}
+
+	if err = origin.Verify(); err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	if err = dec.Verify(); err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+}
+
+func TestBlockMarshalUnmarshaler(t *testing.T) {
+	origin, err := createRandomBlock(genesisHash, false)
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+	origin2, err := createRandomBlock(genesisHash, false)
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	blocks := make(Blocks, 0, 2)
+	blocks = append(blocks, origin)
+	blocks = append(blocks, origin2)
+	blocks = append(blocks, nil)
+
+	blocks2 := make(Blocks, 0, 2)
+	blocks2 = append(blocks2, origin)
+	blocks2 = append(blocks2, origin2)
+	blocks2 = append(blocks2, nil)
+
+	bts1, err := blocks.MarshalHash()
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	bts2, err := blocks2.MarshalHash()
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+
+	enc, err := utils.EncodeMsgPack(origin)
+
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	dec := &Block{}
+
+	if err = utils.DecodeMsgPack(enc.Bytes(), dec); err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	bts1, err = origin.MarshalHash()
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	bts2, err = dec.MarshalHash()
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+
+	if !reflect.DeepEqual(origin, dec) {
+		t.Fatalf("Values don't match:\n\tv1 = %+v\n\tv2 = %+v", origin, dec)
+	}
+}
+
+func TestGenesis(t *testing.T) {
+	genesis, err := createRandomBlock(genesisHash, true)
+
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	if err = genesis.VerifyAsGenesis(); err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	if err = genesis.SignedHeader.VerifyAsGenesis(); err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	// Test non-genesis block
+	genesis, err = createRandomBlock(genesisHash, false)
+
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	if err = genesis.VerifyAsGenesis(); err != nil {
+		t.Logf("Error occurred as expected: %v", err)
+	} else {
+		t.Fatal("Unexpected result: returned nil while expecting an error")
+	}
+
+	if err = genesis.SignedHeader.VerifyAsGenesis(); err != nil {
+		t.Logf("Error occurred as expected: %v", err)
+	} else {
+		t.Fatal("Unexpected result: returned nil while expecting an error")
+	}
+
+	// Test altered public key block
+	genesis, err = createRandomBlock(genesisHash, true)
+
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	_, pub, err := asymmetric.GenSecp256k1KeyPair()
+
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	genesis.SignedHeader.HSV.Signee = pub
+
+	if err = genesis.VerifyAsGenesis(); err != nil {
+		t.Logf("Error occurred as expected: %v", err)
+	} else {
+		t.Fatal("Unexpected result: returned nil while expecting an error")
+	}
+
+	if err = genesis.SignedHeader.VerifyAsGenesis(); err != nil {
+		t.Logf("Error occurred as expected: %v", err)
+	} else {
+		t.Fatal("Unexpected result: returned nil while expecting an error")
+	}
+
+	// Test altered signature
+	genesis, err = createRandomBlock(genesisHash, true)
+
+	if err != nil {
+		t.Fatalf("Error occurred: %v", err)
+	}
+
+	genesis.SignedHeader.HSV.Signature.R.Add(genesis.SignedHeader.HSV.Signature.R, big.NewInt(int64(1)))
+	genesis.SignedHeader.HSV.Signature.S.Add(genesis.SignedHeader.HSV.Signature.S, big.NewInt(int64(1)))
+
+	if err = genesis.VerifyAsGenesis(); err != nil {
+		t.Logf("Error occurred as expected: %v", err)
+	} else {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+
+	if err = genesis.SignedHeader.VerifyAsGenesis(); err != nil {
+		t.Logf("Error occurred as expected: %v", err)
+	} else {
+		t.Fatal("Unexpected result: returned nil while expecting an error")
+	}
+}
+
+func Test(t *testing.T) {
+	Convey("CalcNextID should return correct id of each testing block", t, func() {
+		var (
+			nextid uint64
+			ok     bool
+
+			cases = [...]struct {
+				block  *Block
+				nextid uint64
+				ok     bool
+			}{
+				{
+					block: &Block{
+						QueryTxs: []*QueryAsTx{},
+					},
+					nextid: 0,
+					ok:     false,
+				}, {
+					block: &Block{
+						QueryTxs: nil,
+					},
+					nextid: 0,
+					ok:     false,
+				}, {
+					block: &Block{
+						QueryTxs: []*QueryAsTx{
+							&QueryAsTx{
+								Request: &Request{
+									Header: SignedRequestHeader{
+										RequestHeader: RequestHeader{
+											QueryType: ReadQuery,
+										},
+									},
+									Payload: RequestPayload{
+										Queries: make([]Query, 10),
+									},
+								},
+								Response: &SignedResponseHeader{
+									ResponseHeader: ResponseHeader{
+										LogOffset: 0,
+									},
+								},
+							},
+						},
+					},
+					nextid: 0,
+					ok:     false,
+				}, {
+					block: &Block{
+						QueryTxs: []*QueryAsTx{
+							&QueryAsTx{
+								Request: &Request{
+									Header: SignedRequestHeader{
+										RequestHeader: RequestHeader{
+											QueryType: WriteQuery,
+										},
+									},
+									Payload: RequestPayload{
+										Queries: make([]Query, 10),
+									},
+								},
+								Response: &SignedResponseHeader{
+									ResponseHeader: ResponseHeader{
+										LogOffset: 0,
+									},
+								},
+							},
+						},
+					},
+					nextid: 10,
+					ok:     true,
+				}, {
+					block: &Block{
+						QueryTxs: []*QueryAsTx{
+							&QueryAsTx{
+								Request: &Request{
+									Header: SignedRequestHeader{
+										RequestHeader: RequestHeader{
+											QueryType: ReadQuery,
+										},
+									},
+									Payload: RequestPayload{
+										Queries: make([]Query, 10),
+									},
+								},
+								Response: &SignedResponseHeader{
+									ResponseHeader: ResponseHeader{
+										LogOffset: 0,
+									},
+								},
+							}, &QueryAsTx{
+								Request: &Request{
+									Header: SignedRequestHeader{
+										RequestHeader: RequestHeader{
+											QueryType: WriteQuery,
+										},
+									},
+									Payload: RequestPayload{
+										Queries: make([]Query, 10),
+									},
+								},
+								Response: &SignedResponseHeader{
+									ResponseHeader: ResponseHeader{
+										LogOffset: 0,
+									},
+								},
+							}, &QueryAsTx{
+								Request: &Request{
+									Header: SignedRequestHeader{
+										RequestHeader: RequestHeader{
+											QueryType: ReadQuery,
+										},
+									},
+									Payload: RequestPayload{
+										Queries: make([]Query, 10),
+									},
+								},
+								Response: &SignedResponseHeader{
+									ResponseHeader: ResponseHeader{
+										LogOffset: 10,
+									},
+								},
+							}, &QueryAsTx{
+								Request: &Request{
+									Header: SignedRequestHeader{
+										RequestHeader: RequestHeader{
+											QueryType: WriteQuery,
+										},
+									},
+									Payload: RequestPayload{
+										Queries: make([]Query, 20),
+									},
+								},
+								Response: &SignedResponseHeader{
+									ResponseHeader: ResponseHeader{
+										LogOffset: 10,
+									},
+								},
+							},
+						},
+					},
+					nextid: 30,
+					ok:     true,
+				},
+			}
+		)
+
+		for _, v := range cases {
+			nextid, ok = v.block.CalcNextID()
+			So(ok, ShouldEqual, v.ok)
+			if ok {
+				So(nextid, ShouldEqual, v.nextid)
+			}
+		}
+	})
+}
diff --git a/types/build.sh b/types/build.sh
deleted file mode 100755
index 2b9fd9b67..000000000
--- a/types/build.sh
+++ /dev/null
@@ -1,4 +0,0 @@
-#! /usr/bin/env bash
-
-declare -r PB_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-protoc -I="$PB_DIR" --go_out="$PB_DIR" "$PB_DIR"/*.proto
diff --git a/blockproducer/db_service_types.go b/types/db_service_types.go
similarity index 62%
rename from blockproducer/db_service_types.go
rename to types/db_service_types.go
index 3f94c991f..89c69bafa 100644
--- a/blockproducer/db_service_types.go
+++ b/types/db_service_types.go
@@ -14,55 +14,35 @@
  * limitations under the License.
  */
 
-package blockproducer
+package types
 
 import (
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
-	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
 	"github.com/CovenantSQL/CovenantSQL/proto"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 )
 
 //go:generate hsp
 
 // CreateDatabaseRequestHeader defines client create database rpc header.
 type CreateDatabaseRequestHeader struct {
-	ResourceMeta wt.ResourceMeta
+	ResourceMeta ResourceMeta
 }
 
 // SignedCreateDatabaseRequestHeader defines signed client create database request header.
 type SignedCreateDatabaseRequestHeader struct {
 	CreateDatabaseRequestHeader
-	Hash      hash.Hash
-	Signee    *asymmetric.PublicKey
-	Signature *asymmetric.Signature
+	verifier.DefaultHashSignVerifierImpl
 }
 
 // Verify checks hash and signature in create database request header.
 func (sh *SignedCreateDatabaseRequestHeader) Verify() (err error) {
-	// verify hash
-	if err = verifyHash(&sh.CreateDatabaseRequestHeader, &sh.Hash); err != nil {
-		return
-	}
-	// verify sign
-	if sh.Signee == nil || sh.Signature == nil || !sh.Signature.Verify(sh.Hash[:], sh.Signee) {
-		return wt.ErrSignVerification
-	}
-	return
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.CreateDatabaseRequestHeader)
 }
 
 // Sign the request.
 func (sh *SignedCreateDatabaseRequestHeader) Sign(signer *asymmetric.PrivateKey) (err error) {
-	// build hash
-	if err = buildHash(&sh.CreateDatabaseRequestHeader, &sh.Hash); err != nil {
-		return
-	}
-
-	// sign
-	sh.Signature, err = signer.Sign(sh.Hash[:])
-	sh.Signee = signer.PubKey()
-
-	return
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.CreateDatabaseRequestHeader, signer)
 }
 
 // CreateDatabaseRequest defines client create database rpc request entity.
@@ -84,42 +64,23 @@ func (r *CreateDatabaseRequest) Sign(signer *asymmetric.PrivateKey) (err error)
 
 // CreateDatabaseResponseHeader defines client create database rpc response header.
 type CreateDatabaseResponseHeader struct {
-	InstanceMeta wt.ServiceInstance
+	InstanceMeta ServiceInstance
 }
 
 // SignedCreateDatabaseResponseHeader defines signed client create database response header.
 type SignedCreateDatabaseResponseHeader struct {
 	CreateDatabaseResponseHeader
-	Hash      hash.Hash
-	Signee    *asymmetric.PublicKey
-	Signature *asymmetric.Signature
+	verifier.DefaultHashSignVerifierImpl
 }
 
 // Verify checks hash and signature in create database response header.
 func (sh *SignedCreateDatabaseResponseHeader) Verify() (err error) {
-	// verify hash
-	if err = verifyHash(&sh.CreateDatabaseResponseHeader, &sh.Hash); err != nil {
-		return
-	}
-	// verify sign
-	if sh.Signee == nil || sh.Signature == nil || !sh.Signature.Verify(sh.Hash[:], sh.Signee) {
-		return wt.ErrSignVerification
-	}
-	return
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.CreateDatabaseResponseHeader)
 }
 
 // Sign the response.
 func (sh *SignedCreateDatabaseResponseHeader) Sign(signer *asymmetric.PrivateKey) (err error) {
-	// build hash
-	if err = buildHash(&sh.CreateDatabaseResponseHeader, &sh.Hash); err != nil {
-		return
-	}
-
-	// sign
-	sh.Signature, err = signer.Sign(sh.Hash[:])
-	sh.Signee = signer.PubKey()
-
-	return
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.CreateDatabaseResponseHeader, signer)
 }
 
 // CreateDatabaseResponse defines client create database rpc response entity.
@@ -147,36 +108,17 @@ type DropDatabaseRequestHeader struct {
 // SignedDropDatabaseRequestHeader defines signed client drop database rpc request header.
 type SignedDropDatabaseRequestHeader struct {
 	DropDatabaseRequestHeader
-	Hash      hash.Hash
-	Signee    *asymmetric.PublicKey
-	Signature *asymmetric.Signature
+	verifier.DefaultHashSignVerifierImpl
 }
 
 // Verify checks hash and signature in request header.
 func (sh *SignedDropDatabaseRequestHeader) Verify() (err error) {
-	// verify hash
-	if err = verifyHash(&sh.DropDatabaseRequestHeader, &sh.Hash); err != nil {
-		return
-	}
-	// verify sign
-	if sh.Signee == nil || sh.Signature == nil || !sh.Signature.Verify(sh.Hash[:], sh.Signee) {
-		return wt.ErrSignVerification
-	}
-	return
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.DropDatabaseRequestHeader)
 }
 
 // Sign the request.
 func (sh *SignedDropDatabaseRequestHeader) Sign(signer *asymmetric.PrivateKey) (err error) {
-	// build hash
-	if err = buildHash(&sh.DropDatabaseRequestHeader, &sh.Hash); err != nil {
-		return
-	}
-
-	// sign
-	sh.Signature, err = signer.Sign(sh.Hash[:])
-	sh.Signee = signer.PubKey()
-
-	return
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.DropDatabaseRequestHeader, signer)
 }
 
 // DropDatabaseRequest defines client drop database rpc request entity.
@@ -206,36 +148,17 @@ type GetDatabaseRequestHeader struct {
 // SignedGetDatabaseRequestHeader defines signed client get database rpc request header entity.
 type SignedGetDatabaseRequestHeader struct {
 	GetDatabaseRequestHeader
-	Hash      hash.Hash
-	Signee    *asymmetric.PublicKey
-	Signature *asymmetric.Signature
+	verifier.DefaultHashSignVerifierImpl
 }
 
 // Verify checks hash and signature in request header.
 func (sh *SignedGetDatabaseRequestHeader) Verify() (err error) {
-	// verify hash
-	if err = verifyHash(&sh.GetDatabaseRequestHeader, &sh.Hash); err != nil {
-		return
-	}
-	// verify sign
-	if sh.Signee == nil || sh.Signature == nil || !sh.Signature.Verify(sh.Hash[:], sh.Signee) {
-		return wt.ErrSignVerification
-	}
-	return
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.GetDatabaseRequestHeader)
 }
 
 // Sign the request.
 func (sh *SignedGetDatabaseRequestHeader) Sign(signer *asymmetric.PrivateKey) (err error) {
-	// build hash
-	if err = buildHash(&sh.GetDatabaseRequestHeader, &sh.Hash); err != nil {
-		return
-	}
-
-	// sign
-	sh.Signature, err = signer.Sign(sh.Hash[:])
-	sh.Signee = signer.PubKey()
-
-	return
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.GetDatabaseRequestHeader, signer)
 }
 
 // GetDatabaseRequest defines client get database rpc request entity.
@@ -256,42 +179,23 @@ func (r *GetDatabaseRequest) Sign(signer *asymmetric.PrivateKey) error {
 
 // GetDatabaseResponseHeader defines client get database rpc response header entity.
 type GetDatabaseResponseHeader struct {
-	InstanceMeta wt.ServiceInstance
+	InstanceMeta ServiceInstance
 }
 
 // SignedGetDatabaseResponseHeader defines client get database rpc response header entity.
 type SignedGetDatabaseResponseHeader struct {
 	GetDatabaseResponseHeader
-	Hash      hash.Hash
-	Signee    *asymmetric.PublicKey
-	Signature *asymmetric.Signature
+	verifier.DefaultHashSignVerifierImpl
 }
 
 // Verify checks hash and signature in response header.
 func (sh *SignedGetDatabaseResponseHeader) Verify() (err error) {
-	// verify hash
-	if err = verifyHash(&sh.GetDatabaseResponseHeader, &sh.Hash); err != nil {
-		return
-	}
-	// verify sign
-	if sh.Signee == nil || sh.Signature == nil || !sh.Signature.Verify(sh.Hash[:], sh.Signee) {
-		return wt.ErrSignVerification
-	}
-	return
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.GetDatabaseResponseHeader)
 }
 
 // Sign the request.
 func (sh *SignedGetDatabaseResponseHeader) Sign(signer *asymmetric.PrivateKey) (err error) {
-	// build hash
-	if err = buildHash(&sh.GetDatabaseResponseHeader, &sh.Hash); err != nil {
-		return
-	}
-
-	// sign
-	sh.Signature, err = signer.Sign(sh.Hash[:])
-	sh.Signee = signer.PubKey()
-
-	return
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.GetDatabaseResponseHeader, signer)
 }
 
 // GetDatabaseResponse defines client get database rpc response entity.
@@ -309,29 +213,3 @@ func (r *GetDatabaseResponse) Verify() (err error) {
 func (r *GetDatabaseResponse) Sign(signer *asymmetric.PrivateKey) (err error) {
 	return r.Header.Sign(signer)
 }
-
-// FIXME(xq262144) remove duplicated interface in utils package.
-type canMarshalHash interface {
-	MarshalHash() ([]byte, error)
-}
-
-func verifyHash(data canMarshalHash, h *hash.Hash) (err error) {
-	var newHash hash.Hash
-	if err = buildHash(data, &newHash); err != nil {
-		return
-	}
-	if !newHash.IsEqual(h) {
-		return ErrSignVerification
-	}
-	return
-}
-
-func buildHash(data canMarshalHash, h *hash.Hash) (err error) {
-	var hashBytes []byte
-	if hashBytes, err = data.MarshalHash(); err != nil {
-		return
-	}
-	newHash := hash.THashH(hashBytes)
-	copy(h[:], newHash[:])
-	return
-}
diff --git a/blockproducer/db_service_types_gen.go b/types/db_service_types_gen.go
similarity index 65%
rename from blockproducer/db_service_types_gen.go
rename to types/db_service_types_gen.go
index 4ab068cbb..188fcada8 100644
--- a/blockproducer/db_service_types_gen.go
+++ b/types/db_service_types_gen.go
@@ -1,4 +1,4 @@
-package blockproducer
+package types
 
 // Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
 
@@ -11,8 +11,16 @@ func (z *CreateDatabaseRequest) MarshalHash() (o []byte, err error) {
 	var b []byte
 	o = hsp.Require(b, z.Msgsize())
 	// map header, size 2
-	o = append(o, 0x82, 0x82)
-	if oTemp, err := z.Header.MarshalHash(); err != nil {
+	// map header, size 2
+	// map header, size 1
+	o = append(o, 0x82, 0x82, 0x82, 0x82, 0x81, 0x81)
+	if oTemp, err := z.Header.CreateDatabaseRequestHeader.ResourceMeta.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Header.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -28,7 +36,7 @@ func (z *CreateDatabaseRequest) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *CreateDatabaseRequest) Msgsize() (s int) {
-	s = 1 + 7 + z.Header.Msgsize() + 9 + z.Envelope.Msgsize()
+	s = 1 + 7 + 1 + 28 + 1 + 13 + z.Header.CreateDatabaseRequestHeader.ResourceMeta.Msgsize() + 28 + z.Header.DefaultHashSignVerifierImpl.Msgsize() + 9 + z.Envelope.Msgsize()
 	return
 }
 
@@ -57,8 +65,16 @@ func (z *CreateDatabaseResponse) MarshalHash() (o []byte, err error) {
 	var b []byte
 	o = hsp.Require(b, z.Msgsize())
 	// map header, size 2
-	o = append(o, 0x82, 0x82)
-	if oTemp, err := z.Header.MarshalHash(); err != nil {
+	// map header, size 2
+	// map header, size 1
+	o = append(o, 0x82, 0x82, 0x82, 0x82, 0x81, 0x81)
+	if oTemp, err := z.Header.CreateDatabaseResponseHeader.InstanceMeta.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Header.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -74,7 +90,7 @@ func (z *CreateDatabaseResponse) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *CreateDatabaseResponse) Msgsize() (s int) {
-	s = 1 + 7 + z.Header.Msgsize() + 9 + z.Envelope.Msgsize()
+	s = 1 + 7 + 1 + 29 + 1 + 13 + z.Header.CreateDatabaseResponseHeader.InstanceMeta.Msgsize() + 28 + z.Header.DefaultHashSignVerifierImpl.Msgsize() + 9 + z.Envelope.Msgsize()
 	return
 }
 
@@ -103,8 +119,16 @@ func (z *DropDatabaseRequest) MarshalHash() (o []byte, err error) {
 	var b []byte
 	o = hsp.Require(b, z.Msgsize())
 	// map header, size 2
-	o = append(o, 0x82, 0x82)
-	if oTemp, err := z.Header.MarshalHash(); err != nil {
+	// map header, size 2
+	// map header, size 1
+	o = append(o, 0x82, 0x82, 0x82, 0x82, 0x81, 0x81)
+	if oTemp, err := z.Header.DropDatabaseRequestHeader.DatabaseID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Header.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -120,7 +144,7 @@ func (z *DropDatabaseRequest) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *DropDatabaseRequest) Msgsize() (s int) {
-	s = 1 + 7 + z.Header.Msgsize() + 9 + z.Envelope.Msgsize()
+	s = 1 + 7 + 1 + 26 + 1 + 11 + z.Header.DropDatabaseRequestHeader.DatabaseID.Msgsize() + 28 + z.Header.DefaultHashSignVerifierImpl.Msgsize() + 9 + z.Envelope.Msgsize()
 	return
 }
 
@@ -164,8 +188,16 @@ func (z *GetDatabaseRequest) MarshalHash() (o []byte, err error) {
 	var b []byte
 	o = hsp.Require(b, z.Msgsize())
 	// map header, size 2
-	o = append(o, 0x82, 0x82)
-	if oTemp, err := z.Header.MarshalHash(); err != nil {
+	// map header, size 2
+	// map header, size 1
+	o = append(o, 0x82, 0x82, 0x82, 0x82, 0x81, 0x81)
+	if oTemp, err := z.Header.GetDatabaseRequestHeader.DatabaseID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Header.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -181,7 +213,7 @@ func (z *GetDatabaseRequest) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *GetDatabaseRequest) Msgsize() (s int) {
-	s = 1 + 7 + z.Header.Msgsize() + 9 + z.Envelope.Msgsize()
+	s = 1 + 7 + 1 + 25 + 1 + 11 + z.Header.GetDatabaseRequestHeader.DatabaseID.Msgsize() + 28 + z.Header.DefaultHashSignVerifierImpl.Msgsize() + 9 + z.Envelope.Msgsize()
 	return
 }
 
@@ -210,8 +242,16 @@ func (z *GetDatabaseResponse) MarshalHash() (o []byte, err error) {
 	var b []byte
 	o = hsp.Require(b, z.Msgsize())
 	// map header, size 2
-	o = append(o, 0x82, 0x82)
-	if oTemp, err := z.Header.MarshalHash(); err != nil {
+	// map header, size 2
+	// map header, size 1
+	o = append(o, 0x82, 0x82, 0x82, 0x82, 0x81, 0x81)
+	if oTemp, err := z.Header.GetDatabaseResponseHeader.InstanceMeta.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Header.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -227,7 +267,7 @@ func (z *GetDatabaseResponse) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *GetDatabaseResponse) Msgsize() (s int) {
-	s = 1 + 7 + z.Header.Msgsize() + 9 + z.Envelope.Msgsize()
+	s = 1 + 7 + 1 + 26 + 1 + 13 + z.Header.GetDatabaseResponseHeader.InstanceMeta.Msgsize() + 28 + z.Header.DefaultHashSignVerifierImpl.Msgsize() + 9 + z.Envelope.Msgsize()
 	return
 }
 
@@ -255,36 +295,16 @@ func (z *GetDatabaseResponseHeader) Msgsize() (s int) {
 func (z *SignedCreateDatabaseRequestHeader) MarshalHash() (o []byte, err error) {
 	var b []byte
 	o = hsp.Require(b, z.Msgsize())
-	// map header, size 4
-	o = append(o, 0x84, 0x84)
-	if z.Signee == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signee.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
-	o = append(o, 0x84)
-	if z.Signature == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signature.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
+	// map header, size 2
 	// map header, size 1
-	o = append(o, 0x84, 0x81, 0x81)
+	o = append(o, 0x82, 0x82, 0x81, 0x81)
 	if oTemp, err := z.CreateDatabaseRequestHeader.ResourceMeta.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
 	}
-	o = append(o, 0x84)
-	if oTemp, err := z.Hash.MarshalHash(); err != nil {
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -294,19 +314,7 @@ func (z *SignedCreateDatabaseRequestHeader) MarshalHash() (o []byte, err error)
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *SignedCreateDatabaseRequestHeader) Msgsize() (s int) {
-	s = 1 + 7
-	if z.Signee == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signee.Msgsize()
-	}
-	s += 10
-	if z.Signature == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signature.Msgsize()
-	}
-	s += 28 + 1 + 13 + z.CreateDatabaseRequestHeader.ResourceMeta.Msgsize() + 5 + z.Hash.Msgsize()
+	s = 1 + 28 + 1 + 13 + z.CreateDatabaseRequestHeader.ResourceMeta.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
 	return
 }
 
@@ -314,36 +322,16 @@ func (z *SignedCreateDatabaseRequestHeader) Msgsize() (s int) {
 func (z *SignedCreateDatabaseResponseHeader) MarshalHash() (o []byte, err error) {
 	var b []byte
 	o = hsp.Require(b, z.Msgsize())
-	// map header, size 4
-	o = append(o, 0x84, 0x84)
-	if z.Signee == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signee.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
-	o = append(o, 0x84)
-	if z.Signature == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signature.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
+	// map header, size 2
 	// map header, size 1
-	o = append(o, 0x84, 0x81, 0x81)
+	o = append(o, 0x82, 0x82, 0x81, 0x81)
 	if oTemp, err := z.CreateDatabaseResponseHeader.InstanceMeta.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
 	}
-	o = append(o, 0x84)
-	if oTemp, err := z.Hash.MarshalHash(); err != nil {
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -353,19 +341,7 @@ func (z *SignedCreateDatabaseResponseHeader) MarshalHash() (o []byte, err error)
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *SignedCreateDatabaseResponseHeader) Msgsize() (s int) {
-	s = 1 + 7
-	if z.Signee == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signee.Msgsize()
-	}
-	s += 10
-	if z.Signature == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signature.Msgsize()
-	}
-	s += 29 + 1 + 13 + z.CreateDatabaseResponseHeader.InstanceMeta.Msgsize() + 5 + z.Hash.Msgsize()
+	s = 1 + 29 + 1 + 13 + z.CreateDatabaseResponseHeader.InstanceMeta.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
 	return
 }
 
@@ -373,36 +349,16 @@ func (z *SignedCreateDatabaseResponseHeader) Msgsize() (s int) {
 func (z *SignedDropDatabaseRequestHeader) MarshalHash() (o []byte, err error) {
 	var b []byte
 	o = hsp.Require(b, z.Msgsize())
-	// map header, size 4
-	o = append(o, 0x84, 0x84)
-	if z.Signee == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signee.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
-	o = append(o, 0x84)
-	if z.Signature == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signature.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
+	// map header, size 2
 	// map header, size 1
-	o = append(o, 0x84, 0x81, 0x81)
+	o = append(o, 0x82, 0x82, 0x81, 0x81)
 	if oTemp, err := z.DropDatabaseRequestHeader.DatabaseID.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
 	}
-	o = append(o, 0x84)
-	if oTemp, err := z.Hash.MarshalHash(); err != nil {
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -412,19 +368,7 @@ func (z *SignedDropDatabaseRequestHeader) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *SignedDropDatabaseRequestHeader) Msgsize() (s int) {
-	s = 1 + 7
-	if z.Signee == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signee.Msgsize()
-	}
-	s += 10
-	if z.Signature == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signature.Msgsize()
-	}
-	s += 26 + 1 + 11 + z.DropDatabaseRequestHeader.DatabaseID.Msgsize() + 5 + z.Hash.Msgsize()
+	s = 1 + 26 + 1 + 11 + z.DropDatabaseRequestHeader.DatabaseID.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
 	return
 }
 
@@ -432,36 +376,16 @@ func (z *SignedDropDatabaseRequestHeader) Msgsize() (s int) {
 func (z *SignedGetDatabaseRequestHeader) MarshalHash() (o []byte, err error) {
 	var b []byte
 	o = hsp.Require(b, z.Msgsize())
-	// map header, size 4
-	o = append(o, 0x84, 0x84)
-	if z.Signee == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signee.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
-	o = append(o, 0x84)
-	if z.Signature == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signature.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
+	// map header, size 2
 	// map header, size 1
-	o = append(o, 0x84, 0x81, 0x81)
+	o = append(o, 0x82, 0x82, 0x81, 0x81)
 	if oTemp, err := z.GetDatabaseRequestHeader.DatabaseID.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
 	}
-	o = append(o, 0x84)
-	if oTemp, err := z.Hash.MarshalHash(); err != nil {
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -471,19 +395,7 @@ func (z *SignedGetDatabaseRequestHeader) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *SignedGetDatabaseRequestHeader) Msgsize() (s int) {
-	s = 1 + 7
-	if z.Signee == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signee.Msgsize()
-	}
-	s += 10
-	if z.Signature == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signature.Msgsize()
-	}
-	s += 25 + 1 + 11 + z.GetDatabaseRequestHeader.DatabaseID.Msgsize() + 5 + z.Hash.Msgsize()
+	s = 1 + 25 + 1 + 11 + z.GetDatabaseRequestHeader.DatabaseID.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
 	return
 }
 
@@ -491,36 +403,16 @@ func (z *SignedGetDatabaseRequestHeader) Msgsize() (s int) {
 func (z *SignedGetDatabaseResponseHeader) MarshalHash() (o []byte, err error) {
 	var b []byte
 	o = hsp.Require(b, z.Msgsize())
-	// map header, size 4
-	o = append(o, 0x84, 0x84)
-	if z.Signee == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signee.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
-	o = append(o, 0x84)
-	if z.Signature == nil {
-		o = hsp.AppendNil(o)
-	} else {
-		if oTemp, err := z.Signature.MarshalHash(); err != nil {
-			return nil, err
-		} else {
-			o = hsp.AppendBytes(o, oTemp)
-		}
-	}
+	// map header, size 2
 	// map header, size 1
-	o = append(o, 0x84, 0x81, 0x81)
+	o = append(o, 0x82, 0x82, 0x81, 0x81)
 	if oTemp, err := z.GetDatabaseResponseHeader.InstanceMeta.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
 	}
-	o = append(o, 0x84)
-	if oTemp, err := z.Hash.MarshalHash(); err != nil {
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -530,18 +422,6 @@ func (z *SignedGetDatabaseResponseHeader) MarshalHash() (o []byte, err error) {
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *SignedGetDatabaseResponseHeader) Msgsize() (s int) {
-	s = 1 + 7
-	if z.Signee == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signee.Msgsize()
-	}
-	s += 10
-	if z.Signature == nil {
-		s += hsp.NilSize
-	} else {
-		s += z.Signature.Msgsize()
-	}
-	s += 26 + 1 + 13 + z.GetDatabaseResponseHeader.InstanceMeta.Msgsize() + 5 + z.Hash.Msgsize()
+	s = 1 + 26 + 1 + 13 + z.GetDatabaseResponseHeader.InstanceMeta.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
 	return
 }
diff --git a/blockproducer/db_service_types_gen_test.go b/types/db_service_types_gen_test.go
similarity index 99%
rename from blockproducer/db_service_types_gen_test.go
rename to types/db_service_types_gen_test.go
index b9ad910bd..dca3773e8 100644
--- a/blockproducer/db_service_types_gen_test.go
+++ b/types/db_service_types_gen_test.go
@@ -1,4 +1,4 @@
-package blockproducer
+package types
 
 // Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
 
diff --git a/types/db_service_types_test.go b/types/db_service_types_test.go
new file mode 100644
index 000000000..9cb3cafee
--- /dev/null
+++ b/types/db_service_types_test.go
@@ -0,0 +1,100 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestTypes(t *testing.T) {
+	Convey("test nils", t, func() {
+		priv, _, err := asymmetric.GenSecp256k1KeyPair()
+		So(err, ShouldBeNil)
+
+		h1 := &SignedCreateDatabaseRequestHeader{}
+		err = h1.Sign(priv)
+		So(err, ShouldBeNil)
+		h1.Signee = nil
+		err = h1.Verify()
+		So(err, ShouldNotBeNil)
+
+		h2 := &SignedCreateDatabaseResponseHeader{}
+		err = h2.Sign(priv)
+		So(err, ShouldBeNil)
+		h2.Signee = nil
+		err = h2.Verify()
+		So(err, ShouldNotBeNil)
+
+		h3 := &SignedDropDatabaseRequestHeader{}
+		err = h3.Sign(priv)
+		So(err, ShouldBeNil)
+		h3.Signee = nil
+		err = h3.Verify()
+		So(err, ShouldNotBeNil)
+
+		h4 := &SignedGetDatabaseRequestHeader{}
+		err = h4.Sign(priv)
+		So(err, ShouldBeNil)
+		h4.Signee = nil
+		err = h4.Verify()
+		So(err, ShouldNotBeNil)
+
+		h5 := &SignedGetDatabaseResponseHeader{}
+		err = h5.Sign(priv)
+		So(err, ShouldBeNil)
+		h5.Signee = nil
+		err = h5.Verify()
+		So(err, ShouldNotBeNil)
+	})
+	Convey("test nested sign/verify", t, func() {
+		priv, _, err := asymmetric.GenSecp256k1KeyPair()
+		So(err, ShouldBeNil)
+
+		r1 := &CreateDatabaseRequest{}
+		err = r1.Sign(priv)
+		So(err, ShouldBeNil)
+		err = r1.Verify()
+		So(err, ShouldBeNil)
+
+		r2 := &CreateDatabaseResponse{}
+		err = r2.Sign(priv)
+		So(err, ShouldBeNil)
+		err = r2.Verify()
+		So(err, ShouldBeNil)
+
+		r3 := &DropDatabaseRequest{}
+		err = r3.Sign(priv)
+		So(err, ShouldBeNil)
+		err = r3.Verify()
+		So(err, ShouldBeNil)
+
+		r4 := &GetDatabaseRequest{}
+		err = r4.Sign(priv)
+		So(err, ShouldBeNil)
+		err = r4.Verify()
+		So(err, ShouldBeNil)
+
+		r5 := &GetDatabaseResponse{}
+		err = r5.Sign(priv)
+		So(err, ShouldBeNil)
+		err = r5.Verify()
+		So(err, ShouldBeNil)
+	})
+}
diff --git a/sqlchain/types/doc.go b/types/doc.go
similarity index 100%
rename from sqlchain/types/doc.go
rename to types/doc.go
diff --git a/types/errors.go b/types/errors.go
new file mode 100644
index 000000000..650e46728
--- /dev/null
+++ b/types/errors.go
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"errors"
+)
+
+var (
+	// ErrMerkleRootVerification indicates a failed merkle root verificatin.
+	ErrMerkleRootVerification = errors.New("merkle root verification failed")
+	// ErrNodePublicKeyNotMatch indicates that the public key given with a node does not match the
+	// one in the key store.
+	ErrNodePublicKeyNotMatch = errors.New("node publick key doesn't match")
+	// ErrSignRequest indicates a failed signature compute operation.
+	ErrSignRequest = errors.New("signature compute failed")
+)
diff --git a/types/init_service_type.go b/types/init_service_type.go
new file mode 100644
index 000000000..9d5462788
--- /dev/null
+++ b/types/init_service_type.go
@@ -0,0 +1,84 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+)
+
+//go:generate hsp
+
+// InitService defines worker service init request.
+type InitService struct {
+	proto.Envelope
+}
+
+// ResourceMeta defines single database resource meta.
+type ResourceMeta struct {
+	Node          uint16 // reserved node count
+	Space         uint64 // reserved storage space in bytes
+	Memory        uint64 // reserved memory in bytes
+	LoadAvgPerCPU uint64 // max loadAvg15 per CPU
+	EncryptionKey string `hspack:"-"` // encryption key for database instance
+}
+
+// ServiceInstance defines single instance to be initialized.
+type ServiceInstance struct {
+	DatabaseID   proto.DatabaseID
+	Peers        *proto.Peers
+	ResourceMeta ResourceMeta
+	GenesisBlock *Block
+}
+
+// InitServiceResponseHeader defines worker service init response header.
+type InitServiceResponseHeader struct {
+	Instances []ServiceInstance
+}
+
+// SignedInitServiceResponseHeader defines signed worker service init response header.
+type SignedInitServiceResponseHeader struct {
+	InitServiceResponseHeader
+	verifier.DefaultHashSignVerifierImpl
+}
+
+// InitServiceResponse defines worker service init response.
+type InitServiceResponse struct {
+	Header SignedInitServiceResponseHeader
+}
+
+// Verify checks hash and signature in init service response header.
+func (sh *SignedInitServiceResponseHeader) Verify() (err error) {
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.InitServiceResponseHeader)
+}
+
+// Sign the request.
+func (sh *SignedInitServiceResponseHeader) Sign(signer *asymmetric.PrivateKey) (err error) {
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.InitServiceResponseHeader, signer)
+}
+
+// Verify checks hash and signature in init service response header.
+func (rs *InitServiceResponse) Verify() error {
+	return rs.Header.Verify()
+}
+
+// Sign the request.
+func (rs *InitServiceResponse) Sign(signer *asymmetric.PrivateKey) (err error) {
+	// sign
+	return rs.Header.Sign(signer)
+}
diff --git a/types/init_service_type_gen.go b/types/init_service_type_gen.go
new file mode 100644
index 000000000..f859b2e88
--- /dev/null
+++ b/types/init_service_type_gen.go
@@ -0,0 +1,187 @@
+package types
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	hsp "github.com/CovenantSQL/HashStablePack/marshalhash"
+)
+
+// MarshalHash marshals for hash
+func (z *InitService) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 1
+	o = append(o, 0x81, 0x81)
+	if oTemp, err := z.Envelope.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *InitService) Msgsize() (s int) {
+	s = 1 + 9 + z.Envelope.Msgsize()
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *InitServiceResponse) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 1
+	o = append(o, 0x81, 0x81)
+	if oTemp, err := z.Header.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *InitServiceResponse) Msgsize() (s int) {
+	s = 1 + 7 + z.Header.Msgsize()
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *InitServiceResponseHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 1
+	o = append(o, 0x81, 0x81)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.Instances)))
+	for za0001 := range z.Instances {
+		if oTemp, err := z.Instances[za0001].MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *InitServiceResponseHeader) Msgsize() (s int) {
+	s = 1 + 10 + hsp.ArrayHeaderSize
+	for za0001 := range z.Instances {
+		s += z.Instances[za0001].Msgsize()
+	}
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *ResourceMeta) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 4
+	o = append(o, 0x84, 0x84)
+	o = hsp.AppendUint16(o, z.Node)
+	o = append(o, 0x84)
+	o = hsp.AppendUint64(o, z.Space)
+	o = append(o, 0x84)
+	o = hsp.AppendUint64(o, z.Memory)
+	o = append(o, 0x84)
+	o = hsp.AppendUint64(o, z.LoadAvgPerCPU)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *ResourceMeta) Msgsize() (s int) {
+	s = 1 + 5 + hsp.Uint16Size + 6 + hsp.Uint64Size + 7 + hsp.Uint64Size + 14 + hsp.Uint64Size
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *ServiceInstance) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 4
+	o = append(o, 0x84, 0x84)
+	if z.GenesisBlock == nil {
+		o = hsp.AppendNil(o)
+	} else {
+		if oTemp, err := z.GenesisBlock.MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	o = append(o, 0x84)
+	if z.Peers == nil {
+		o = hsp.AppendNil(o)
+	} else {
+		if oTemp, err := z.Peers.MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	o = append(o, 0x84)
+	if oTemp, err := z.ResourceMeta.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x84)
+	if oTemp, err := z.DatabaseID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *ServiceInstance) Msgsize() (s int) {
+	s = 1 + 13
+	if z.GenesisBlock == nil {
+		s += hsp.NilSize
+	} else {
+		s += z.GenesisBlock.Msgsize()
+	}
+	s += 6
+	if z.Peers == nil {
+		s += hsp.NilSize
+	} else {
+		s += z.Peers.Msgsize()
+	}
+	s += 13 + z.ResourceMeta.Msgsize() + 11 + z.DatabaseID.Msgsize()
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *SignedInitServiceResponseHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	// map header, size 1
+	o = append(o, 0x82, 0x82, 0x81, 0x81)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.InitServiceResponseHeader.Instances)))
+	for za0001 := range z.InitServiceResponseHeader.Instances {
+		if oTemp, err := z.InitServiceResponseHeader.Instances[za0001].MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *SignedInitServiceResponseHeader) Msgsize() (s int) {
+	s = 1 + 26 + 1 + 10 + hsp.ArrayHeaderSize
+	for za0001 := range z.InitServiceResponseHeader.Instances {
+		s += z.InitServiceResponseHeader.Instances[za0001].Msgsize()
+	}
+	s += 28 + z.DefaultHashSignVerifierImpl.Msgsize()
+	return
+}
diff --git a/worker/types/init_service_type_gen_test.go b/types/init_service_type_gen_test.go
similarity index 100%
rename from worker/types/init_service_type_gen_test.go
rename to types/init_service_type_gen_test.go
diff --git a/types/no_ack_report_type.go b/types/no_ack_report_type.go
new file mode 100644
index 000000000..29187a451
--- /dev/null
+++ b/types/no_ack_report_type.go
@@ -0,0 +1,129 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+)
+
+//go:generate hsp
+
+// NoAckReportHeader defines worker issued client no ack report.
+type NoAckReportHeader struct {
+	NodeID    proto.NodeID // reporter node id
+	Timestamp time.Time    // time in UTC zone
+	Response  SignedResponseHeader
+}
+
+// SignedNoAckReportHeader defines worker worker issued/signed client no ack report.
+type SignedNoAckReportHeader struct {
+	NoAckReportHeader
+	verifier.DefaultHashSignVerifierImpl
+}
+
+// NoAckReport defines whole worker no client ack report.
+type NoAckReport struct {
+	proto.Envelope
+	Header SignedNoAckReportHeader
+}
+
+// AggrNoAckReportHeader defines worker leader aggregated client no ack report.
+type AggrNoAckReportHeader struct {
+	NodeID    proto.NodeID              // aggregated report node id
+	Timestamp time.Time                 // time in UTC zone
+	Reports   []SignedNoAckReportHeader // no-ack reports
+	Peers     *proto.Peers              // serving peers during report
+}
+
+// SignedAggrNoAckReportHeader defines worker leader aggregated/signed client no ack report.
+type SignedAggrNoAckReportHeader struct {
+	AggrNoAckReportHeader
+	verifier.DefaultHashSignVerifierImpl
+}
+
+// AggrNoAckReport defines whole worker leader no client ack report.
+type AggrNoAckReport struct {
+	proto.Envelope
+	Header SignedAggrNoAckReportHeader
+}
+
+// Verify checks hash and signature in signed no ack report header.
+func (sh *SignedNoAckReportHeader) Verify() (err error) {
+	// verify original response
+	if err = sh.Response.Verify(); err != nil {
+		return
+	}
+
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.NoAckReportHeader)
+}
+
+// Sign the request.
+func (sh *SignedNoAckReportHeader) Sign(signer *asymmetric.PrivateKey) (err error) {
+	// verify original response
+	if err = sh.Response.Verify(); err != nil {
+		return
+	}
+
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.NoAckReportHeader, signer)
+}
+
+// Verify checks hash and signature in whole no ack report.
+func (r *NoAckReport) Verify() error {
+	return r.Header.Verify()
+}
+
+// Sign the request.
+func (r *NoAckReport) Sign(signer *asymmetric.PrivateKey) error {
+	return r.Header.Sign(signer)
+}
+
+// Verify checks hash and signature in aggregated no ack report.
+func (sh *SignedAggrNoAckReportHeader) Verify() (err error) {
+	// verify original reports
+	for _, r := range sh.Reports {
+		if err = r.Verify(); err != nil {
+			return
+		}
+	}
+
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.AggrNoAckReportHeader)
+}
+
+// Sign the request.
+func (sh *SignedAggrNoAckReportHeader) Sign(signer *asymmetric.PrivateKey) (err error) {
+	for _, r := range sh.Reports {
+		if err = r.Verify(); err != nil {
+			return
+		}
+	}
+
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.AggrNoAckReportHeader, signer)
+}
+
+// Verify the whole aggregation no ack report.
+func (r *AggrNoAckReport) Verify() (err error) {
+	return r.Header.Verify()
+}
+
+// Sign the request.
+func (r *AggrNoAckReport) Sign(signer *asymmetric.PrivateKey) error {
+	return r.Header.Sign(signer)
+}
diff --git a/types/no_ack_report_type_gen.go b/types/no_ack_report_type_gen.go
new file mode 100644
index 000000000..e9e89abc6
--- /dev/null
+++ b/types/no_ack_report_type_gen.go
@@ -0,0 +1,206 @@
+package types
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	hsp "github.com/CovenantSQL/HashStablePack/marshalhash"
+)
+
+// MarshalHash marshals for hash
+func (z *AggrNoAckReport) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	// map header, size 2
+	o = append(o, 0x82, 0x82, 0x82, 0x82)
+	if oTemp, err := z.Header.AggrNoAckReportHeader.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Header.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Envelope.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *AggrNoAckReport) Msgsize() (s int) {
+	s = 1 + 7 + 1 + 22 + z.Header.AggrNoAckReportHeader.Msgsize() + 28 + z.Header.DefaultHashSignVerifierImpl.Msgsize() + 9 + z.Envelope.Msgsize()
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *AggrNoAckReportHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 4
+	o = append(o, 0x84, 0x84)
+	if z.Peers == nil {
+		o = hsp.AppendNil(o)
+	} else {
+		if oTemp, err := z.Peers.MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	o = append(o, 0x84)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.Reports)))
+	for za0001 := range z.Reports {
+		if oTemp, err := z.Reports[za0001].MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	o = append(o, 0x84)
+	if oTemp, err := z.NodeID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x84)
+	o = hsp.AppendTime(o, z.Timestamp)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *AggrNoAckReportHeader) Msgsize() (s int) {
+	s = 1 + 6
+	if z.Peers == nil {
+		s += hsp.NilSize
+	} else {
+		s += z.Peers.Msgsize()
+	}
+	s += 8 + hsp.ArrayHeaderSize
+	for za0001 := range z.Reports {
+		s += z.Reports[za0001].Msgsize()
+	}
+	s += 7 + z.NodeID.Msgsize() + 10 + hsp.TimeSize
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *NoAckReport) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	if oTemp, err := z.Header.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Envelope.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *NoAckReport) Msgsize() (s int) {
+	s = 1 + 7 + z.Header.Msgsize() + 9 + z.Envelope.Msgsize()
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *NoAckReportHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 3
+	o = append(o, 0x83, 0x83)
+	if oTemp, err := z.Response.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x83)
+	if oTemp, err := z.NodeID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x83)
+	o = hsp.AppendTime(o, z.Timestamp)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *NoAckReportHeader) Msgsize() (s int) {
+	s = 1 + 9 + z.Response.Msgsize() + 7 + z.NodeID.Msgsize() + 10 + hsp.TimeSize
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *SignedAggrNoAckReportHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	if oTemp, err := z.AggrNoAckReportHeader.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *SignedAggrNoAckReportHeader) Msgsize() (s int) {
+	s = 1 + 22 + z.AggrNoAckReportHeader.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *SignedNoAckReportHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	// map header, size 3
+	o = append(o, 0x82, 0x82, 0x83, 0x83)
+	if oTemp, err := z.NoAckReportHeader.NodeID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x83)
+	o = hsp.AppendTime(o, z.NoAckReportHeader.Timestamp)
+	o = append(o, 0x83)
+	if oTemp, err := z.NoAckReportHeader.Response.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *SignedNoAckReportHeader) Msgsize() (s int) {
+	s = 1 + 18 + 1 + 7 + z.NoAckReportHeader.NodeID.Msgsize() + 10 + hsp.TimeSize + 9 + z.NoAckReportHeader.Response.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
+	return
+}
diff --git a/worker/types/no_ack_report_type_gen_test.go b/types/no_ack_report_type_gen_test.go
similarity index 100%
rename from worker/types/no_ack_report_type_gen_test.go
rename to types/no_ack_report_type_gen_test.go
diff --git a/sqlchain/types/observer.go b/types/observer.go
similarity index 100%
rename from sqlchain/types/observer.go
rename to types/observer.go
diff --git a/types/request_type.go b/types/request_type.go
new file mode 100644
index 000000000..2105e641c
--- /dev/null
+++ b/types/request_type.go
@@ -0,0 +1,147 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+)
+
+//go:generate hsp
+
+// QueryType enumerates available query type, currently read/write.
+type QueryType int32
+
+const (
+	// ReadQuery defines a read query type.
+	ReadQuery QueryType = iota
+	// WriteQuery defines a write query type.
+	WriteQuery
+)
+
+// NamedArg defines the named argument structure for database.
+type NamedArg struct {
+	Name  string
+	Value interface{}
+}
+
+// Query defines single query.
+type Query struct {
+	Pattern string
+	Args    []NamedArg
+}
+
+// RequestPayload defines a queries payload.
+type RequestPayload struct {
+	Queries []Query `json:"qs"`
+}
+
+// RequestHeader defines a query request header.
+type RequestHeader struct {
+	QueryType    QueryType        `json:"qt"`
+	NodeID       proto.NodeID     `json:"id"`   // request node id
+	DatabaseID   proto.DatabaseID `json:"dbid"` // request database id
+	ConnectionID uint64           `json:"cid"`
+	SeqNo        uint64           `json:"seq"`
+	Timestamp    time.Time        `json:"t"`  // time in UTC zone
+	BatchCount   uint64           `json:"bc"` // query count in this request
+	QueriesHash  hash.Hash        `json:"qh"` // hash of query payload
+}
+
+// QueryKey defines an unique query key of a request.
+type QueryKey struct {
+	NodeID       proto.NodeID `json:"id"`
+	ConnectionID uint64       `json:"cid"`
+	SeqNo        uint64       `json:"seq"`
+}
+
+// String implements fmt.Stringer for logging purpose.
+func (k *QueryKey) String() string {
+	return fmt.Sprintf("%s#%016x#%016x", string(k.NodeID[:8]), k.ConnectionID, k.SeqNo)
+}
+
+// SignedRequestHeader defines a signed query request header.
+type SignedRequestHeader struct {
+	RequestHeader
+	verifier.DefaultHashSignVerifierImpl
+}
+
+// Request defines a complete query request.
+type Request struct {
+	proto.Envelope
+	Header  SignedRequestHeader `json:"h"`
+	Payload RequestPayload      `json:"p"`
+}
+
+// String implements fmt.Stringer for logging purpose.
+func (t QueryType) String() string {
+	switch t {
+	case ReadQuery:
+		return "read"
+	case WriteQuery:
+		return "write"
+	default:
+		return "unknown"
+	}
+}
+
+// Verify checks hash and signature in request header.
+func (sh *SignedRequestHeader) Verify() (err error) {
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.RequestHeader)
+}
+
+// Sign the request.
+func (sh *SignedRequestHeader) Sign(signer *asymmetric.PrivateKey) (err error) {
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.RequestHeader, signer)
+}
+
+// Verify checks hash and signature in whole request.
+func (r *Request) Verify() (err error) {
+	// verify payload hash in signed header
+	if err = verifyHash(&r.Payload, &r.Header.QueriesHash); err != nil {
+		return
+	}
+	// verify header sign
+	return r.Header.Verify()
+}
+
+// Sign the request.
+func (r *Request) Sign(signer *asymmetric.PrivateKey) (err error) {
+	// set query count
+	r.Header.BatchCount = uint64(len(r.Payload.Queries))
+
+	// compute payload hash
+	if err = buildHash(&r.Payload, &r.Header.QueriesHash); err != nil {
+		return
+	}
+
+	return r.Header.Sign(signer)
+}
+
+// GetQueryKey returns a unique query key of this request.
+func (sh *SignedRequestHeader) GetQueryKey() QueryKey {
+	return QueryKey{
+		NodeID:       sh.NodeID,
+		ConnectionID: sh.ConnectionID,
+		SeqNo:        sh.SeqNo,
+	}
+}
diff --git a/types/request_type_gen.go b/types/request_type_gen.go
new file mode 100644
index 000000000..709e66bb9
--- /dev/null
+++ b/types/request_type_gen.go
@@ -0,0 +1,239 @@
+package types
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	hsp "github.com/CovenantSQL/HashStablePack/marshalhash"
+)
+
+// MarshalHash marshals for hash
+func (z NamedArg) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	o, err = hsp.AppendIntf(o, z.Value)
+	if err != nil {
+		return
+	}
+	o = append(o, 0x82)
+	o = hsp.AppendString(o, z.Name)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z NamedArg) Msgsize() (s int) {
+	s = 1 + 6 + hsp.GuessSize(z.Value) + 5 + hsp.StringPrefixSize + len(z.Name)
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *Query) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.Args)))
+	for za0001 := range z.Args {
+		// map header, size 2
+		o = append(o, 0x82, 0x82)
+		o = hsp.AppendString(o, z.Args[za0001].Name)
+		o = append(o, 0x82)
+		o, err = hsp.AppendIntf(o, z.Args[za0001].Value)
+		if err != nil {
+			return
+		}
+	}
+	o = append(o, 0x82)
+	o = hsp.AppendString(o, z.Pattern)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *Query) Msgsize() (s int) {
+	s = 1 + 5 + hsp.ArrayHeaderSize
+	for za0001 := range z.Args {
+		s += 1 + 5 + hsp.StringPrefixSize + len(z.Args[za0001].Name) + 6 + hsp.GuessSize(z.Args[za0001].Value)
+	}
+	s += 8 + hsp.StringPrefixSize + len(z.Pattern)
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *QueryKey) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 3
+	o = append(o, 0x83, 0x83)
+	if oTemp, err := z.NodeID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x83)
+	o = hsp.AppendUint64(o, z.ConnectionID)
+	o = append(o, 0x83)
+	o = hsp.AppendUint64(o, z.SeqNo)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *QueryKey) Msgsize() (s int) {
+	s = 1 + 7 + z.NodeID.Msgsize() + 13 + hsp.Uint64Size + 6 + hsp.Uint64Size
+	return
+}
+
+// MarshalHash marshals for hash
+func (z QueryType) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	o = hsp.AppendInt32(o, int32(z))
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z QueryType) Msgsize() (s int) {
+	s = hsp.Int32Size
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *Request) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 3
+	// map header, size 1
+	o = append(o, 0x83, 0x83, 0x81, 0x81)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.Payload.Queries)))
+	for za0001 := range z.Payload.Queries {
+		if oTemp, err := z.Payload.Queries[za0001].MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	// map header, size 2
+	o = append(o, 0x83, 0x82, 0x82)
+	if oTemp, err := z.Header.RequestHeader.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Header.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x83)
+	if oTemp, err := z.Envelope.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *Request) Msgsize() (s int) {
+	s = 1 + 8 + 1 + 8 + hsp.ArrayHeaderSize
+	for za0001 := range z.Payload.Queries {
+		s += z.Payload.Queries[za0001].Msgsize()
+	}
+	s += 7 + 1 + 14 + z.Header.RequestHeader.Msgsize() + 28 + z.Header.DefaultHashSignVerifierImpl.Msgsize() + 9 + z.Envelope.Msgsize()
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *RequestHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 8
+	o = append(o, 0x88, 0x88)
+	o = hsp.AppendInt32(o, int32(z.QueryType))
+	o = append(o, 0x88)
+	if oTemp, err := z.QueriesHash.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x88)
+	if oTemp, err := z.DatabaseID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x88)
+	if oTemp, err := z.NodeID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x88)
+	o = hsp.AppendTime(o, z.Timestamp)
+	o = append(o, 0x88)
+	o = hsp.AppendUint64(o, z.ConnectionID)
+	o = append(o, 0x88)
+	o = hsp.AppendUint64(o, z.SeqNo)
+	o = append(o, 0x88)
+	o = hsp.AppendUint64(o, z.BatchCount)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *RequestHeader) Msgsize() (s int) {
+	s = 1 + 10 + hsp.Int32Size + 12 + z.QueriesHash.Msgsize() + 11 + z.DatabaseID.Msgsize() + 7 + z.NodeID.Msgsize() + 10 + hsp.TimeSize + 13 + hsp.Uint64Size + 6 + hsp.Uint64Size + 11 + hsp.Uint64Size
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *RequestPayload) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 1
+	o = append(o, 0x81, 0x81)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.Queries)))
+	for za0001 := range z.Queries {
+		if oTemp, err := z.Queries[za0001].MarshalHash(); err != nil {
+			return nil, err
+		} else {
+			o = hsp.AppendBytes(o, oTemp)
+		}
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *RequestPayload) Msgsize() (s int) {
+	s = 1 + 8 + hsp.ArrayHeaderSize
+	for za0001 := range z.Queries {
+		s += z.Queries[za0001].Msgsize()
+	}
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *SignedRequestHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	if oTemp, err := z.RequestHeader.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *SignedRequestHeader) Msgsize() (s int) {
+	s = 1 + 14 + z.RequestHeader.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
+	return
+}
diff --git a/worker/types/request_type_gen_test.go b/types/request_type_gen_test.go
similarity index 100%
rename from worker/types/request_type_gen_test.go
rename to types/request_type_gen_test.go
diff --git a/types/response_type.go b/types/response_type.go
new file mode 100644
index 000000000..968385eca
--- /dev/null
+++ b/types/response_type.go
@@ -0,0 +1,110 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/pkg/errors"
+)
+
+//go:generate hsp
+
+// ResponseRow defines single row of query response.
+type ResponseRow struct {
+	Values []interface{}
+}
+
+// ResponsePayload defines column names and rows of query response.
+type ResponsePayload struct {
+	Columns   []string      `json:"c"`
+	DeclTypes []string      `json:"t"`
+	Rows      []ResponseRow `json:"r"`
+}
+
+// ResponseHeader defines a query response header.
+type ResponseHeader struct {
+	Request      SignedRequestHeader `json:"r"`
+	NodeID       proto.NodeID        `json:"id"` // response node id
+	Timestamp    time.Time           `json:"t"`  // time in UTC zone
+	RowCount     uint64              `json:"c"`  // response row count of payload
+	LogOffset    uint64              `json:"o"`  // request log offset
+	LastInsertID int64               `json:"l"`  // insert insert id
+	AffectedRows int64               `json:"a"`  // affected rows
+	PayloadHash  hash.Hash           `json:"dh"` // hash of query response payload
+}
+
+// SignedResponseHeader defines a signed query response header.
+type SignedResponseHeader struct {
+	ResponseHeader
+	verifier.DefaultHashSignVerifierImpl
+}
+
+// Response defines a complete query response.
+type Response struct {
+	Header  SignedResponseHeader `json:"h"`
+	Payload ResponsePayload      `json:"p"`
+}
+
+// Verify checks hash and signature in response header.
+func (sh *SignedResponseHeader) Verify() (err error) {
+	// verify original request header
+	if err = sh.Request.Verify(); err != nil {
+		return
+	}
+
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.ResponseHeader)
+}
+
+// Sign the request.
+func (sh *SignedResponseHeader) Sign(signer *asymmetric.PrivateKey) (err error) {
+	// make sure original header is signed
+	if err = sh.Request.Verify(); err != nil {
+		err = errors.Wrapf(err, "SignedResponseHeader %v", sh)
+		return
+	}
+
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.ResponseHeader, signer)
+}
+
+// Verify checks hash and signature in whole response.
+func (sh *Response) Verify() (err error) {
+	// verify data hash in header
+	if err = verifyHash(&sh.Payload, &sh.Header.PayloadHash); err != nil {
+		return
+	}
+
+	return sh.Header.Verify()
+}
+
+// Sign the request.
+func (sh *Response) Sign(signer *asymmetric.PrivateKey) (err error) {
+	// set rows count
+	sh.Header.RowCount = uint64(len(sh.Payload.Rows))
+
+	// build hash in header
+	if err = buildHash(&sh.Payload, &sh.Header.PayloadHash); err != nil {
+		return
+	}
+
+	// sign the request
+	return sh.Header.Sign(signer)
+}
diff --git a/types/response_type_gen.go b/types/response_type_gen.go
new file mode 100644
index 000000000..78c9db9c3
--- /dev/null
+++ b/types/response_type_gen.go
@@ -0,0 +1,184 @@
+package types
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	hsp "github.com/CovenantSQL/HashStablePack/marshalhash"
+)
+
+// MarshalHash marshals for hash
+func (z *Response) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	if oTemp, err := z.Payload.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	// map header, size 2
+	o = append(o, 0x82, 0x82, 0x82)
+	if oTemp, err := z.Header.ResponseHeader.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Header.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *Response) Msgsize() (s int) {
+	s = 1 + 8 + z.Payload.Msgsize() + 7 + 1 + 15 + z.Header.ResponseHeader.Msgsize() + 28 + z.Header.DefaultHashSignVerifierImpl.Msgsize()
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *ResponseHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 8
+	o = append(o, 0x88, 0x88)
+	if oTemp, err := z.Request.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x88)
+	if oTemp, err := z.PayloadHash.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x88)
+	o = hsp.AppendInt64(o, z.LastInsertID)
+	o = append(o, 0x88)
+	o = hsp.AppendInt64(o, z.AffectedRows)
+	o = append(o, 0x88)
+	if oTemp, err := z.NodeID.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x88)
+	o = hsp.AppendTime(o, z.Timestamp)
+	o = append(o, 0x88)
+	o = hsp.AppendUint64(o, z.RowCount)
+	o = append(o, 0x88)
+	o = hsp.AppendUint64(o, z.LogOffset)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *ResponseHeader) Msgsize() (s int) {
+	s = 1 + 8 + z.Request.Msgsize() + 12 + z.PayloadHash.Msgsize() + 13 + hsp.Int64Size + 13 + hsp.Int64Size + 7 + z.NodeID.Msgsize() + 10 + hsp.TimeSize + 9 + hsp.Uint64Size + 10 + hsp.Uint64Size
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *ResponsePayload) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 3
+	o = append(o, 0x83, 0x83)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.Rows)))
+	for za0003 := range z.Rows {
+		// map header, size 1
+		o = append(o, 0x81, 0x81)
+		o = hsp.AppendArrayHeader(o, uint32(len(z.Rows[za0003].Values)))
+		for za0004 := range z.Rows[za0003].Values {
+			o, err = hsp.AppendIntf(o, z.Rows[za0003].Values[za0004])
+			if err != nil {
+				return
+			}
+		}
+	}
+	o = append(o, 0x83)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.Columns)))
+	for za0001 := range z.Columns {
+		o = hsp.AppendString(o, z.Columns[za0001])
+	}
+	o = append(o, 0x83)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.DeclTypes)))
+	for za0002 := range z.DeclTypes {
+		o = hsp.AppendString(o, z.DeclTypes[za0002])
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *ResponsePayload) Msgsize() (s int) {
+	s = 1 + 5 + hsp.ArrayHeaderSize
+	for za0003 := range z.Rows {
+		s += 1 + 7 + hsp.ArrayHeaderSize
+		for za0004 := range z.Rows[za0003].Values {
+			s += hsp.GuessSize(z.Rows[za0003].Values[za0004])
+		}
+	}
+	s += 8 + hsp.ArrayHeaderSize
+	for za0001 := range z.Columns {
+		s += hsp.StringPrefixSize + len(z.Columns[za0001])
+	}
+	s += 10 + hsp.ArrayHeaderSize
+	for za0002 := range z.DeclTypes {
+		s += hsp.StringPrefixSize + len(z.DeclTypes[za0002])
+	}
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *ResponseRow) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 1
+	o = append(o, 0x81, 0x81)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.Values)))
+	for za0001 := range z.Values {
+		o, err = hsp.AppendIntf(o, z.Values[za0001])
+		if err != nil {
+			return
+		}
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *ResponseRow) Msgsize() (s int) {
+	s = 1 + 7 + hsp.ArrayHeaderSize
+	for za0001 := range z.Values {
+		s += hsp.GuessSize(z.Values[za0001])
+	}
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *SignedResponseHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	if oTemp, err := z.ResponseHeader.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *SignedResponseHeader) Msgsize() (s int) {
+	s = 1 + 15 + z.ResponseHeader.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
+	return
+}
diff --git a/worker/types/response_type_gen_test.go b/types/response_type_gen_test.go
similarity index 100%
rename from worker/types/response_type_gen_test.go
rename to types/response_type_gen_test.go
diff --git a/types/types.proto b/types/types.proto
deleted file mode 100644
index a2abe9f05..000000000
--- a/types/types.proto
+++ /dev/null
@@ -1,112 +0,0 @@
-syntax = "proto3";
-package types;
-
-message Signature {
-    string R = 1;
-    string S = 2;
-}
-
-message PublicKey {
-    bytes PublicKey = 1;
-}
-
-message Hash {
-    bytes Hash = 1;
-}
-
-message UtxoEntry {
-    bool IsCoinbase = 1;
-    bool FromMainChain = 2;
-    uint32 BlockHeight = 3;
-    map<uint32, Utxo> SparseOutputs = 4;
-}
-
-message Utxo {
-    UtxoHeader UtxoHeader = 1;
-    bool Spent = 2;
-    uint64 amount = 3;
-}
-
-message UtxoHeader {
-    int32 Version = 1;
-    Hash PrevTxHash = 2;
-    PublicKey Signee = 3;
-    Signature Signature = 4;
-}
-
-enum TxType {
-     QUERY = 0;
-     STORAGE = 1;
-}
-
-message Tx {
-    repeated Utxo UtxoIn = 1;
-    repeated Utxo UtxoOut = 2;
-    TxType type = 3;
-    string Content = 4;
-}
-
-message NodeID {
-    string NodeID = 1;
-}
-
-message AccountAddress {
-    string AccountAddress = 1;
-}
-
-message Header {
-    int32 Version = 1;
-    NodeID Producer = 2;
-    Hash Root = 3;
-    Hash Parent = 4;
-    Hash MerkleRoot = 5;
-    int64 Timestamp = 6;
-}
-
-message SignedHeader {
-    Header Header = 1;
-    Hash BlockHash = 2;
-    PublicKey Signee = 3;
-    Signature Signature = 4;
-}
-
-message State {
-    Hash Head = 1;
-    int32 Height = 2;
-}
-
-message BPTx {
-    Hash TxHash = 1;
-    BPTxData TxData = 2;
-}
-
-message BPTxData {
-    uint64 AccountNonce = 1;
-    AccountAddress Recipient = 2;
-    bytes Amount = 3;
-    bytes Payload = 4;
-
-    Signature Signature = 5;
-    PublicKey Signee = 6;
-}
-
-message BPHeader {
-    int32 Version = 1;
-    AccountAddress Producer = 2;
-    Hash Root = 3;
-    Hash Parent = 4;
-    Hash MerkleRoot = 5;
-    int64 Timestamp = 6;
-}
-
-message BPSignedHeader {
-    BPHeader Header = 1;
-    Hash BlockHash = 2;
-    PublicKey Signee = 3;
-    Signature Signature = 4;
-}
-
-message BPBlock {
-    BPSignedHeader Header = 1;
-    repeated BPTx Tx = 2;
-}
diff --git a/types/types_test.go b/types/types_test.go
new file mode 100644
index 000000000..39960d09d
--- /dev/null
+++ b/types/types_test.go
@@ -0,0 +1,692 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/utils"
+	"github.com/pkg/errors"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func getCommKeys() (*asymmetric.PrivateKey, *asymmetric.PublicKey) {
+	testPriv := []byte{
+		0xea, 0xf0, 0x2c, 0xa3, 0x48, 0xc5, 0x24, 0xe6,
+		0x39, 0x26, 0x55, 0xba, 0x4d, 0x29, 0x60, 0x3c,
+		0xd1, 0xa7, 0x34, 0x7d, 0x9d, 0x65, 0xcf, 0xe9,
+		0x3c, 0xe1, 0xeb, 0xff, 0xdc, 0xa2, 0x26, 0x94,
+	}
+	return asymmetric.PrivKeyFromBytes(testPriv)
+}
+
+func TestSignedRequestHeader_Sign(t *testing.T) {
+	privKey, _ := getCommKeys()
+
+	Convey("sign", t, func() {
+		req := &SignedRequestHeader{
+			RequestHeader: RequestHeader{
+				QueryType:    WriteQuery,
+				NodeID:       proto.NodeID("node"),
+				DatabaseID:   proto.DatabaseID("db1"),
+				ConnectionID: uint64(1),
+				SeqNo:        uint64(2),
+				Timestamp:    time.Now().UTC(),
+			},
+		}
+
+		var err error
+
+		err = req.Sign(privKey)
+		So(err, ShouldBeNil)
+
+		Convey("verify", func() {
+			err = req.Verify()
+			So(err, ShouldBeNil)
+
+			// modify structure
+			req.Timestamp = req.Timestamp.Add(time.Second)
+
+			err = req.Verify()
+			So(err, ShouldNotBeNil)
+
+			s, err := req.MarshalHash()
+			So(err, ShouldBeNil)
+			So(s, ShouldNotBeEmpty)
+		})
+	})
+}
+
+func TestRequest_Sign(t *testing.T) {
+	privKey, _ := getCommKeys()
+
+	Convey("sign", t, func() {
+		req := &Request{
+			Header: SignedRequestHeader{
+				RequestHeader: RequestHeader{
+					QueryType:    WriteQuery,
+					NodeID:       proto.NodeID("node"),
+					DatabaseID:   proto.DatabaseID("db1"),
+					ConnectionID: uint64(1),
+					SeqNo:        uint64(2),
+					Timestamp:    time.Now().UTC(),
+				},
+			},
+			Payload: RequestPayload{
+				Queries: []Query{
+					{
+						Pattern: "INSERT INTO test VALUES(?)",
+						Args: []NamedArg{
+							{
+								Value: 1,
+							},
+						},
+					},
+					{
+						Pattern: "INSERT INTO test VALUES(?)",
+						Args: []NamedArg{
+							{
+								Value: "happy",
+							},
+						},
+					},
+				},
+			},
+		}
+
+		var err error
+
+		// sign
+		err = req.Sign(privKey)
+		So(err, ShouldBeNil)
+		So(req.Header.BatchCount, ShouldEqual, uint64(len(req.Payload.Queries)))
+
+		// test queries hash
+		err = verifyHash(&req.Payload, &req.Header.QueriesHash)
+		So(err, ShouldBeNil)
+
+		Convey("verify", func() {
+			err = req.Verify()
+			So(err, ShouldBeNil)
+
+			Convey("header change", func() {
+				// modify structure
+				req.Header.Timestamp = req.Header.Timestamp.Add(time.Second)
+
+				err = req.Verify()
+				So(err, ShouldNotBeNil)
+			})
+
+			Convey("header change with invalid queries hash", func() {
+				req.Payload.Queries = append(req.Payload.Queries,
+					Query{
+						Pattern: "select 1",
+					},
+				)
+
+				err = req.Verify()
+				So(err, ShouldNotBeNil)
+			})
+		})
+	})
+}
+
+func TestResponse_Sign(t *testing.T) {
+	privKey, _ := getCommKeys()
+
+	Convey("sign", t, func() {
+		res := &Response{
+			Header: SignedResponseHeader{
+				ResponseHeader: ResponseHeader{
+					Request: SignedRequestHeader{
+						RequestHeader: RequestHeader{
+							QueryType:    WriteQuery,
+							NodeID:       proto.NodeID("0000000000000000000000000000000000000000000000000000000000001111"),
+							DatabaseID:   proto.DatabaseID("db1"),
+							ConnectionID: uint64(1),
+							SeqNo:        uint64(2),
+							Timestamp:    time.Now().UTC(),
+						},
+					},
+					NodeID:    proto.NodeID("0000000000000000000000000000000000000000000000000000000000002222"),
+					Timestamp: time.Now().UTC(),
+					RowCount:  uint64(1),
+				},
+			},
+			Payload: ResponsePayload{
+				Columns: []string{
+					"test_integer",
+					"test_boolean",
+					"test_time",
+					"test_nil",
+					"test_float",
+					"test_binary_string",
+					"test_string",
+					"test_empty_time",
+				},
+				DeclTypes: []string{
+					"INTEGER",
+					"BOOLEAN",
+					"DATETIME",
+					"INTEGER",
+					"FLOAT",
+					"BLOB",
+					"TEXT",
+					"DATETIME",
+				},
+				Rows: []ResponseRow{
+					{
+						Values: []interface{}{
+							int(1),
+							true,
+							time.Now().UTC(),
+							nil,
+							float64(1.0001),
+							"11111\0001111111",
+							"11111111111111",
+							time.Time{},
+						},
+					},
+				},
+			},
+		}
+
+		var err error
+
+		// sign directly, embedded original request is not filled
+		err = res.Sign(privKey)
+		So(err, ShouldNotBeNil)
+		So(errors.Cause(err), ShouldBeIn, []error{
+			verifier.ErrHashValueNotMatch,
+			verifier.ErrSignatureNotMatch,
+		})
+
+		// sign original request first
+		err = res.Header.Request.Sign(privKey)
+		So(err, ShouldBeNil)
+
+		// sign again
+		err = res.Sign(privKey)
+		So(err, ShouldBeNil)
+
+		// test hash
+		err = verifyHash(&res.Payload, &res.Header.PayloadHash)
+		So(err, ShouldBeNil)
+
+		// verify
+		Convey("verify", func() {
+			err = res.Verify()
+			So(err, ShouldBeNil)
+
+			Convey("encode/decode verify", func() {
+				buf, err := utils.EncodeMsgPack(res)
+				So(err, ShouldBeNil)
+				var r *Response
+				err = utils.DecodeMsgPack(buf.Bytes(), &r)
+				So(err, ShouldBeNil)
+				err = r.Verify()
+				So(err, ShouldBeNil)
+			})
+			Convey("request change", func() {
+				res.Header.Request.BatchCount = 200
+
+				err = res.Verify()
+				So(err, ShouldNotBeNil)
+			})
+			Convey("payload change", func() {
+				res.Payload.DeclTypes[0] = "INT"
+
+				err = res.Verify()
+				So(err, ShouldNotBeNil)
+			})
+			Convey("header change", func() {
+				res.Header.Timestamp = res.Header.Timestamp.Add(time.Second)
+
+				err = res.Verify()
+				So(err, ShouldNotBeNil)
+			})
+		})
+	})
+}
+
+func TestAck_Sign(t *testing.T) {
+	privKey, _ := getCommKeys()
+
+	Convey("sign", t, func() {
+		ack := &Ack{
+			Header: SignedAckHeader{
+				AckHeader: AckHeader{
+					Response: SignedResponseHeader{
+						ResponseHeader: ResponseHeader{
+							Request: SignedRequestHeader{
+								RequestHeader: RequestHeader{
+									QueryType:    WriteQuery,
+									NodeID:       proto.NodeID("0000000000000000000000000000000000000000000000000000000000001111"),
+									DatabaseID:   proto.DatabaseID("db1"),
+									ConnectionID: uint64(1),
+									SeqNo:        uint64(2),
+									Timestamp:    time.Now().UTC(),
+								},
+							},
+							NodeID:    proto.NodeID("0000000000000000000000000000000000000000000000000000000000002222"),
+							Timestamp: time.Now().UTC(),
+							RowCount:  uint64(1),
+						},
+					},
+					NodeID:    proto.NodeID("0000000000000000000000000000000000000000000000000000000000001111"),
+					Timestamp: time.Now().UTC(),
+				},
+			},
+		}
+
+		var err error
+
+		Convey("get query key", func() {
+			key := ack.Header.SignedRequestHeader().GetQueryKey()
+			So(key.NodeID, ShouldEqual, ack.Header.SignedRequestHeader().NodeID)
+			So(key.ConnectionID, ShouldEqual, ack.Header.SignedRequestHeader().ConnectionID)
+			So(key.SeqNo, ShouldEqual, ack.Header.SignedRequestHeader().SeqNo)
+		})
+
+		// sign directly, embedded original response is not filled
+		err = ack.Sign(privKey, false)
+		So(err, ShouldBeNil)
+		err = ack.Sign(privKey, true)
+		So(err, ShouldNotBeNil)
+		So(errors.Cause(err), ShouldBeIn, []error{
+			verifier.ErrHashValueNotMatch,
+			verifier.ErrSignatureNotMatch,
+		})
+
+		// sign nested structure, step by step
+		// this is not required during runtime
+		// during runtime, nested structures is signed and provided by peers
+		err = ack.Header.Response.Request.Sign(privKey)
+		So(err, ShouldBeNil)
+		err = ack.Header.Response.Sign(privKey)
+		So(err, ShouldBeNil)
+		err = ack.Sign(privKey, true)
+		So(err, ShouldBeNil)
+
+		Convey("verify", func() {
+			err = ack.Verify()
+			So(err, ShouldBeNil)
+
+			Convey("request change", func() {
+				ack.Header.Response.Request.QueryType = ReadQuery
+
+				err = ack.Verify()
+				So(err, ShouldNotBeNil)
+			})
+			Convey("response change", func() {
+				ack.Header.Response.RowCount = 100
+
+				err = ack.Verify()
+				So(err, ShouldNotBeNil)
+			})
+			Convey("header change", func() {
+				ack.Header.Timestamp = ack.Header.Timestamp.Add(time.Second)
+
+				err = ack.Verify()
+				So(err, ShouldNotBeNil)
+			})
+		})
+	})
+}
+
+func TestNoAckReport_Sign(t *testing.T) {
+	privKey, _ := getCommKeys()
+
+	Convey("sign", t, func() {
+		noAck := &NoAckReport{
+			Header: SignedNoAckReportHeader{
+				NoAckReportHeader: NoAckReportHeader{
+					NodeID:    proto.NodeID("0000000000000000000000000000000000000000000000000000000000002222"),
+					Timestamp: time.Now().UTC(),
+					Response: SignedResponseHeader{
+						ResponseHeader: ResponseHeader{
+							Request: SignedRequestHeader{
+								RequestHeader: RequestHeader{
+									QueryType:    WriteQuery,
+									NodeID:       proto.NodeID("0000000000000000000000000000000000000000000000000000000000001111"),
+									DatabaseID:   proto.DatabaseID("db1"),
+									ConnectionID: uint64(1),
+									SeqNo:        uint64(2),
+									Timestamp:    time.Now().UTC(),
+								},
+							},
+							NodeID:    proto.NodeID("0000000000000000000000000000000000000000000000000000000000002222"),
+							Timestamp: time.Now().UTC(),
+							RowCount:  uint64(1),
+						},
+					},
+				},
+			},
+		}
+
+		var err error
+
+		// sign directly, embedded original response/request is not filled
+		err = noAck.Sign(privKey)
+		So(err, ShouldNotBeNil)
+		So(errors.Cause(err), ShouldBeIn, []error{
+			verifier.ErrHashValueNotMatch,
+			verifier.ErrSignatureNotMatch,
+		})
+
+		// sign nested structure
+		err = noAck.Header.Response.Request.Sign(privKey)
+		So(err, ShouldBeNil)
+		err = noAck.Header.Response.Sign(privKey)
+		So(err, ShouldBeNil)
+		err = noAck.Sign(privKey)
+		So(err, ShouldBeNil)
+
+		Convey("verify", func() {
+			err = noAck.Verify()
+			So(err, ShouldBeNil)
+
+			Convey("request change", func() {
+				noAck.Header.Response.Request.QueryType = ReadQuery
+
+				err = noAck.Verify()
+				So(err, ShouldNotBeNil)
+			})
+
+			Convey("response change", func() {
+				noAck.Header.Response.RowCount = 100
+
+				err = noAck.Verify()
+				So(err, ShouldNotBeNil)
+			})
+
+			Convey("header change", func() {
+				noAck.Header.Timestamp = noAck.Header.Timestamp.Add(time.Second)
+
+				err = noAck.Verify()
+				So(err, ShouldNotBeNil)
+			})
+		})
+	})
+}
+
+func TestAggrNoAckReport_Sign(t *testing.T) {
+	privKey, _ := getCommKeys()
+
+	Convey("sign", t, func() {
+		aggrNoAck := &AggrNoAckReport{
+			Header: SignedAggrNoAckReportHeader{
+				AggrNoAckReportHeader: AggrNoAckReportHeader{
+					NodeID:    proto.NodeID("0000000000000000000000000000000000000000000000000000000000003333"),
+					Timestamp: time.Now().UTC(),
+					Reports: []SignedNoAckReportHeader{
+						{
+							NoAckReportHeader: NoAckReportHeader{
+								NodeID:    proto.NodeID("0000000000000000000000000000000000000000000000000000000000002222"),
+								Timestamp: time.Now().UTC(),
+								Response: SignedResponseHeader{
+									ResponseHeader: ResponseHeader{
+										Request: SignedRequestHeader{
+											RequestHeader: RequestHeader{
+												QueryType:    WriteQuery,
+												NodeID:       proto.NodeID("0000000000000000000000000000000000000000000000000000000000001111"),
+												DatabaseID:   proto.DatabaseID("db1"),
+												ConnectionID: uint64(1),
+												SeqNo:        uint64(2),
+												Timestamp:    time.Now().UTC(),
+											},
+										},
+										NodeID:    proto.NodeID("0000000000000000000000000000000000000000000000000000000000002222"),
+										Timestamp: time.Now().UTC(),
+										RowCount:  uint64(1),
+									},
+								},
+							},
+						},
+						{
+							NoAckReportHeader: NoAckReportHeader{
+								NodeID:    proto.NodeID("0000000000000000000000000000000000000000000000000000000000003333"),
+								Timestamp: time.Now().UTC(),
+								Response: SignedResponseHeader{
+									ResponseHeader: ResponseHeader{
+										Request: SignedRequestHeader{
+											RequestHeader: RequestHeader{
+												QueryType:    WriteQuery,
+												NodeID:       proto.NodeID("0000000000000000000000000000000000000000000000000000000000001111"),
+												DatabaseID:   proto.DatabaseID("db1"),
+												ConnectionID: uint64(1),
+												SeqNo:        uint64(2),
+												Timestamp:    time.Now().UTC(),
+											},
+										},
+										NodeID:    proto.NodeID("0000000000000000000000000000000000000000000000000000000000003333"),
+										Timestamp: time.Now().UTC(),
+										RowCount:  uint64(1),
+									},
+								},
+							},
+						},
+					},
+					Peers: &proto.Peers{
+						PeersHeader: proto.PeersHeader{
+							Term:   uint64(1),
+							Leader: proto.NodeID("0000000000000000000000000000000000000000000000000000000000003333"),
+							Servers: []proto.NodeID{
+								proto.NodeID("0000000000000000000000000000000000000000000000000000000000003333"),
+								proto.NodeID("0000000000000000000000000000000000000000000000000000000000002222"),
+							},
+						},
+					},
+				},
+			},
+		}
+
+		var err error
+
+		// sign directly, embedded original response/request is not filled
+		err = aggrNoAck.Sign(privKey)
+		So(err, ShouldNotBeNil)
+		So(errors.Cause(err), ShouldBeIn, []error{
+			verifier.ErrHashValueNotMatch,
+			verifier.ErrSignatureNotMatch,
+		})
+
+		// sign nested structure
+		err = aggrNoAck.Header.Reports[0].Response.Request.Sign(privKey)
+		So(err, ShouldBeNil)
+		err = aggrNoAck.Header.Reports[1].Response.Request.Sign(privKey)
+		So(err, ShouldBeNil)
+		err = aggrNoAck.Header.Reports[0].Response.Sign(privKey)
+		So(err, ShouldBeNil)
+		err = aggrNoAck.Header.Reports[1].Response.Sign(privKey)
+		So(err, ShouldBeNil)
+		err = aggrNoAck.Header.Reports[0].Sign(privKey)
+		So(err, ShouldBeNil)
+		err = aggrNoAck.Header.Reports[1].Sign(privKey)
+		So(err, ShouldBeNil)
+		err = aggrNoAck.Sign(privKey)
+		So(err, ShouldBeNil)
+
+		Convey("verify", func() {
+			err = aggrNoAck.Verify()
+			So(err, ShouldBeNil)
+
+			Convey("request change", func() {
+				aggrNoAck.Header.Reports[0].Response.Request.QueryType = ReadQuery
+
+				err = aggrNoAck.Verify()
+				So(err, ShouldNotBeNil)
+			})
+
+			Convey("response change", func() {
+				aggrNoAck.Header.Reports[0].Response.RowCount = 1000
+
+				err = aggrNoAck.Verify()
+				So(err, ShouldNotBeNil)
+			})
+
+			Convey("report change", func() {
+				aggrNoAck.Header.Reports[0].Timestamp = aggrNoAck.Header.Reports[0].Timestamp.Add(time.Second)
+
+				err = aggrNoAck.Verify()
+				So(err, ShouldNotBeNil)
+			})
+
+			Convey("header change", func() {
+				aggrNoAck.Header.Timestamp = aggrNoAck.Header.Timestamp.Add(time.Second)
+
+				err = aggrNoAck.Verify()
+				So(err, ShouldNotBeNil)
+			})
+		})
+	})
+}
+
+func TestInitServiceResponse_Sign(t *testing.T) {
+	privKey, _ := getCommKeys()
+
+	Convey("sign", t, func() {
+		var err error
+
+		initServiceResponse := &InitServiceResponse{
+			Header: SignedInitServiceResponseHeader{
+				InitServiceResponseHeader: InitServiceResponseHeader{
+					Instances: []ServiceInstance{
+						{
+							DatabaseID: proto.DatabaseID("db1"),
+							Peers: &proto.Peers{
+								PeersHeader: proto.PeersHeader{
+									Term:   uint64(1),
+									Leader: proto.NodeID("0000000000000000000000000000000000000000000000000000000000003333"),
+									Servers: []proto.NodeID{
+										proto.NodeID("0000000000000000000000000000000000000000000000000000000000003333"),
+										proto.NodeID("0000000000000000000000000000000000000000000000000000000000002222"),
+									},
+								},
+							},
+							// TODO(xq262144), should integrated with genesis block serialization test
+							GenesisBlock: nil,
+						},
+					},
+				},
+			},
+		}
+
+		// sign
+		err = initServiceResponse.Sign(privKey)
+
+		Convey("verify", func() {
+			err = initServiceResponse.Verify()
+			So(err, ShouldBeNil)
+
+			Convey("header change", func() {
+				initServiceResponse.Header.Instances[0].DatabaseID = proto.DatabaseID("db2")
+
+				err = initServiceResponse.Verify()
+				So(err, ShouldNotBeNil)
+			})
+		})
+	})
+}
+
+func TestUpdateService_Sign(t *testing.T) {
+	privKey, _ := getCommKeys()
+
+	Convey("sign", t, func() {
+		var err error
+
+		updateServiceReq := &UpdateService{
+			Header: SignedUpdateServiceHeader{
+				UpdateServiceHeader: UpdateServiceHeader{
+					Op: CreateDB,
+					Instance: ServiceInstance{
+						DatabaseID: proto.DatabaseID("db1"),
+						Peers: &proto.Peers{
+							PeersHeader: proto.PeersHeader{
+								Term:   uint64(1),
+								Leader: proto.NodeID("0000000000000000000000000000000000000000000000000000000000003333"),
+								Servers: []proto.NodeID{
+									proto.NodeID("0000000000000000000000000000000000000000000000000000000000003333"),
+									proto.NodeID("0000000000000000000000000000000000000000000000000000000000002222"),
+								},
+							},
+						},
+						// TODO(xq262144), should integrated with genesis block serialization test
+						GenesisBlock: nil,
+					},
+				},
+			},
+		}
+
+		// sign
+		err = updateServiceReq.Sign(privKey)
+
+		Convey("verify", func() {
+			err = updateServiceReq.Verify()
+			So(err, ShouldBeNil)
+
+			Convey("header change", func() {
+				updateServiceReq.Header.Instance.DatabaseID = proto.DatabaseID("db2")
+
+				err = updateServiceReq.Verify()
+				So(err, ShouldNotBeNil)
+			})
+		})
+	})
+}
+
+func TestOther_MarshalHash(t *testing.T) {
+	Convey("marshal hash", t, func() {
+		tm := UpdateType(1)
+		s, err := tm.MarshalHash()
+		So(err, ShouldBeNil)
+		So(s, ShouldNotBeEmpty)
+
+		tm2 := QueryType(1)
+		s, err = tm2.MarshalHash()
+		So(err, ShouldBeNil)
+		So(s, ShouldNotBeEmpty)
+	})
+}
+
+func TestQueryTypeStringer(t *testing.T) {
+	Convey("Query type stringer should return expected string", t, func() {
+		var cases = [...]struct {
+			i fmt.Stringer
+			s string
+		}{
+			{
+				i: ReadQuery,
+				s: "read",
+			}, {
+				i: WriteQuery,
+				s: "write",
+			}, {
+				i: QueryType(0xffff),
+				s: "unknown",
+			},
+		}
+		for _, v := range cases {
+			So(v.s, ShouldEqual, fmt.Sprintf("%v", v.i))
+		}
+	})
+}
diff --git a/types/update_service_type.go b/types/update_service_type.go
new file mode 100644
index 000000000..7eca089bf
--- /dev/null
+++ b/types/update_service_type.go
@@ -0,0 +1,79 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+)
+
+//go:generate hsp
+
+// UpdateType defines service update type.
+type UpdateType int32
+
+const (
+	// CreateDB indicates create database operation.
+	CreateDB UpdateType = iota
+	// UpdateDB indicates database peers update operation.
+	UpdateDB
+	// DropDB indicates drop database operation.
+	DropDB
+)
+
+// UpdateServiceHeader defines service update header.
+type UpdateServiceHeader struct {
+	Op       UpdateType
+	Instance ServiceInstance
+}
+
+// SignedUpdateServiceHeader defines signed service update header.
+type SignedUpdateServiceHeader struct {
+	UpdateServiceHeader
+	verifier.DefaultHashSignVerifierImpl
+}
+
+// UpdateService defines service update type.
+type UpdateService struct {
+	proto.Envelope
+	Header SignedUpdateServiceHeader
+}
+
+// UpdateServiceResponse defines empty response entity.
+type UpdateServiceResponse struct{}
+
+// Verify checks hash and signature in update service header.
+func (sh *SignedUpdateServiceHeader) Verify() (err error) {
+	return sh.DefaultHashSignVerifierImpl.Verify(&sh.UpdateServiceHeader)
+}
+
+// Sign the request.
+func (sh *SignedUpdateServiceHeader) Sign(signer *asymmetric.PrivateKey) (err error) {
+	return sh.DefaultHashSignVerifierImpl.Sign(&sh.UpdateServiceHeader, signer)
+}
+
+// Verify checks hash and signature in update service.
+func (s *UpdateService) Verify() error {
+	return s.Header.Verify()
+}
+
+// Sign the request.
+func (s *UpdateService) Sign(signer *asymmetric.PrivateKey) (err error) {
+	// sign
+	return s.Header.Sign(signer)
+}
diff --git a/types/update_service_type_gen.go b/types/update_service_type_gen.go
new file mode 100644
index 000000000..c134c6635
--- /dev/null
+++ b/types/update_service_type_gen.go
@@ -0,0 +1,113 @@
+package types
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	hsp "github.com/CovenantSQL/HashStablePack/marshalhash"
+)
+
+// MarshalHash marshals for hash
+func (z *SignedUpdateServiceHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	// map header, size 2
+	o = append(o, 0x82, 0x82, 0x82, 0x82)
+	o = hsp.AppendInt32(o, int32(z.UpdateServiceHeader.Op))
+	o = append(o, 0x82)
+	if oTemp, err := z.UpdateServiceHeader.Instance.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *SignedUpdateServiceHeader) Msgsize() (s int) {
+	s = 1 + 20 + 1 + 3 + hsp.Int32Size + 9 + z.UpdateServiceHeader.Instance.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *UpdateService) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	if oTemp, err := z.Header.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.Envelope.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *UpdateService) Msgsize() (s int) {
+	s = 1 + 7 + z.Header.Msgsize() + 9 + z.Envelope.Msgsize()
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *UpdateServiceHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	if oTemp, err := z.Instance.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	o = hsp.AppendInt32(o, int32(z.Op))
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *UpdateServiceHeader) Msgsize() (s int) {
+	s = 1 + 9 + z.Instance.Msgsize() + 3 + hsp.Int32Size
+	return
+}
+
+// MarshalHash marshals for hash
+func (z UpdateServiceResponse) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 0
+	o = append(o, 0x80)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z UpdateServiceResponse) Msgsize() (s int) {
+	s = 1
+	return
+}
+
+// MarshalHash marshals for hash
+func (z UpdateType) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	o = hsp.AppendInt32(o, int32(z))
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z UpdateType) Msgsize() (s int) {
+	s = hsp.Int32Size
+	return
+}
diff --git a/worker/types/update_service_type_gen_test.go b/types/update_service_type_gen_test.go
similarity index 100%
rename from worker/types/update_service_type_gen_test.go
rename to types/update_service_type_gen_test.go
diff --git a/types/util.go b/types/util.go
new file mode 100644
index 000000000..ab09e4310
--- /dev/null
+++ b/types/util.go
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/pkg/errors"
+)
+
+type canMarshalHash interface {
+	MarshalHash() ([]byte, error)
+}
+
+func verifyHash(data canMarshalHash, h *hash.Hash) (err error) {
+	var newHash hash.Hash
+	if err = buildHash(data, &newHash); err != nil {
+		return
+	}
+	if !newHash.IsEqual(h) {
+		return errors.Cause(verifier.ErrHashValueNotMatch)
+	}
+	return
+}
+
+func buildHash(data canMarshalHash, h *hash.Hash) (err error) {
+	var hashBytes []byte
+	if hashBytes, err = data.MarshalHash(); err != nil {
+		return
+	}
+	newHash := hash.THashH(hashBytes)
+	copy(h[:], newHash[:])
+	return
+}
diff --git a/types/xxx_test.go b/types/xxx_test.go
new file mode 100644
index 000000000..55d87c586
--- /dev/null
+++ b/types/xxx_test.go
@@ -0,0 +1,136 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"io/ioutil"
+	"math/rand"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
+	"github.com/CovenantSQL/CovenantSQL/pow/cpuminer"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
+)
+
+var (
+	genesisHash = hash.Hash{}
+)
+
+func setup() {
+	rand.Seed(time.Now().UnixNano())
+	rand.Read(genesisHash[:])
+	f, err := ioutil.TempFile("", "keystore")
+
+	if err != nil {
+		panic(err)
+	}
+
+	f.Close()
+
+	if err = kms.InitPublicKeyStore(f.Name(), nil); err != nil {
+		panic(err)
+	}
+
+	kms.Unittest = true
+
+	if priv, pub, err := asymmetric.GenSecp256k1KeyPair(); err == nil {
+		kms.SetLocalKeyPair(priv, pub)
+	} else {
+		panic(err)
+	}
+
+	log.SetOutput(os.Stdout)
+	log.SetLevel(log.DebugLevel)
+}
+
+func createRandomString(offset, length int, s *string) {
+	buff := make([]byte, rand.Intn(length)+offset)
+	rand.Read(buff)
+	*s = string(buff)
+}
+
+func createRandomStrings(offset, length, soffset, slength int) (s []string) {
+	s = make([]string, rand.Intn(length)+offset)
+
+	for i := range s {
+		createRandomString(soffset, slength, &s[i])
+	}
+
+	return
+}
+
+func createRandomBlock(parent hash.Hash, isGenesis bool) (b *Block, err error) {
+	// Generate key pair
+	priv, pub, err := asymmetric.GenSecp256k1KeyPair()
+
+	if err != nil {
+		return
+	}
+
+	h := hash.Hash{}
+	rand.Read(h[:])
+
+	b = &Block{
+		SignedHeader: SignedHeader{
+			Header: Header{
+				Version:     0x01000000,
+				Producer:    proto.NodeID(h.String()),
+				GenesisHash: genesisHash,
+				ParentHash:  parent,
+				Timestamp:   time.Now().UTC(),
+			},
+		},
+	}
+
+	if isGenesis {
+		// Compute nonce with public key
+		nonceCh := make(chan cpuminer.NonceInfo)
+		quitCh := make(chan struct{})
+		miner := cpuminer.NewCPUMiner(quitCh)
+		go miner.ComputeBlockNonce(cpuminer.MiningBlock{
+			Data:      pub.Serialize(),
+			NonceChan: nonceCh,
+			Stop:      nil,
+		}, cpuminer.Uint256{A: 0, B: 0, C: 0, D: 0}, 4)
+		nonce := <-nonceCh
+		close(quitCh)
+		close(nonceCh)
+		// Add public key to KMS
+		id := cpuminer.HashBlock(pub.Serialize(), nonce.Nonce)
+		b.SignedHeader.Header.Producer = proto.NodeID(id.String())
+
+		if err = kms.SetPublicKey(proto.NodeID(id.String()), nonce.Nonce, pub); err != nil {
+			return nil, err
+		}
+
+		// Set genesis hash as zero value
+		b.SignedHeader.GenesisHash = hash.Hash{}
+	}
+
+	err = b.PackAndSignBlock(priv)
+	return
+}
+
+func TestMain(m *testing.M) {
+	setup()
+	os.Exit(m.Run())
+}
diff --git a/utils/profiler.go b/utils/profiler.go
index 013dd3e7c..01b5f9b67 100644
--- a/utils/profiler.go
+++ b/utils/profiler.go
@@ -48,7 +48,7 @@ func StartProfile(cpuprofile, memprofile string) error {
 			log.WithField("file", memprofile).WithError(err).Error("failed to create memory profile file")
 			return err
 		}
-		log.WithField("file", cpuprofile).WithError(err).Info("writing memory profiling to file")
+		log.WithField("file", memprofile).WithError(err).Info("writing memory profiling to file")
 		prof.mem = f
 		runtime.MemProfileRate = 4096
 	}
@@ -63,7 +63,7 @@ func StopProfile() {
 		log.Info("CPU profiling stopped")
 	}
 	if prof.mem != nil {
-		pprof.Lookup("heap").WriteTo(prof.mem, 0)
+		pprof.WriteHeapProfile(prof.mem)
 		prof.mem.Close()
 		log.Info("memory profiling stopped")
 	}
diff --git a/vendor/bazil.org/fuse/.gitattributes b/vendor/bazil.org/fuse/.gitattributes
new file mode 100644
index 000000000..b65f2a9ff
--- /dev/null
+++ b/vendor/bazil.org/fuse/.gitattributes
@@ -0,0 +1,2 @@
+*.go filter=gofmt
+*.cgo filter=gofmt
diff --git a/vendor/bazil.org/fuse/LICENSE b/vendor/bazil.org/fuse/LICENSE
new file mode 100644
index 000000000..4ac7cd838
--- /dev/null
+++ b/vendor/bazil.org/fuse/LICENSE
@@ -0,0 +1,93 @@
+Copyright (c) 2013-2015 Tommi Virtanen.
+Copyright (c) 2009, 2011, 2012 The Go Authors.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+
+The following included software components have additional copyright
+notices and license terms that may differ from the above.
+
+
+File fuse.go:
+
+// Adapted from Plan 9 from User Space's src/cmd/9pfuse/fuse.c,
+// which carries this notice:
+//
+// The files in this directory are subject to the following license.
+//
+// The author of this software is Russ Cox.
+//
+//         Copyright (c) 2006 Russ Cox
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose without fee is hereby granted, provided that this entire notice
+// is included in all copies of any software which is or includes a copy
+// or modification of this software and in all copies of the supporting
+// documentation for such software.
+//
+// THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
+// WARRANTY.  IN PARTICULAR, THE AUTHOR MAKES NO REPRESENTATION OR WARRANTY
+// OF ANY KIND CONCERNING THE MERCHANTABILITY OF THIS SOFTWARE OR ITS
+// FITNESS FOR ANY PARTICULAR PURPOSE.
+
+
+File fuse_kernel.go:
+
+// Derived from FUSE's fuse_kernel.h
+/*
+   This file defines the kernel interface of FUSE
+   Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
+
+
+   This -- and only this -- header file may also be distributed under
+   the terms of the BSD Licence as follows:
+
+   Copyright (C) 2001-2007 Miklos Szeredi. All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+   1. Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+   2. Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+   THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+   ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+   ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+   OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+   SUCH DAMAGE.
+*/
diff --git a/vendor/bazil.org/fuse/README.md b/vendor/bazil.org/fuse/README.md
new file mode 100644
index 000000000..8c6d556ee
--- /dev/null
+++ b/vendor/bazil.org/fuse/README.md
@@ -0,0 +1,23 @@
+bazil.org/fuse -- Filesystems in Go
+===================================
+
+`bazil.org/fuse` is a Go library for writing FUSE userspace
+filesystems.
+
+It is a from-scratch implementation of the kernel-userspace
+communication protocol, and does not use the C library from the
+project called FUSE. `bazil.org/fuse` embraces Go fully for safety and
+ease of programming.
+
+Here’s how to get going:
+
+    go get bazil.org/fuse
+
+Website: http://bazil.org/fuse/
+
+Github repository: https://github.com/bazil/fuse
+
+API docs: http://godoc.org/bazil.org/fuse
+
+Our thanks to Russ Cox for his fuse library, which this project is
+based on.
diff --git a/vendor/bazil.org/fuse/buffer.go b/vendor/bazil.org/fuse/buffer.go
new file mode 100644
index 000000000..bb1d2b776
--- /dev/null
+++ b/vendor/bazil.org/fuse/buffer.go
@@ -0,0 +1,35 @@
+package fuse
+
+import "unsafe"
+
+// buffer provides a mechanism for constructing a message from
+// multiple segments.
+type buffer []byte
+
+// alloc allocates size bytes and returns a pointer to the new
+// segment.
+func (w *buffer) alloc(size uintptr) unsafe.Pointer {
+	s := int(size)
+	if len(*w)+s > cap(*w) {
+		old := *w
+		*w = make([]byte, len(*w), 2*cap(*w)+s)
+		copy(*w, old)
+	}
+	l := len(*w)
+	*w = (*w)[:l+s]
+	return unsafe.Pointer(&(*w)[l])
+}
+
+// reset clears out the contents of the buffer.
+func (w *buffer) reset() {
+	for i := range (*w)[:cap(*w)] {
+		(*w)[i] = 0
+	}
+	*w = (*w)[:0]
+}
+
+func newBuffer(extra uintptr) buffer {
+	const hdrSize = unsafe.Sizeof(outHeader{})
+	buf := make(buffer, hdrSize, hdrSize+extra)
+	return buf
+}
diff --git a/vendor/bazil.org/fuse/debug.go b/vendor/bazil.org/fuse/debug.go
new file mode 100644
index 000000000..be9f900d5
--- /dev/null
+++ b/vendor/bazil.org/fuse/debug.go
@@ -0,0 +1,21 @@
+package fuse
+
+import (
+	"runtime"
+)
+
+func stack() string {
+	buf := make([]byte, 1024)
+	return string(buf[:runtime.Stack(buf, false)])
+}
+
+func nop(msg interface{}) {}
+
+// Debug is called to output debug messages, including protocol
+// traces. The default behavior is to do nothing.
+//
+// The messages have human-friendly string representations and are
+// safe to marshal to JSON.
+//
+// Implementations must not retain msg.
+var Debug func(msg interface{}) = nop
diff --git a/vendor/bazil.org/fuse/error_darwin.go b/vendor/bazil.org/fuse/error_darwin.go
new file mode 100644
index 000000000..a3fb89ca2
--- /dev/null
+++ b/vendor/bazil.org/fuse/error_darwin.go
@@ -0,0 +1,17 @@
+package fuse
+
+import (
+	"syscall"
+)
+
+const (
+	ENOATTR = Errno(syscall.ENOATTR)
+)
+
+const (
+	errNoXattr = ENOATTR
+)
+
+func init() {
+	errnoNames[errNoXattr] = "ENOATTR"
+}
diff --git a/vendor/bazil.org/fuse/error_freebsd.go b/vendor/bazil.org/fuse/error_freebsd.go
new file mode 100644
index 000000000..c6ea6d6e7
--- /dev/null
+++ b/vendor/bazil.org/fuse/error_freebsd.go
@@ -0,0 +1,15 @@
+package fuse
+
+import "syscall"
+
+const (
+	ENOATTR = Errno(syscall.ENOATTR)
+)
+
+const (
+	errNoXattr = ENOATTR
+)
+
+func init() {
+	errnoNames[errNoXattr] = "ENOATTR"
+}
diff --git a/vendor/bazil.org/fuse/error_linux.go b/vendor/bazil.org/fuse/error_linux.go
new file mode 100644
index 000000000..6f113e71e
--- /dev/null
+++ b/vendor/bazil.org/fuse/error_linux.go
@@ -0,0 +1,17 @@
+package fuse
+
+import (
+	"syscall"
+)
+
+const (
+	ENODATA = Errno(syscall.ENODATA)
+)
+
+const (
+	errNoXattr = ENODATA
+)
+
+func init() {
+	errnoNames[errNoXattr] = "ENODATA"
+}
diff --git a/vendor/bazil.org/fuse/error_std.go b/vendor/bazil.org/fuse/error_std.go
new file mode 100644
index 000000000..398f43fbf
--- /dev/null
+++ b/vendor/bazil.org/fuse/error_std.go
@@ -0,0 +1,31 @@
+package fuse
+
+// There is very little commonality in extended attribute errors
+// across platforms.
+//
+// getxattr return value for "extended attribute does not exist" is
+// ENOATTR on OS X, and ENODATA on Linux and apparently at least
+// NetBSD. There may be a #define ENOATTR on Linux too, but the value
+// is ENODATA in the actual syscalls. FreeBSD and OpenBSD have no
+// ENODATA, only ENOATTR. ENOATTR is not in any of the standards,
+// ENODATA exists but is only used for STREAMs.
+//
+// Each platform will define it a errNoXattr constant, and this file
+// will enforce that it implements the right interfaces and hide the
+// implementation.
+//
+// https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man2/getxattr.2.html
+// http://mail-index.netbsd.org/tech-kern/2012/04/30/msg013090.html
+// http://mail-index.netbsd.org/tech-kern/2012/04/30/msg013097.html
+// http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html
+// http://www.freebsd.org/cgi/man.cgi?query=extattr_get_file&sektion=2
+// http://nixdoc.net/man-pages/openbsd/man2/extattr_get_file.2.html
+
+// ErrNoXattr is a platform-independent error value meaning the
+// extended attribute was not found. It can be used to respond to
+// GetxattrRequest and such.
+const ErrNoXattr = errNoXattr
+
+var _ error = ErrNoXattr
+var _ Errno = ErrNoXattr
+var _ ErrorNumber = ErrNoXattr
diff --git a/vendor/bazil.org/fuse/fs/fstestutil/checkdir.go b/vendor/bazil.org/fuse/fs/fstestutil/checkdir.go
new file mode 100644
index 000000000..74e5899e9
--- /dev/null
+++ b/vendor/bazil.org/fuse/fs/fstestutil/checkdir.go
@@ -0,0 +1,70 @@
+package fstestutil
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+)
+
+// FileInfoCheck is a function that validates an os.FileInfo according
+// to some criteria.
+type FileInfoCheck func(fi os.FileInfo) error
+
+type checkDirError struct {
+	missing map[string]struct{}
+	extra   map[string]os.FileMode
+}
+
+func (e *checkDirError) Error() string {
+	return fmt.Sprintf("wrong directory contents: missing %v, extra %v", e.missing, e.extra)
+}
+
+// CheckDir checks the contents of the directory at path, making sure
+// every directory entry listed in want is present. If the check is
+// not nil, it must also pass.
+//
+// If want contains the impossible filename "", unexpected files are
+// checked with that. If the key is not in want, unexpected files are
+// an error.
+//
+// Missing entries, that are listed in want but not seen, are an
+// error.
+func CheckDir(path string, want map[string]FileInfoCheck) error {
+	problems := &checkDirError{
+		missing: make(map[string]struct{}, len(want)),
+		extra:   make(map[string]os.FileMode),
+	}
+	for k := range want {
+		if k == "" {
+			continue
+		}
+		problems.missing[k] = struct{}{}
+	}
+
+	fis, err := ioutil.ReadDir(path)
+	if err != nil {
+		return fmt.Errorf("cannot read directory: %v", err)
+	}
+
+	for _, fi := range fis {
+		check, ok := want[fi.Name()]
+		if !ok {
+			check, ok = want[""]
+		}
+		if !ok {
+			problems.extra[fi.Name()] = fi.Mode()
+			continue
+		}
+		delete(problems.missing, fi.Name())
+		if check != nil {
+			if err := check(fi); err != nil {
+				return fmt.Errorf("check failed: %v: %v", fi.Name(), err)
+			}
+		}
+	}
+
+	if len(problems.missing) > 0 || len(problems.extra) > 0 {
+		return problems
+	}
+	return nil
+}
diff --git a/vendor/bazil.org/fuse/fs/fstestutil/debug.go b/vendor/bazil.org/fuse/fs/fstestutil/debug.go
new file mode 100644
index 000000000..df44a0c65
--- /dev/null
+++ b/vendor/bazil.org/fuse/fs/fstestutil/debug.go
@@ -0,0 +1,65 @@
+package fstestutil
+
+import (
+	"flag"
+	"log"
+	"strconv"
+
+	"bazil.org/fuse"
+)
+
+type flagDebug bool
+
+var debug flagDebug
+
+var _ = flag.Value(&debug)
+
+func (f *flagDebug) IsBoolFlag() bool {
+	return true
+}
+
+func nop(msg interface{}) {}
+
+func (f *flagDebug) Set(s string) error {
+	v, err := strconv.ParseBool(s)
+	if err != nil {
+		return err
+	}
+	*f = flagDebug(v)
+	if v {
+		fuse.Debug = logMsg
+	} else {
+		fuse.Debug = nop
+	}
+	return nil
+}
+
+func (f *flagDebug) String() string {
+	return strconv.FormatBool(bool(*f))
+}
+
+func logMsg(msg interface{}) {
+	log.Printf("FUSE: %s\n", msg)
+}
+
+func init() {
+	flag.Var(&debug, "fuse.debug", "log FUSE processing details")
+}
+
+// DebugByDefault changes the default of the `-fuse.debug` flag to
+// true.
+//
+// This package registers a command line flag `-fuse.debug` and when
+// run with that flag (and activated inside the tests), logs FUSE
+// debug messages.
+//
+// This is disabled by default, as most callers probably won't care
+// about FUSE details. Use DebugByDefault for tests where you'd
+// normally be passing `-fuse.debug` all the time anyway.
+//
+// Call from an init function.
+func DebugByDefault() {
+	f := flag.Lookup("fuse.debug")
+	f.DefValue = "true"
+	f.Value.Set(f.DefValue)
+}
diff --git a/vendor/bazil.org/fuse/fs/fstestutil/doc.go b/vendor/bazil.org/fuse/fs/fstestutil/doc.go
new file mode 100644
index 000000000..3f729dddc
--- /dev/null
+++ b/vendor/bazil.org/fuse/fs/fstestutil/doc.go
@@ -0,0 +1 @@
+package fstestutil // import "bazil.org/fuse/fs/fstestutil"
diff --git a/vendor/bazil.org/fuse/fs/fstestutil/mounted.go b/vendor/bazil.org/fuse/fs/fstestutil/mounted.go
new file mode 100644
index 000000000..2fae1588a
--- /dev/null
+++ b/vendor/bazil.org/fuse/fs/fstestutil/mounted.go
@@ -0,0 +1,141 @@
+package fstestutil
+
+import (
+	"errors"
+	"io/ioutil"
+	"log"
+	"os"
+	"testing"
+	"time"
+
+	"bazil.org/fuse"
+	"bazil.org/fuse/fs"
+)
+
+// Mount contains information about the mount for the test to use.
+type Mount struct {
+	// Dir is the temporary directory where the filesystem is mounted.
+	Dir string
+
+	Conn   *fuse.Conn
+	Server *fs.Server
+
+	// Error will receive the return value of Serve.
+	Error <-chan error
+
+	done   <-chan struct{}
+	closed bool
+}
+
+// Close unmounts the filesystem and waits for fs.Serve to return. Any
+// returned error will be stored in Err. It is safe to call Close
+// multiple times.
+func (mnt *Mount) Close() {
+	if mnt.closed {
+		return
+	}
+	mnt.closed = true
+	for tries := 0; tries < 1000; tries++ {
+		err := fuse.Unmount(mnt.Dir)
+		if err != nil {
+			// TODO do more than log?
+			log.Printf("unmount error: %v", err)
+			time.Sleep(10 * time.Millisecond)
+			continue
+		}
+		break
+	}
+	<-mnt.done
+	mnt.Conn.Close()
+	os.Remove(mnt.Dir)
+}
+
+// MountedFunc mounts a filesystem at a temporary directory. The
+// filesystem used is constructed by calling a function, to allow
+// storing fuse.Conn and fs.Server in the FS.
+//
+// It also waits until the filesystem is known to be visible (OS X
+// workaround).
+//
+// After successful return, caller must clean up by calling Close.
+func MountedFunc(fn func(*Mount) fs.FS, conf *fs.Config, options ...fuse.MountOption) (*Mount, error) {
+	dir, err := ioutil.TempDir("", "fusetest")
+	if err != nil {
+		return nil, err
+	}
+	c, err := fuse.Mount(dir, options...)
+	if err != nil {
+		return nil, err
+	}
+	server := fs.New(c, conf)
+	done := make(chan struct{})
+	serveErr := make(chan error, 1)
+	mnt := &Mount{
+		Dir:    dir,
+		Conn:   c,
+		Server: server,
+		Error:  serveErr,
+		done:   done,
+	}
+	filesys := fn(mnt)
+	go func() {
+		defer close(done)
+		serveErr <- server.Serve(filesys)
+	}()
+
+	select {
+	case <-mnt.Conn.Ready:
+		if err := mnt.Conn.MountError; err != nil {
+			return nil, err
+		}
+		return mnt, nil
+	case err = <-mnt.Error:
+		// Serve quit early
+		if err != nil {
+			return nil, err
+		}
+		return nil, errors.New("Serve exited early")
+	}
+}
+
+// Mounted mounts the fuse.Server at a temporary directory.
+//
+// It also waits until the filesystem is known to be visible (OS X
+// workaround).
+//
+// After successful return, caller must clean up by calling Close.
+func Mounted(filesys fs.FS, conf *fs.Config, options ...fuse.MountOption) (*Mount, error) {
+	fn := func(*Mount) fs.FS { return filesys }
+	return MountedFunc(fn, conf, options...)
+}
+
+// MountedFuncT mounts a filesystem at a temporary directory,
+// directing it's debug log to the testing logger.
+//
+// See MountedFunc for usage.
+//
+// The debug log is not enabled by default. Use `-fuse.debug` or call
+// DebugByDefault to enable.
+func MountedFuncT(t testing.TB, fn func(*Mount) fs.FS, conf *fs.Config, options ...fuse.MountOption) (*Mount, error) {
+	if conf == nil {
+		conf = &fs.Config{}
+	}
+	if debug && conf.Debug == nil {
+		conf.Debug = func(msg interface{}) {
+			t.Logf("FUSE: %s", msg)
+		}
+	}
+	return MountedFunc(fn, conf, options...)
+}
+
+// MountedT mounts the filesystem at a temporary directory,
+// directing it's debug log to the testing logger.
+//
+// See Mounted for usage.
+//
+// The debug log is not enabled by default. Use `-fuse.debug` or call
+// DebugByDefault to enable.
+func MountedT(t testing.TB, filesys fs.FS, conf *fs.Config, options ...fuse.MountOption) (*Mount, error) {
+	fn := func(*Mount) fs.FS { return filesys }
+	return MountedFuncT(t, fn, conf, options...)
+}
diff --git a/vendor/bazil.org/fuse/fs/fstestutil/mountinfo.go b/vendor/bazil.org/fuse/fs/fstestutil/mountinfo.go
new file mode 100644
index 000000000..654417bc4
--- /dev/null
+++ b/vendor/bazil.org/fuse/fs/fstestutil/mountinfo.go
@@ -0,0 +1,26 @@
+package fstestutil
+
+// MountInfo describes a mounted file system.
+type MountInfo struct {
+	FSName string
+	Type   string
+}
+
+// GetMountInfo finds information about the mount at mnt. It is
+// intended for use by tests only, and only fetches information
+// relevant to the current tests.
+func GetMountInfo(mnt string) (*MountInfo, error) {
+	return getMountInfo(mnt)
+}
+
+// cstr converts a nil-terminated C string into a Go string
+func cstr(ca []int8) string {
+	s := make([]byte, 0, len(ca))
+	for _, c := range ca {
+		if c == 0x00 {
+			break
+		}
+		s = append(s, byte(c))
+	}
+	return string(s)
+}
diff --git a/vendor/bazil.org/fuse/fs/fstestutil/mountinfo_darwin.go b/vendor/bazil.org/fuse/fs/fstestutil/mountinfo_darwin.go
new file mode 100644
index 000000000..f987bd8e7
--- /dev/null
+++ b/vendor/bazil.org/fuse/fs/fstestutil/mountinfo_darwin.go
@@ -0,0 +1,29 @@
+package fstestutil
+
+import (
+	"regexp"
+	"syscall"
+)
+
+var re = regexp.MustCompile(`\\(.)`)
+
+// unescape removes backslash-escaping. The escaped characters are not
+// mapped in any way; that is, unescape(`\n` ) == `n`.
+func unescape(s string) string {
+	return re.ReplaceAllString(s, `$1`)
+}
+
+func getMountInfo(mnt string) (*MountInfo, error) {
+	var st syscall.Statfs_t
+	err := syscall.Statfs(mnt, &st)
+	if err != nil {
+		return nil, err
+	}
+	i := &MountInfo{
+		// osx getmntent(3) fails to un-escape the data, so we do it..
+		// this might lead to double-unescaping in the future. fun.
+		// TestMountOptionFSNameEvilBackslashDouble checks for that.
+		FSName: unescape(cstr(st.Mntfromname[:])),
+	}
+	return i, nil
+}
diff --git a/vendor/bazil.org/fuse/fs/fstestutil/mountinfo_freebsd.go b/vendor/bazil.org/fuse/fs/fstestutil/mountinfo_freebsd.go
new file mode 100644
index 000000000..f70e9975e
--- /dev/null
+++ b/vendor/bazil.org/fuse/fs/fstestutil/mountinfo_freebsd.go
@@ -0,0 +1,7 @@
+package fstestutil
+
+import "errors"
+
+func getMountInfo(mnt string) (*MountInfo, error) {
+	return nil, errors.New("FreeBSD has no useful mount information")
+}
diff --git a/vendor/bazil.org/fuse/fs/fstestutil/mountinfo_linux.go b/vendor/bazil.org/fuse/fs/fstestutil/mountinfo_linux.go
new file mode 100644
index 000000000..c502cf59b
--- /dev/null
+++ b/vendor/bazil.org/fuse/fs/fstestutil/mountinfo_linux.go
@@ -0,0 +1,51 @@
+package fstestutil
+
+import (
+	"errors"
+	"io/ioutil"
+	"strings"
+)
+
+// Linux /proc/mounts shows current mounts.
+// Same format as /etc/fstab. Quoting getmntent(3):
+//
+// Since fields in the mtab and fstab files are separated by whitespace,
+// octal escapes are used to represent the four characters space (\040),
+// tab (\011), newline (\012) and backslash (\134) in those files when
+// they occur in one of the four strings in a mntent structure.
+//
+// http://linux.die.net/man/3/getmntent
+
+var fstabUnescape = strings.NewReplacer(
+	`\040`, "\040",
+	`\011`, "\011",
+	`\012`, "\012",
+	`\134`, "\134",
+)
+
+var errNotFound = errors.New("mount not found")
+
+func getMountInfo(mnt string) (*MountInfo, error) {
+	data, err := ioutil.ReadFile("/proc/mounts")
+	if err != nil {
+		return nil, err
+	}
+	for _, line := range strings.Split(string(data), "\n") {
+		fields := strings.Fields(line)
+		if len(fields) < 3 {
+			continue
+		}
+		// Fields are: fsname dir type opts freq passno
+		fsname := fstabUnescape.Replace(fields[0])
+		dir := fstabUnescape.Replace(fields[1])
+		fstype := fstabUnescape.Replace(fields[2])
+		if mnt == dir {
+			info := &MountInfo{
+				FSName: fsname,
+				Type:   fstype,
+			}
+			return info, nil
+		}
+	}
+	return nil, errNotFound
+}
diff --git a/vendor/bazil.org/fuse/fs/fstestutil/testfs.go b/vendor/bazil.org/fuse/fs/fstestutil/testfs.go
new file mode 100644
index 000000000..c1988bf70
--- /dev/null
+++ b/vendor/bazil.org/fuse/fs/fstestutil/testfs.go
@@ -0,0 +1,55 @@
+package fstestutil
+
+import (
+	"os"
+
+	"bazil.org/fuse"
+	"bazil.org/fuse/fs"
+	"golang.org/x/net/context"
+)
+
+// SimpleFS is a trivial FS that just implements the Root method.
+type SimpleFS struct {
+	Node fs.Node
+}
+
+var _ = fs.FS(SimpleFS{})
+
+func (f SimpleFS) Root() (fs.Node, error) {
+	return f.Node, nil
+}
+
+// File can be embedded in a struct to make it look like a file.
+type File struct{}
+
+func (f File) Attr(ctx context.Context, a *fuse.Attr) error {
+	a.Mode = 0666
+	return nil
+}
+
+// Dir can be embedded in a struct to make it look like a directory.
+type Dir struct{}
+
+func (f Dir) Attr(ctx context.Context, a *fuse.Attr) error {
+	a.Mode = os.ModeDir | 0777
+	return nil
+}
+
+// ChildMap is a directory with child nodes looked up from a map.
+type ChildMap map[string]fs.Node
+
+var _ = fs.Node(&ChildMap{})
+var _ = fs.NodeStringLookuper(&ChildMap{})
+
+func (f *ChildMap) Attr(ctx context.Context, a *fuse.Attr) error {
+	a.Mode = os.ModeDir | 0777
+	return nil
+}
+
+func (f *ChildMap) Lookup(ctx context.Context, name string) (fs.Node, error) {
+	child, ok := (*f)[name]
+	if !ok {
+		return nil, fuse.ENOENT
+	}
+	return child, nil
+}
diff --git a/vendor/bazil.org/fuse/fs/serve.go b/vendor/bazil.org/fuse/fs/serve.go
new file mode 100644
index 000000000..e9fc56590
--- /dev/null
+++ b/vendor/bazil.org/fuse/fs/serve.go
@@ -0,0 +1,1568 @@
+// FUSE service loop, for servers that wish to use it.
+
+package fs // import "bazil.org/fuse/fs"
+
+import (
+	"encoding/binary"
+	"fmt"
+	"hash/fnv"
+	"io"
+	"log"
+	"reflect"
+	"runtime"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/net/context"
+)
+
+import (
+	"bytes"
+
+	"bazil.org/fuse"
+	"bazil.org/fuse/fuseutil"
+)
+
+const (
+	attrValidTime  = 1 * time.Minute
+	entryValidTime = 1 * time.Minute
+)
+
+// TODO: FINISH DOCS
+
+// An FS is the interface required of a file system.
+//
+// Other FUSE requests can be handled by implementing methods from the
+// FS* interfaces, for example FSStatfser.
+type FS interface {
+	// Root is called to obtain the Node for the file system root.
+	Root() (Node, error)
+}
+
+type FSStatfser interface {
+	// Statfs is called to obtain file system metadata.
+	// It should write that data to resp.
+	Statfs(ctx context.Context, req *fuse.StatfsRequest, resp *fuse.StatfsResponse) error
+}
+
+type FSDestroyer interface {
+	// Destroy is called when the file system is shutting down.
+	//
+	// Linux only sends this request for block device backed (fuseblk)
+	// filesystems, to allow them to flush writes to disk before the
+	// unmount completes.
+	Destroy()
+}
+
+type FSInodeGenerator interface {
+	// GenerateInode is called to pick a dynamic inode number when it
+	// would otherwise be 0.
+	//
+	// Not all filesystems bother tracking inodes, but FUSE requires
+	// the inode to be set, and fewer duplicates in general makes UNIX
+	// tools work better.
+	//
+	// Operations where the nodes may return 0 inodes include Getattr,
+	// Setattr and ReadDir.
+	//
+	// If FS does not implement FSInodeGenerator, GenerateDynamicInode
+	// is used.
+	//
+	// Implementing this is useful to e.g. constrain the range of
+	// inode values used for dynamic inodes.
+	GenerateInode(parentInode uint64, name string) uint64
+}
+
+// A Node is the interface required of a file or directory.
+// See the documentation for type FS for general information
+// pertaining to all methods.
+//
+// A Node must be usable as a map key, that is, it cannot be a
+// function, map or slice.
+//
+// Other FUSE requests can be handled by implementing methods from the
+// Node* interfaces, for example NodeOpener.
+//
+// Methods returning Node should take care to return the same Node
+// when the result is logically the same instance. Without this, each
+// Node will get a new NodeID, causing spurious cache invalidations,
+// extra lookups and aliasing anomalies. This may not matter for a
+// simple, read-only filesystem.
+type Node interface {
+	// Attr fills attr with the standard metadata for the node.
+	//
+	// Fields with reasonable defaults are prepopulated. For example,
+	// all times are set to a fixed moment when the program started.
+	//
+	// If Inode is left as 0, a dynamic inode number is chosen.
+	//
+	// The result may be cached for the duration set in Valid.
+	Attr(ctx context.Context, attr *fuse.Attr) error
+}
+
+type NodeGetattrer interface {
+	// Getattr obtains the standard metadata for the receiver.
+	// It should store that metadata in resp.
+	//
+	// If this method is not implemented, the attributes will be
+	// generated based on Attr(), with zero values filled in.
+	Getattr(ctx context.Context, req *fuse.GetattrRequest, resp *fuse.GetattrResponse) error
+}
+
+type NodeSetattrer interface {
+	// Setattr sets the standard metadata for the receiver.
+	//
+	// Note, this is also used to communicate changes in the size of
+	// the file, outside of Writes.
+	//
+	// req.Valid is a bitmask of what fields are actually being set.
+	// For example, the method should not change the mode of the file
+	// unless req.Valid.Mode() is true.
+	Setattr(ctx context.Context, req *fuse.SetattrRequest, resp *fuse.SetattrResponse) error
+}
+
+type NodeSymlinker interface {
+	// Symlink creates a new symbolic link in the receiver, which must be a directory.
+	//
+	// TODO is the above true about directories?
+	Symlink(ctx context.Context, req *fuse.SymlinkRequest) (Node, error)
+}
+
+// This optional request will be called only for symbolic link nodes.
+type NodeReadlinker interface {
+	// Readlink reads a symbolic link.
+	Readlink(ctx context.Context, req *fuse.ReadlinkRequest) (string, error)
+}
+
+type NodeLinker interface {
+	// Link creates a new directory entry in the receiver based on an
+	// existing Node. Receiver must be a directory.
+	Link(ctx context.Context, req *fuse.LinkRequest, old Node) (Node, error)
+}
+
+type NodeRemover interface {
+	// Remove removes the entry with the given name from
+	// the receiver, which must be a directory.  The entry to be removed
+	// may correspond to a file (unlink) or to a directory (rmdir).
+	Remove(ctx context.Context, req *fuse.RemoveRequest) error
+}
+
+type NodeAccesser interface {
+	// Access checks whether the calling context has permission for
+	// the given operations on the receiver. If so, Access should
+	// return nil. If not, Access should return EPERM.
+	//
+	// Note that this call affects the result of the access(2) system
+	// call but not the open(2) system call. If Access is not
+	// implemented, the Node behaves as if it always returns nil
+	// (permission granted), relying on checks in Open instead.
+	Access(ctx context.Context, req *fuse.AccessRequest) error
+}
+
+type NodeStringLookuper interface {
+	// Lookup looks up a specific entry in the receiver,
+	// which must be a directory.  Lookup should return a Node
+	// corresponding to the entry.  If the name does not exist in
+	// the directory, Lookup should return ENOENT.
+	//
+	// Lookup need not to handle the names "." and "..".
+	Lookup(ctx context.Context, name string) (Node, error)
+}
+
+type NodeRequestLookuper interface {
+	// Lookup looks up a specific entry in the receiver.
+	// See NodeStringLookuper for more.
+	Lookup(ctx context.Context, req *fuse.LookupRequest, resp *fuse.LookupResponse) (Node, error)
+}
+
+type NodeMkdirer interface {
+	Mkdir(ctx context.Context, req *fuse.MkdirRequest) (Node, error)
+}
+
+type NodeOpener interface {
+	// Open opens the receiver. After a successful open, a client
+	// process has a file descriptor referring to this Handle.
+	//
+	// Open can also be also called on non-files. For example,
+	// directories are Opened for ReadDir or fchdir(2).
+	//
+	// If this method is not implemented, the open will always
+	// succeed, and the Node itself will be used as the Handle.
+	//
+	// XXX note about access.  XXX OpenFlags.
+	Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.OpenResponse) (Handle, error)
+}
+
+type NodeCreater interface {
+	// Create creates a new directory entry in the receiver, which
+	// must be a directory.
+	Create(ctx context.Context, req *fuse.CreateRequest, resp *fuse.CreateResponse) (Node, Handle, error)
+}
+
+type NodeForgetter interface {
+	// Forget about this node. This node will not receive further
+	// method calls.
+	//
+	// Forget is not necessarily seen on unmount, as all nodes are
+	// implicitly forgotten as part part of the unmount.
+	Forget()
+}
+
+type NodeRenamer interface {
+	Rename(ctx context.Context, req *fuse.RenameRequest, newDir Node) error
+}
+
+type NodeMknoder interface {
+	Mknod(ctx context.Context, req *fuse.MknodRequest) (Node, error)
+}
+
+// TODO this should be on Handle not Node
+type NodeFsyncer interface {
+	Fsync(ctx context.Context, req *fuse.FsyncRequest) error
+}
+
+type NodeGetxattrer interface {
+	// Getxattr gets an extended attribute by the given name from the
+	// node.
+	//
+	// If there is no xattr by that name, returns fuse.ErrNoXattr.
+	Getxattr(ctx context.Context, req *fuse.GetxattrRequest, resp *fuse.GetxattrResponse) error
+}
+
+type NodeListxattrer interface {
+	// Listxattr lists the extended attributes recorded for the node.
+	Listxattr(ctx context.Context, req *fuse.ListxattrRequest, resp *fuse.ListxattrResponse) error
+}
+
+type NodeSetxattrer interface {
+	// Setxattr sets an extended attribute with the given name and
+	// value for the node.
+	Setxattr(ctx context.Context, req *fuse.SetxattrRequest) error
+}
+
+type NodeRemovexattrer interface {
+	// Removexattr removes an extended attribute for the name.
+	//
+	// If there is no xattr by that name, returns fuse.ErrNoXattr.
+	Removexattr(ctx context.Context, req *fuse.RemovexattrRequest) error
+}
+
+var startTime = time.Now()
+
+func nodeAttr(ctx context.Context, n Node, attr *fuse.Attr) error {
+	attr.Valid = attrValidTime
+	attr.Nlink = 1
+	attr.Atime = startTime
+	attr.Mtime = startTime
+	attr.Ctime = startTime
+	attr.Crtime = startTime
+	if err := n.Attr(ctx, attr); err != nil {
+		return err
+	}
+	return nil
+}
+
+// A Handle is the interface required of an opened file or directory.
+// See the documentation for type FS for general information
+// pertaining to all methods.
+//
+// Other FUSE requests can be handled by implementing methods from the
+// Handle* interfaces. The most common to implement are HandleReader,
+// HandleReadDirer, and HandleWriter.
+//
+// TODO implement methods: Getlk, Setlk, Setlkw
+type Handle interface {
+}
+
+type HandleFlusher interface {
+	// Flush is called each time the file or directory is closed.
+	// Because there can be multiple file descriptors referring to a
+	// single opened file, Flush can be called multiple times.
+	Flush(ctx context.Context, req *fuse.FlushRequest) error
+}
+
+type HandleReadAller interface {
+	ReadAll(ctx context.Context) ([]byte, error)
+}
+
+type HandleReadDirAller interface {
+	ReadDirAll(ctx context.Context) ([]fuse.Dirent, error)
+}
+
+type HandleReader interface {
+	// Read requests to read data from the handle.
+	//
+	// There is a page cache in the kernel that normally submits only
+	// page-aligned reads spanning one or more pages. However, you
+	// should not rely on this. To see individual requests as
+	// submitted by the file system clients, set OpenDirectIO.
+	//
+	// Note that reads beyond the size of the file as reported by Attr
+	// are not even attempted (except in OpenDirectIO mode).
+	Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error
+}
+
+type HandleWriter interface {
+	// Write requests to write data into the handle at the given offset.
+	// Store the amount of data written in resp.Size.
+	//
+	// There is a writeback page cache in the kernel that normally submits
+	// only page-aligned writes spanning one or more pages. However,
+	// you should not rely on this. To see individual requests as
+	// submitted by the file system clients, set OpenDirectIO.
+	//
+	// Writes that grow the file are expected to update the file size
+	// (as seen through Attr). Note that file size changes are
+	// communicated also through Setattr.
+	Write(ctx context.Context, req *fuse.WriteRequest, resp *fuse.WriteResponse) error
+}
+
+type HandleReleaser interface {
+	Release(ctx context.Context, req *fuse.ReleaseRequest) error
+}
+
+type Config struct {
+	// Function to send debug log messages to. If nil, use fuse.Debug.
+	// Note that changing this or fuse.Debug may not affect existing
+	// calls to Serve.
+	//
+	// See fuse.Debug for the rules that log functions must follow.
+	Debug func(msg interface{})
+
+	// Function to put things into context for processing the request.
+	// The returned context must have ctx as its parent.
+	//
+	// Note that changing this may not affect existing calls to Serve.
+	//
+	// Must not retain req.
+	WithContext func(ctx context.Context, req fuse.Request) context.Context
+}
+
+// New returns a new FUSE server ready to serve this kernel FUSE
+// connection.
+//
+// Config may be nil.
+func New(conn *fuse.Conn, config *Config) *Server {
+	s := &Server{
+		conn:         conn,
+		req:          map[fuse.RequestID]*serveRequest{},
+		nodeRef:      map[Node]fuse.NodeID{},
+		dynamicInode: GenerateDynamicInode,
+	}
+	if config != nil {
+		s.debug = config.Debug
+		s.context = config.WithContext
+	}
+	if s.debug == nil {
+		s.debug = fuse.Debug
+	}
+	return s
+}
+
+type Server struct {
+	// set in New
+	conn    *fuse.Conn
+	debug   func(msg interface{})
+	context func(ctx context.Context, req fuse.Request) context.Context
+
+	// set once at Serve time
+	fs           FS
+	dynamicInode func(parent uint64, name string) uint64
+
+	// state, protected by meta
+	meta       sync.Mutex
+	req        map[fuse.RequestID]*serveRequest
+	node       []*serveNode
+	nodeRef    map[Node]fuse.NodeID
+	handle     []*serveHandle
+	freeNode   []fuse.NodeID
+	freeHandle []fuse.HandleID
+	nodeGen    uint64
+
+	// Used to ensure worker goroutines finish before Serve returns
+	wg sync.WaitGroup
+}
+
+// Serve serves the FUSE connection by making calls to the methods
+// of fs and the Nodes and Handles it makes available.  It returns only
+// when the connection has been closed or an unexpected error occurs.
+func (s *Server) Serve(fs FS) error {
+	defer s.wg.Wait() // Wait for worker goroutines to complete before return
+
+	s.fs = fs
+	if dyn, ok := fs.(FSInodeGenerator); ok {
+		s.dynamicInode = dyn.GenerateInode
+	}
+
+	root, err := fs.Root()
+	if err != nil {
+		return fmt.Errorf("cannot obtain root node: %v", err)
+	}
+	// Recognize the root node if it's ever returned from Lookup,
+	// passed to Invalidate, etc.
+	s.nodeRef[root] = 1
+	s.node = append(s.node, nil, &serveNode{
+		inode:      1,
+		generation: s.nodeGen,
+		node:       root,
+		refs:       1,
+	})
+	s.handle = append(s.handle, nil)
+
+	for {
+		req, err := s.conn.ReadRequest()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+
+		s.wg.Add(1)
+		go func() {
+			defer s.wg.Done()
+			s.serve(req)
+		}()
+	}
+	return nil
+}
+
+// Serve serves a FUSE connection with the default settings. See
+// Server.Serve.
+func Serve(c *fuse.Conn, fs FS) error {
+	server := New(c, nil)
+	return server.Serve(fs)
+}
+
+type nothing struct{}
+
+type serveRequest struct {
+	Request fuse.Request
+	cancel  func()
+}
+
+type serveNode struct {
+	inode      uint64
+	generation uint64
+	node       Node
+	refs       uint64
+
+	// Delay freeing the NodeID until waitgroup is done. This allows
+	// using the NodeID for short periods of time without holding the
+	// Server.meta lock.
+	//
+	// Rules:
+	//
+	//     - hold Server.meta while calling wg.Add, then unlock
+	//     - do NOT try to reacquire Server.meta
+	wg sync.WaitGroup
+}
+
+func (sn *serveNode) attr(ctx context.Context, attr *fuse.Attr) error {
+	err := nodeAttr(ctx, sn.node, attr)
+	if attr.Inode == 0 {
+		attr.Inode = sn.inode
+	}
+	return err
+}
+
+type serveHandle struct {
+	handle   Handle
+	readData []byte
+	nodeID   fuse.NodeID
+}
+
+// NodeRef is deprecated. It remains here to decrease code churn on
+// FUSE library users. You may remove it from your program now;
+// returning the same Node values are now recognized automatically,
+// without needing NodeRef.
+type NodeRef struct{}
+
+func (c *Server) saveNode(inode uint64, node Node) (id fuse.NodeID, gen uint64) {
+	c.meta.Lock()
+	defer c.meta.Unlock()
+
+	if id, ok := c.nodeRef[node]; ok {
+		sn := c.node[id]
+		sn.refs++
+		return id, sn.generation
+	}
+
+	sn := &serveNode{inode: inode, node: node, refs: 1}
+	if n := len(c.freeNode); n > 0 {
+		id = c.freeNode[n-1]
+		c.freeNode = c.freeNode[:n-1]
+		c.node[id] = sn
+		c.nodeGen++
+	} else {
+		id = fuse.NodeID(len(c.node))
+		c.node = append(c.node, sn)
+	}
+	sn.generation = c.nodeGen
+	c.nodeRef[node] = id
+	return id, sn.generation
+}
+
+func (c *Server) saveHandle(handle Handle, nodeID fuse.NodeID) (id fuse.HandleID) {
+	c.meta.Lock()
+	shandle := &serveHandle{handle: handle, nodeID: nodeID}
+	if n := len(c.freeHandle); n > 0 {
+		id = c.freeHandle[n-1]
+		c.freeHandle = c.freeHandle[:n-1]
+		c.handle[id] = shandle
+	} else {
+		id = fuse.HandleID(len(c.handle))
+		c.handle = append(c.handle, shandle)
+	}
+	c.meta.Unlock()
+	return
+}
+
+type nodeRefcountDropBug struct {
+	N    uint64
+	Refs uint64
+	Node fuse.NodeID
+}
+
+func (n *nodeRefcountDropBug) String() string {
+	return fmt.Sprintf("bug: trying to drop %d of %d references to %v", n.N, n.Refs, n.Node)
+}
+
+func (c *Server) dropNode(id fuse.NodeID, n uint64) (forget bool) {
+	c.meta.Lock()
+	defer c.meta.Unlock()
+	snode := c.node[id]
+
+	if snode == nil {
+		// this should only happen if refcounts kernel<->us disagree
+		// *and* two ForgetRequests for the same node race each other;
+		// this indicates a bug somewhere
+		c.debug(nodeRefcountDropBug{N: n, Node: id})
+
+		// we may end up triggering Forget twice, but that's better
+		// than not even once, and that's the best we can do
+		return true
+	}
+
+	if n > snode.refs {
+		c.debug(nodeRefcountDropBug{N: n, Refs: snode.refs, Node: id})
+		n = snode.refs
+	}
+
+	snode.refs -= n
+	if snode.refs == 0 {
+		snode.wg.Wait()
+		c.node[id] = nil
+		delete(c.nodeRef, snode.node)
+		c.freeNode = append(c.freeNode, id)
+		return true
+	}
+	return false
+}
+
+func (c *Server) dropHandle(id fuse.HandleID) {
+	c.meta.Lock()
+	c.handle[id] = nil
+	c.freeHandle = append(c.freeHandle, id)
+	c.meta.Unlock()
+}
+
+type missingHandle struct {
+	Handle    fuse.HandleID
+	MaxHandle fuse.HandleID
+}
+
+func (m missingHandle) String() string {
+	return fmt.Sprint("missing handle: ", m.Handle, m.MaxHandle)
+}
+
+// Returns nil for invalid handles.
+func (c *Server) getHandle(id fuse.HandleID) (shandle *serveHandle) {
+	c.meta.Lock()
+	defer c.meta.Unlock()
+	if id < fuse.HandleID(len(c.handle)) {
+		shandle = c.handle[uint(id)]
+	}
+	if shandle == nil {
+		c.debug(missingHandle{
+			Handle:    id,
+			MaxHandle: fuse.HandleID(len(c.handle)),
+		})
+	}
+	return
+}
+
+type request struct {
+	Op      string
+	Request *fuse.Header
+	In      interface{} `json:",omitempty"`
+}
+
+func (r request) String() string {
+	return fmt.Sprintf("<- %s", r.In)
+}
+
+type logResponseHeader struct {
+	ID fuse.RequestID
+}
+
+func (m logResponseHeader) String() string {
+	return fmt.Sprintf("ID=%v", m.ID)
+}
+
+type response struct {
+	Op      string
+	Request logResponseHeader
+	Out     interface{} `json:",omitempty"`
+	// Errno contains the errno value as a string, for example "EPERM".
+	Errno string `json:",omitempty"`
+	// Error may contain a free form error message.
+	Error string `json:",omitempty"`
+}
+
+func (r response) errstr() string {
+	s := r.Errno
+	if r.Error != "" {
+		// prefix the errno constant to the long form message
+		s = s + ": " + r.Error
+	}
+	return s
+}
+
+func (r response) String() string {
+	switch {
+	case r.Errno != "" && r.Out != nil:
+		return fmt.Sprintf("-> [%v] %v error=%s", r.Request, r.Out, r.errstr())
+	case r.Errno != "":
+		return fmt.Sprintf("-> [%v] %s error=%s", r.Request, r.Op, r.errstr())
+	case r.Out != nil:
+		// make sure (seemingly) empty values are readable
+		switch r.Out.(type) {
+		case string:
+			return fmt.Sprintf("-> [%v] %s %q", r.Request, r.Op, r.Out)
+		case []byte:
+			return fmt.Sprintf("-> [%v] %s [% x]", r.Request, r.Op, r.Out)
+		default:
+			return fmt.Sprintf("-> [%v] %v", r.Request, r.Out)
+		}
+	default:
+		return fmt.Sprintf("-> [%v] %s", r.Request, r.Op)
+	}
+}
+
+type notification struct {
+	Op   string
+	Node fuse.NodeID
+	Out  interface{} `json:",omitempty"`
+	Err  string      `json:",omitempty"`
+}
+
+func (n notification) String() string {
+	var buf bytes.Buffer
+	fmt.Fprintf(&buf, "=> %s %v", n.Op, n.Node)
+	if n.Out != nil {
+		// make sure (seemingly) empty values are readable
+		switch n.Out.(type) {
+		case string:
+			fmt.Fprintf(&buf, " %q", n.Out)
+		case []byte:
+			fmt.Fprintf(&buf, " [% x]", n.Out)
+		default:
+			fmt.Fprintf(&buf, " %s", n.Out)
+		}
+	}
+	if n.Err != "" {
+		fmt.Fprintf(&buf, " Err:%v", n.Err)
+	}
+	return buf.String()
+}
+
+type logMissingNode struct {
+	MaxNode fuse.NodeID
+}
+
+func opName(req fuse.Request) string {
+	t := reflect.Indirect(reflect.ValueOf(req)).Type()
+	s := t.Name()
+	s = strings.TrimSuffix(s, "Request")
+	return s
+}
+
+type logLinkRequestOldNodeNotFound struct {
+	Request *fuse.Header
+	In      *fuse.LinkRequest
+}
+
+func (m *logLinkRequestOldNodeNotFound) String() string {
+	return fmt.Sprintf("In LinkRequest (request %v), node %d not found", m.Request.Hdr().ID, m.In.OldNode)
+}
+
+type renameNewDirNodeNotFound struct {
+	Request *fuse.Header
+	In      *fuse.RenameRequest
+}
+
+func (m *renameNewDirNodeNotFound) String() string {
+	return fmt.Sprintf("In RenameRequest (request %v), node %d not found", m.Request.Hdr().ID, m.In.NewDir)
+}
+
+type handlerPanickedError struct {
+	Request interface{}
+	Err     interface{}
+}
+
+var _ error = handlerPanickedError{}
+
+func (h handlerPanickedError) Error() string {
+	return fmt.Sprintf("handler panicked: %v", h.Err)
+}
+
+var _ fuse.ErrorNumber = handlerPanickedError{}
+
+func (h handlerPanickedError) Errno() fuse.Errno {
+	if err, ok := h.Err.(fuse.ErrorNumber); ok {
+		return err.Errno()
+	}
+	return fuse.DefaultErrno
+}
+
+// handlerTerminatedError happens when a handler terminates itself
+// with runtime.Goexit. This is most commonly because of incorrect use
+// of testing.TB.FailNow, typically via t.Fatal.
+type handlerTerminatedError struct {
+	Request interface{}
+}
+
+var _ error = handlerTerminatedError{}
+
+func (h handlerTerminatedError) Error() string {
+	return fmt.Sprintf("handler terminated (called runtime.Goexit)")
+}
+
+var _ fuse.ErrorNumber = handlerTerminatedError{}
+
+func (h handlerTerminatedError) Errno() fuse.Errno {
+	return fuse.DefaultErrno
+}
+
+type handleNotReaderError struct {
+	handle Handle
+}
+
+var _ error = handleNotReaderError{}
+
+func (e handleNotReaderError) Error() string {
+	return fmt.Sprintf("handle has no Read: %T", e.handle)
+}
+
+var _ fuse.ErrorNumber = handleNotReaderError{}
+
+func (e handleNotReaderError) Errno() fuse.Errno {
+	return fuse.ENOTSUP
+}
+
+func initLookupResponse(s *fuse.LookupResponse) {
+	s.EntryValid = entryValidTime
+}
+
+func (c *Server) serve(r fuse.Request) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	parentCtx := ctx
+	if c.context != nil {
+		ctx = c.context(ctx, r)
+	}
+
+	req := &serveRequest{Request: r, cancel: cancel}
+
+	c.debug(request{
+		Op:      opName(r),
+		Request: r.Hdr(),
+		In:      r,
+	})
+	var node Node
+	var snode *serveNode
+	c.meta.Lock()
+	hdr := r.Hdr()
+	if id := hdr.Node; id != 0 {
+		if id < fuse.NodeID(len(c.node)) {
+			snode = c.node[uint(id)]
+		}
+		if snode == nil {
+			c.meta.Unlock()
+			c.debug(response{
+				Op:      opName(r),
+				Request: logResponseHeader{ID: hdr.ID},
+				Error:   fuse.ESTALE.ErrnoName(),
+				// this is the only place that sets both Error and
+				// Out; not sure if i want to do that; might get rid
+				// of len(c.node) things altogether
+				Out: logMissingNode{
+					MaxNode: fuse.NodeID(len(c.node)),
+				},
+			})
+			r.RespondError(fuse.ESTALE)
+			return
+		}
+		node = snode.node
+	}
+	if c.req[hdr.ID] != nil {
+		// This happens with OSXFUSE.  Assume it's okay and
+		// that we'll never see an interrupt for this one.
+		// Otherwise everything wedges.  TODO: Report to OSXFUSE?
+		//
+		// TODO this might have been because of missing done() calls
+	} else {
+		c.req[hdr.ID] = req
+	}
+	c.meta.Unlock()
+
+	// Call this before responding.
+	// After responding is too late: we might get another request
+	// with the same ID and be very confused.
+	done := func(resp interface{}) {
+		msg := response{
+			Op:      opName(r),
+			Request: logResponseHeader{ID: hdr.ID},
+		}
+		if err, ok := resp.(error); ok {
+			msg.Error = err.Error()
+			if ferr, ok := err.(fuse.ErrorNumber); ok {
+				errno := ferr.Errno()
+				msg.Errno = errno.ErrnoName()
+				if errno == err {
+					// it's just a fuse.Errno with no extra detail;
+					// skip the textual message for log readability
+					msg.Error = ""
+				}
+			} else {
+				msg.Errno = fuse.DefaultErrno.ErrnoName()
+			}
+		} else {
+			msg.Out = resp
+		}
+		c.debug(msg)
+
+		c.meta.Lock()
+		delete(c.req, hdr.ID)
+		c.meta.Unlock()
+	}
+
+	var responded bool
+	defer func() {
+		if rec := recover(); rec != nil {
+			const size = 1 << 16
+			buf := make([]byte, size)
+			n := runtime.Stack(buf, false)
+			buf = buf[:n]
+			log.Printf("fuse: panic in handler for %v: %v\n%s", r, rec, buf)
+			err := handlerPanickedError{
+				Request: r,
+				Err:     rec,
+			}
+			done(err)
+			r.RespondError(err)
+			return
+		}
+
+		if !responded {
+			err := handlerTerminatedError{
+				Request: r,
+			}
+			done(err)
+			r.RespondError(err)
+		}
+	}()
+
+	if err := c.handleRequest(ctx, node, snode, r, done); err != nil {
+		if err == context.Canceled {
+			select {
+			case <-parentCtx.Done():
+				// We canceled the parent context because of an
+				// incoming interrupt request, so return EINTR
+				// to trigger the right behavior in the client app.
+				//
+				// Only do this when it's the parent context that was
+				// canceled, not a context controlled by the program
+				// using this library, so we don't return EINTR too
+				// eagerly -- it might cause busy loops.
+				//
+				// Decent write-up on role of EINTR:
+				// http://250bpm.com/blog:12
+				err = fuse.EINTR
+			default:
+				// nothing
+			}
+		}
+		done(err)
+		r.RespondError(err)
+	}
+
+	// disarm runtime.Goexit protection
+	responded = true
+}
+
+// handleRequest will either a) call done(s) and r.Respond(s) OR b) return an error.
+func (c *Server) handleRequest(ctx context.Context, node Node, snode *serveNode, r fuse.Request, done func(resp interface{})) error {
+	switch r := r.(type) {
+	default:
+		// Note: To FUSE, ENOSYS means "this server never implements this request."
+		// It would be inappropriate to return ENOSYS for other operations in this
+		// switch that might only be unavailable in some contexts, not all.
+		return fuse.ENOSYS
+
+	case *fuse.StatfsRequest:
+		s := &fuse.StatfsResponse{}
+		if fs, ok := c.fs.(FSStatfser); ok {
+			if err := fs.Statfs(ctx, r, s); err != nil {
+				return err
+			}
+		}
+		done(s)
+		r.Respond(s)
+		return nil
+
+	// Node operations.
+	case *fuse.GetattrRequest:
+		s := &fuse.GetattrResponse{}
+		if n, ok := node.(NodeGetattrer); ok {
+			if err := n.Getattr(ctx, r, s); err != nil {
+				return err
+			}
+		} else {
+			if err := snode.attr(ctx, &s.Attr); err != nil {
+				return err
+			}
+		}
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.SetattrRequest:
+		s := &fuse.SetattrResponse{}
+		if n, ok := node.(NodeSetattrer); ok {
+			if err := n.Setattr(ctx, r, s); err != nil {
+				return err
+			}
+		}
+
+		if err := snode.attr(ctx, &s.Attr); err != nil {
+			return err
+		}
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.SymlinkRequest:
+		s := &fuse.SymlinkResponse{}
+		initLookupResponse(&s.LookupResponse)
+		n, ok := node.(NodeSymlinker)
+		if !ok {
+			return fuse.EIO // XXX or EPERM like Mkdir?
+		}
+		n2, err := n.Symlink(ctx, r)
+		if err != nil {
+			return err
+		}
+		if err := c.saveLookup(ctx, &s.LookupResponse, snode, r.NewName, n2); err != nil {
+			return err
+		}
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.ReadlinkRequest:
+		n, ok := node.(NodeReadlinker)
+		if !ok {
+			return fuse.EIO /// XXX or EPERM?
+		}
+		target, err := n.Readlink(ctx, r)
+		if err != nil {
+			return err
+		}
+		done(target)
+		r.Respond(target)
+		return nil
+
+	case *fuse.LinkRequest:
+		n, ok := node.(NodeLinker)
+		if !ok {
+			return fuse.EIO /// XXX or EPERM?
+		}
+		c.meta.Lock()
+		var oldNode *serveNode
+		if int(r.OldNode) < len(c.node) {
+			oldNode = c.node[r.OldNode]
+		}
+		c.meta.Unlock()
+		if oldNode == nil {
+			c.debug(logLinkRequestOldNodeNotFound{
+				Request: r.Hdr(),
+				In:      r,
+			})
+			return fuse.EIO
+		}
+		n2, err := n.Link(ctx, r, oldNode.node)
+		if err != nil {
+			return err
+		}
+		s := &fuse.LookupResponse{}
+		initLookupResponse(s)
+		if err := c.saveLookup(ctx, s, snode, r.NewName, n2); err != nil {
+			return err
+		}
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.RemoveRequest:
+		n, ok := node.(NodeRemover)
+		if !ok {
+			return fuse.EIO /// XXX or EPERM?
+		}
+		err := n.Remove(ctx, r)
+		if err != nil {
+			return err
+		}
+		done(nil)
+		r.Respond()
+		return nil
+
+	case *fuse.AccessRequest:
+		if n, ok := node.(NodeAccesser); ok {
+			if err := n.Access(ctx, r); err != nil {
+				return err
+			}
+		}
+		done(nil)
+		r.Respond()
+		return nil
+
+	case *fuse.LookupRequest:
+		var n2 Node
+		var err error
+		s := &fuse.LookupResponse{}
+		initLookupResponse(s)
+		if n, ok := node.(NodeStringLookuper); ok {
+			n2, err = n.Lookup(ctx, r.Name)
+		} else if n, ok := node.(NodeRequestLookuper); ok {
+			n2, err = n.Lookup(ctx, r, s)
+		} else {
+			return fuse.ENOENT
+		}
+		if err != nil {
+			return err
+		}
+		if err := c.saveLookup(ctx, s, snode, r.Name, n2); err != nil {
+			return err
+		}
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.MkdirRequest:
+		s := &fuse.MkdirResponse{}
+		initLookupResponse(&s.LookupResponse)
+		n, ok := node.(NodeMkdirer)
+		if !ok {
+			return fuse.EPERM
+		}
+		n2, err := n.Mkdir(ctx, r)
+		if err != nil {
+			return err
+		}
+		if err := c.saveLookup(ctx, &s.LookupResponse, snode, r.Name, n2); err != nil {
+			return err
+		}
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.OpenRequest:
+		s := &fuse.OpenResponse{}
+		var h2 Handle
+		if n, ok := node.(NodeOpener); ok {
+			hh, err := n.Open(ctx, r, s)
+			if err != nil {
+				return err
+			}
+			h2 = hh
+		} else {
+			h2 = node
+		}
+		s.Handle = c.saveHandle(h2, r.Hdr().Node)
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.CreateRequest:
+		n, ok := node.(NodeCreater)
+		if !ok {
+			// If we send back ENOSYS, FUSE will try mknod+open.
+			return fuse.EPERM
+		}
+		s := &fuse.CreateResponse{OpenResponse: fuse.OpenResponse{}}
+		initLookupResponse(&s.LookupResponse)
+		n2, h2, err := n.Create(ctx, r, s)
+		if err != nil {
+			return err
+		}
+		if err := c.saveLookup(ctx, &s.LookupResponse, snode, r.Name, n2); err != nil {
+			return err
+		}
+		s.Handle = c.saveHandle(h2, r.Hdr().Node)
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.GetxattrRequest:
+		n, ok := node.(NodeGetxattrer)
+		if !ok {
+			return fuse.ENOTSUP
+		}
+		s := &fuse.GetxattrResponse{}
+		err := n.Getxattr(ctx, r, s)
+		if err != nil {
+			return err
+		}
+		if r.Size != 0 && uint64(len(s.Xattr)) > uint64(r.Size) {
+			return fuse.ERANGE
+		}
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.ListxattrRequest:
+		n, ok := node.(NodeListxattrer)
+		if !ok {
+			return fuse.ENOTSUP
+		}
+		s := &fuse.ListxattrResponse{}
+		err := n.Listxattr(ctx, r, s)
+		if err != nil {
+			return err
+		}
+		if r.Size != 0 && uint64(len(s.Xattr)) > uint64(r.Size) {
+			return fuse.ERANGE
+		}
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.SetxattrRequest:
+		n, ok := node.(NodeSetxattrer)
+		if !ok {
+			return fuse.ENOTSUP
+		}
+		err := n.Setxattr(ctx, r)
+		if err != nil {
+			return err
+		}
+		done(nil)
+		r.Respond()
+		return nil
+
+	case *fuse.RemovexattrRequest:
+		n, ok := node.(NodeRemovexattrer)
+		if !ok {
+			return fuse.ENOTSUP
+		}
+		err := n.Removexattr(ctx, r)
+		if err != nil {
+			return err
+		}
+		done(nil)
+		r.Respond()
+		return nil
+
+	case *fuse.ForgetRequest:
+		forget := c.dropNode(r.Hdr().Node, r.N)
+		if forget {
+			n, ok := node.(NodeForgetter)
+			if ok {
+				n.Forget()
+			}
+		}
+		done(nil)
+		r.Respond()
+		return nil
+
+	// Handle operations.
+	case *fuse.ReadRequest:
+		shandle := c.getHandle(r.Handle)
+		if shandle == nil {
+			return fuse.ESTALE
+		}
+		handle := shandle.handle
+
+		s := &fuse.ReadResponse{Data: make([]byte, 0, r.Size)}
+		if r.Dir {
+			if h, ok := handle.(HandleReadDirAller); ok {
+				// detect rewinddir(3) or similar seek and refresh
+				// contents
+				if r.Offset == 0 {
+					shandle.readData = nil
+				}
+
+				if shandle.readData == nil {
+					dirs, err := h.ReadDirAll(ctx)
+					if err != nil {
+						return err
+					}
+					var data []byte
+					for _, dir := range dirs {
+						if dir.Inode == 0 {
+							dir.Inode = c.dynamicInode(snode.inode, dir.Name)
+						}
+						data = fuse.AppendDirent(data, dir)
+					}
+					shandle.readData = data
+				}
+				fuseutil.HandleRead(r, s, shandle.readData)
+				done(s)
+				r.Respond(s)
+				return nil
+			}
+		} else {
+			if h, ok := handle.(HandleReadAller); ok {
+				if shandle.readData == nil {
+					data, err := h.ReadAll(ctx)
+					if err != nil {
+						return err
+					}
+					if data == nil {
+						data = []byte{}
+					}
+					shandle.readData = data
+				}
+				fuseutil.HandleRead(r, s, shandle.readData)
+				done(s)
+				r.Respond(s)
+				return nil
+			}
+			h, ok := handle.(HandleReader)
+			if !ok {
+				err := handleNotReaderError{handle: handle}
+				return err
+			}
+			if err := h.Read(ctx, r, s); err != nil {
+				return err
+			}
+		}
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.WriteRequest:
+		shandle := c.getHandle(r.Handle)
+		if shandle == nil {
+			return fuse.ESTALE
+		}
+
+		s := &fuse.WriteResponse{}
+		if h, ok := shandle.handle.(HandleWriter); ok {
+			if err := h.Write(ctx, r, s); err != nil {
+				return err
+			}
+			done(s)
+			r.Respond(s)
+			return nil
+		}
+		return fuse.EIO
+
+	case *fuse.FlushRequest:
+		shandle := c.getHandle(r.Handle)
+		if shandle == nil {
+			return fuse.ESTALE
+		}
+		handle := shandle.handle
+
+		if h, ok := handle.(HandleFlusher); ok {
+			if err := h.Flush(ctx, r); err != nil {
+				return err
+			}
+		}
+		done(nil)
+		r.Respond()
+		return nil
+
+	case *fuse.ReleaseRequest:
+		shandle := c.getHandle(r.Handle)
+		if shandle == nil {
+			return fuse.ESTALE
+		}
+		handle := shandle.handle
+
+		// No matter what, release the handle.
+		c.dropHandle(r.Handle)
+
+		if h, ok := handle.(HandleReleaser); ok {
+			if err := h.Release(ctx, r); err != nil {
+				return err
+			}
+		}
+		done(nil)
+		r.Respond()
+		return nil
+
+	case *fuse.DestroyRequest:
+		if fs, ok := c.fs.(FSDestroyer); ok {
+			fs.Destroy()
+		}
+		done(nil)
+		r.Respond()
+		return nil
+
+	case *fuse.RenameRequest:
+		c.meta.Lock()
+		var newDirNode *serveNode
+		if int(r.NewDir) < len(c.node) {
+			newDirNode = c.node[r.NewDir]
+		}
+		c.meta.Unlock()
+		if newDirNode == nil {
+			c.debug(renameNewDirNodeNotFound{
+				Request: r.Hdr(),
+				In:      r,
+			})
+			return fuse.EIO
+		}
+		n, ok := node.(NodeRenamer)
+		if !ok {
+			return fuse.EIO // XXX or EPERM like Mkdir?
+		}
+		err := n.Rename(ctx, r, newDirNode.node)
+		if err != nil {
+			return err
+		}
+		done(nil)
+		r.Respond()
+		return nil
+
+	case *fuse.MknodRequest:
+		n, ok := node.(NodeMknoder)
+		if !ok {
+			return fuse.EIO
+		}
+		n2, err := n.Mknod(ctx, r)
+		if err != nil {
+			return err
+		}
+		s := &fuse.LookupResponse{}
+		initLookupResponse(s)
+		if err := c.saveLookup(ctx, s, snode, r.Name, n2); err != nil {
+			return err
+		}
+		done(s)
+		r.Respond(s)
+		return nil
+
+	case *fuse.FsyncRequest:
+		n, ok := node.(NodeFsyncer)
+		if !ok {
+			return fuse.EIO
+		}
+		err := n.Fsync(ctx, r)
+		if err != nil {
+			return err
+		}
+		done(nil)
+		r.Respond()
+		return nil
+
+	case *fuse.InterruptRequest:
+		c.meta.Lock()
+		ireq := c.req[r.IntrID]
+		if ireq != nil && ireq.cancel != nil {
+			ireq.cancel()
+			ireq.cancel = nil
+		}
+		c.meta.Unlock()
+		done(nil)
+		r.Respond()
+		return nil
+
+		/*	case *FsyncdirRequest:
+				return ENOSYS
+
+			case *GetlkRequest, *SetlkRequest, *SetlkwRequest:
+				return ENOSYS
+
+			case *BmapRequest:
+				return ENOSYS
+
+			case *SetvolnameRequest, *GetxtimesRequest, *ExchangeRequest:
+				return ENOSYS
+		*/
+	}
+
+	panic("not reached")
+}
+
+func (c *Server) saveLookup(ctx context.Context, s *fuse.LookupResponse, snode *serveNode, elem string, n2 Node) error {
+	if err := nodeAttr(ctx, n2, &s.Attr); err != nil {
+		return err
+	}
+	if s.Attr.Inode == 0 {
+		s.Attr.Inode = c.dynamicInode(snode.inode, elem)
+	}
+
+	s.Node, s.Generation = c.saveNode(s.Attr.Inode, n2)
+	return nil
+}
+
+type invalidateNodeDetail struct {
+	Off  int64
+	Size int64
+}
+
+func (i invalidateNodeDetail) String() string {
+	return fmt.Sprintf("Off:%d Size:%d", i.Off, i.Size)
+}
+
+func errstr(err error) string {
+	if err == nil {
+		return ""
+	}
+	return err.Error()
+}
+
+func (s *Server) invalidateNode(node Node, off int64, size int64) error {
+	s.meta.Lock()
+	id, ok := s.nodeRef[node]
+	if ok {
+		snode := s.node[id]
+		snode.wg.Add(1)
+		defer snode.wg.Done()
+	}
+	s.meta.Unlock()
+	if !ok {
+		// This is what the kernel would have said, if we had been
+		// able to send this message; it's not cached.
+		return fuse.ErrNotCached
+	}
+	// Delay logging until after we can record the error too. We
+	// consider a /dev/fuse write to be instantaneous enough to not
+	// need separate before and after messages.
+	err := s.conn.InvalidateNode(id, off, size)
+	s.debug(notification{
+		Op:   "InvalidateNode",
+		Node: id,
+		Out: invalidateNodeDetail{
+			Off:  off,
+			Size: size,
+		},
+		Err: errstr(err),
+	})
+	return err
+}
+
+// InvalidateNodeAttr invalidates the kernel cache of the attributes
+// of node.
+//
+// Returns fuse.ErrNotCached if the kernel is not currently caching
+// the node.
+func (s *Server) InvalidateNodeAttr(node Node) error {
+	return s.invalidateNode(node, 0, 0)
+}
+
+// InvalidateNodeData invalidates the kernel cache of the attributes
+// and data of node.
+//
+// Returns fuse.ErrNotCached if the kernel is not currently caching
+// the node.
+func (s *Server) InvalidateNodeData(node Node) error {
+	return s.invalidateNode(node, 0, -1)
+}
+
+// InvalidateNodeDataRange invalidates the kernel cache of the
+// attributes and a range of the data of node.
+//
+// Returns fuse.ErrNotCached if the kernel is not currently caching
+// the node.
+func (s *Server) InvalidateNodeDataRange(node Node, off int64, size int64) error {
+	return s.invalidateNode(node, off, size)
+}
+
+type invalidateEntryDetail struct {
+	Name string
+}
+
+func (i invalidateEntryDetail) String() string {
+	return fmt.Sprintf("%q", i.Name)
+}
+
+// InvalidateEntry invalidates the kernel cache of the directory entry
+// identified by parent node and entry basename.
+//
+// Kernel may or may not cache directory listings. To invalidate
+// those, use InvalidateNode to invalidate all of the data for a
+// directory. (As of 2015-06, Linux FUSE does not cache directory
+// listings.)
+//
+// Returns ErrNotCached if the kernel is not currently caching the
+// node.
+func (s *Server) InvalidateEntry(parent Node, name string) error {
+	s.meta.Lock()
+	id, ok := s.nodeRef[parent]
+	if ok {
+		snode := s.node[id]
+		snode.wg.Add(1)
+		defer snode.wg.Done()
+	}
+	s.meta.Unlock()
+	if !ok {
+		// This is what the kernel would have said, if we had been
+		// able to send this message; it's not cached.
+		return fuse.ErrNotCached
+	}
+	err := s.conn.InvalidateEntry(id, name)
+	s.debug(notification{
+		Op:   "InvalidateEntry",
+		Node: id,
+		Out: invalidateEntryDetail{
+			Name: name,
+		},
+		Err: errstr(err),
+	})
+	return err
+}
+
+// DataHandle returns a read-only Handle that satisfies reads
+// using the given data.
+func DataHandle(data []byte) Handle {
+	return &dataHandle{data}
+}
+
+type dataHandle struct {
+	data []byte
+}
+
+func (d *dataHandle) ReadAll(ctx context.Context) ([]byte, error) {
+	return d.data, nil
+}
+
+// GenerateDynamicInode returns a dynamic inode.
+//
+// The parent inode and current entry name are used as the criteria
+// for choosing a pseudorandom inode. This makes it likely the same
+// entry will get the same inode on multiple runs.
+func GenerateDynamicInode(parent uint64, name string) uint64 {
+	h := fnv.New64a()
+	var buf [8]byte
+	binary.LittleEndian.PutUint64(buf[:], parent)
+	_, _ = h.Write(buf[:])
+	_, _ = h.Write([]byte(name))
+	var inode uint64
+	for {
+		inode = h.Sum64()
+		if inode != 0 {
+			break
+		}
+		// there's a tiny probability that result is zero; change the
+		// input a little and try again
+		_, _ = h.Write([]byte{'x'})
+	}
+	return inode
+}
diff --git a/vendor/bazil.org/fuse/fs/tree.go b/vendor/bazil.org/fuse/fs/tree.go
new file mode 100644
index 000000000..7e078045a
--- /dev/null
+++ b/vendor/bazil.org/fuse/fs/tree.go
@@ -0,0 +1,99 @@
+// FUSE directory tree, for servers that wish to use it with the service loop.
+
+package fs
+
+import (
+	"os"
+	pathpkg "path"
+	"strings"
+
+	"golang.org/x/net/context"
+)
+
+import (
+	"bazil.org/fuse"
+)
+
+// A Tree implements a basic read-only directory tree for FUSE.
+// The Nodes contained in it may still be writable.
+type Tree struct {
+	tree
+}
+
+func (t *Tree) Root() (Node, error) {
+	return &t.tree, nil
+}
+
+// Add adds the path to the tree, resolving to the given node.
+// If path or a prefix of path has already been added to the tree,
+// Add panics.
+//
+// Add is only safe to call before starting to serve requests.
+func (t *Tree) Add(path string, node Node) {
+	path = pathpkg.Clean("/" + path)[1:]
+	elems := strings.Split(path, "/")
+	dir := Node(&t.tree)
+	for i, elem := range elems {
+		dt, ok := dir.(*tree)
+		if !ok {
+			panic("fuse: Tree.Add for " + strings.Join(elems[:i], "/") + " and " + path)
+		}
+		n := dt.lookup(elem)
+		if n != nil {
+			if i+1 == len(elems) {
+				panic("fuse: Tree.Add for " + path + " conflicts with " + elem)
+			}
+			dir = n
+		} else {
+			if i+1 == len(elems) {
+				dt.add(elem, node)
+			} else {
+				dir = &tree{}
+				dt.add(elem, dir)
+			}
+		}
+	}
+}
+
+type treeDir struct {
+	name string
+	node Node
+}
+
+type tree struct {
+	dir []treeDir
+}
+
+func (t *tree) lookup(name string) Node {
+	for _, d := range t.dir {
+		if d.name == name {
+			return d.node
+		}
+	}
+	return nil
+}
+
+func (t *tree) add(name string, n Node) {
+	t.dir = append(t.dir, treeDir{name, n})
+}
+
+func (t *tree) Attr(ctx context.Context, a *fuse.Attr) error {
+	a.Mode = os.ModeDir | 0555
+	return nil
+}
+
+func (t *tree) Lookup(ctx context.Context, name string) (Node, error) {
+	n := t.lookup(name)
+	if n != nil {
+		return n, nil
+	}
+	return nil, fuse.ENOENT
+}
+
+func (t *tree) ReadDirAll(ctx context.Context) ([]fuse.Dirent, error) {
+	var out []fuse.Dirent
+	for _, d := range t.dir {
+		out = append(out, fuse.Dirent{Name: d.name})
+	}
+	return out, nil
+}
diff --git a/vendor/bazil.org/fuse/fuse.go b/vendor/bazil.org/fuse/fuse.go
new file mode 100644
index 000000000..7dc70f9e1
--- /dev/null
+++ b/vendor/bazil.org/fuse/fuse.go
@@ -0,0 +1,2304 @@
+// See the file LICENSE for copyright and licensing information.
+
+// Adapted from Plan 9 from User Space's src/cmd/9pfuse/fuse.c,
+// which carries this notice:
+//
+// The files in this directory are subject to the following license.
+//
+// The author of this software is Russ Cox.
+//
+//         Copyright (c) 2006 Russ Cox
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose without fee is hereby granted, provided that this entire notice
+// is included in all copies of any software which is or includes a copy
+// or modification of this software and in all copies of the supporting
+// documentation for such software.
+//
+// THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
+// WARRANTY.  IN PARTICULAR, THE AUTHOR MAKES NO REPRESENTATION OR WARRANTY
+// OF ANY KIND CONCERNING THE MERCHANTABILITY OF THIS SOFTWARE OR ITS
+// FITNESS FOR ANY PARTICULAR PURPOSE.
+
+// Package fuse enables writing FUSE file systems on Linux, OS X, and FreeBSD.
+//
+// On OS X, it requires OSXFUSE (http://osxfuse.github.com/).
+//
+// There are two approaches to writing a FUSE file system.  The first is to speak
+// the low-level message protocol, reading from a Conn using ReadRequest and
+// writing using the various Respond methods.  This approach is closest to
+// the actual interaction with the kernel and can be the simplest one in contexts
+// such as protocol translators.
+//
+// Servers of synthesized file systems tend to share common
+// bookkeeping abstracted away by the second approach, which is to
+// call fs.Serve to serve the FUSE protocol using an implementation of
+// the service methods in the interfaces FS* (file system), Node* (file
+// or directory), and Handle* (opened file or directory).
+// There are a daunting number of such methods that can be written,
+// but few are required.
+// The specific methods are described in the documentation for those interfaces.
+//
+// The hellofs subdirectory contains a simple illustration of the fs.Serve approach.
+//
+// Service Methods
+//
+// The required and optional methods for the FS, Node, and Handle interfaces
+// have the general form
+//
+//	Op(ctx context.Context, req *OpRequest, resp *OpResponse) error
+//
+// where Op is the name of a FUSE operation. Op reads request
+// parameters from req and writes results to resp. An operation whose
+// only result is the error result omits the resp parameter.
+//
+// Multiple goroutines may call service methods simultaneously; the
+// methods being called are responsible for appropriate
+// synchronization.
+//
+// The operation must not hold on to the request or response,
+// including any []byte fields such as WriteRequest.Data or
+// SetxattrRequest.Xattr.
+//
+// Errors
+//
+// Operations can return errors. The FUSE interface can only
+// communicate POSIX errno error numbers to file system clients, the
+// message is not visible to file system clients. The returned error
+// can implement ErrorNumber to control the errno returned. Without
+// ErrorNumber, a generic errno (EIO) is returned.
+//
+// Error messages will be visible in the debug log as part of the
+// response.
+//
+// Interrupted Operations
+//
+// In some file systems, some operations
+// may take an undetermined amount of time.  For example, a Read waiting for
+// a network message or a matching Write might wait indefinitely.  If the request
+// is cancelled and no longer needed, the context will be cancelled.
+// Blocking operations should select on a receive from ctx.Done() and attempt to
+// abort the operation early if the receive succeeds (meaning the channel is closed).
+// To indicate that the operation failed because it was aborted, return fuse.EINTR.
+//
+// If an operation does not block for an indefinite amount of time, supporting
+// cancellation is not necessary.
+//
+// Authentication
+//
+// All requests types embed a Header, meaning that the method can
+// inspect req.Pid, req.Uid, and req.Gid as necessary to implement
+// permission checking. The kernel FUSE layer normally prevents other
+// users from accessing the FUSE file system (to change this, see
+// AllowOther, AllowRoot), but does not enforce access modes (to
+// change this, see DefaultPermissions).
+//
+// Mount Options
+//
+// Behavior and metadata of the mounted file system can be changed by
+// passing MountOption values to Mount.
+//
+package fuse // import "bazil.org/fuse"
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"sync"
+	"syscall"
+	"time"
+	"unsafe"
+)
+
+// A Conn represents a connection to a mounted FUSE file system.
+type Conn struct {
+	// Ready is closed when the mount is complete or has failed.
+	Ready <-chan struct{}
+
+	// MountError stores any error from the mount process. Only valid
+	// after Ready is closed.
+	MountError error
+
+	// File handle for kernel communication. Only safe to access if
+	// rio or wio is held.
+	dev *os.File
+	wio sync.RWMutex
+	rio sync.RWMutex
+
+	// Protocol version negotiated with InitRequest/InitResponse.
+	proto Protocol
+}
+
+// MountpointDoesNotExistError is an error returned when the
+// mountpoint does not exist.
+type MountpointDoesNotExistError struct {
+	Path string
+}
+
+var _ error = (*MountpointDoesNotExistError)(nil)
+
+func (e *MountpointDoesNotExistError) Error() string {
+	return fmt.Sprintf("mountpoint does not exist: %v", e.Path)
+}
+
+// Mount mounts a new FUSE connection on the named directory
+// and returns a connection for reading and writing FUSE messages.
+//
+// After a successful return, caller must call Close to free
+// resources.
+//
+// Even on successful return, the new mount is not guaranteed to be
+// visible until after Conn.Ready is closed. See Conn.MountError for
+// possible errors. Incoming requests on Conn must be served to make
+// progress.
+func Mount(dir string, options ...MountOption) (*Conn, error) {
+	conf := mountConfig{
+		options: make(map[string]string),
+	}
+	for _, option := range options {
+		if err := option(&conf); err != nil {
+			return nil, err
+		}
+	}
+
+	ready := make(chan struct{}, 1)
+	c := &Conn{
+		Ready: ready,
+	}
+	f, err := mount(dir, &conf, ready, &c.MountError)
+	if err != nil {
+		return nil, err
+	}
+	c.dev = f
+
+	if err := initMount(c, &conf); err != nil {
+		c.Close()
+		if err == ErrClosedWithoutInit {
+			// see if we can provide a better error
+			<-c.Ready
+			if err := c.MountError; err != nil {
+				return nil, err
+			}
+		}
+		return nil, err
+	}
+
+	return c, nil
+}
+
+type OldVersionError struct {
+	Kernel     Protocol
+	LibraryMin Protocol
+}
+
+func (e *OldVersionError) Error() string {
+	return fmt.Sprintf("kernel FUSE version is too old: %v < %v", e.Kernel, e.LibraryMin)
+}
+
+var (
+	ErrClosedWithoutInit = errors.New("fuse connection closed without init")
+)
+
+func initMount(c *Conn, conf *mountConfig) error {
+	req, err := c.ReadRequest()
+	if err != nil {
+		if err == io.EOF {
+			return ErrClosedWithoutInit
+		}
+		return err
+	}
+	r, ok := req.(*InitRequest)
+	if !ok {
+		return fmt.Errorf("missing init, got: %T", req)
+	}
+
+	min := Protocol{protoVersionMinMajor, protoVersionMinMinor}
+	if r.Kernel.LT(min) {
+		req.RespondError(Errno(syscall.EPROTO))
+		c.Close()
+		return &OldVersionError{
+			Kernel:     r.Kernel,
+			LibraryMin: min,
+		}
+	}
+
+	proto := Protocol{protoVersionMaxMajor, protoVersionMaxMinor}
+	if r.Kernel.LT(proto) {
+		// Kernel doesn't support the latest version we have.
+		proto = r.Kernel
+	}
+	c.proto = proto
+
+	s := &InitResponse{
+		Library:      proto,
+		MaxReadahead: conf.maxReadahead,
+		MaxWrite:     maxWrite,
+		Flags:        InitBigWrites | conf.initFlags,
+	}
+	r.Respond(s)
+	return nil
+}
+
+// A Request represents a single FUSE request received from the kernel.
+// Use a type switch to determine the specific kind.
+// A request of unrecognized type will have concrete type *Header.
+type Request interface {
+	// Hdr returns the Header associated with this request.
+	Hdr() *Header
+
+	// RespondError responds to the request with the given error.
+	RespondError(error)
+
+	String() string
+}
+
+// A RequestID identifies an active FUSE request.
+type RequestID uint64
+
+func (r RequestID) String() string {
+	return fmt.Sprintf("%#x", uint64(r))
+}
+
+// A NodeID is a number identifying a directory or file.
+// It must be unique among IDs returned in LookupResponses
+// that have not yet been forgotten by ForgetRequests.
+type NodeID uint64
+
+func (n NodeID) String() string {
+	return fmt.Sprintf("%#x", uint64(n))
+}
+
+// A HandleID is a number identifying an open directory or file.
+// It only needs to be unique while the directory or file is open.
+type HandleID uint64
+
+func (h HandleID) String() string {
+	return fmt.Sprintf("%#x", uint64(h))
+}
+
+// The RootID identifies the root directory of a FUSE file system.
+const RootID NodeID = rootID
+
+// A Header describes the basic information sent in every request.
+type Header struct {
+	Conn *Conn     `json:"-"` // connection this request was received on
+	ID   RequestID // unique ID for request
+	Node NodeID    // file or directory the request is about
+	Uid  uint32    // user ID of process making request
+	Gid  uint32    // group ID of process making request
+	Pid  uint32    // process ID of process making request
+
+	// for returning to reqPool
+	msg *message
+}
+
+func (h *Header) String() string {
+	return fmt.Sprintf("ID=%v Node=%v Uid=%d Gid=%d Pid=%d", h.ID, h.Node, h.Uid, h.Gid, h.Pid)
+}
+
+func (h *Header) Hdr() *Header {
+	return h
+}
+
+func (h *Header) noResponse() {
+	putMessage(h.msg)
+}
+
+func (h *Header) respond(msg []byte) {
+	out := (*outHeader)(unsafe.Pointer(&msg[0]))
+	out.Unique = uint64(h.ID)
+	h.Conn.respond(msg)
+	putMessage(h.msg)
+}
+
+// An ErrorNumber is an error with a specific error number.
+//
+// Operations may return an error value that implements ErrorNumber to
+// control what specific error number (errno) to return.
+type ErrorNumber interface {
+	// Errno returns the the error number (errno) for this error.
+	Errno() Errno
+}
+
+const (
+	// ENOSYS indicates that the call is not supported.
+	ENOSYS = Errno(syscall.ENOSYS)
+
+	// ESTALE is used by Serve to respond to violations of the FUSE protocol.
+	ESTALE = Errno(syscall.ESTALE)
+
+	ENOENT = Errno(syscall.ENOENT)
+	EIO    = Errno(syscall.EIO)
+	EPERM  = Errno(syscall.EPERM)
+
+	// EINTR indicates request was interrupted by an InterruptRequest.
+	// See also fs.Intr.
+	EINTR = Errno(syscall.EINTR)
+
+	ERANGE  = Errno(syscall.ERANGE)
+	ENOTSUP = Errno(syscall.ENOTSUP)
+	EEXIST  = Errno(syscall.EEXIST)
+)
+
+// DefaultErrno is the errno used when error returned does not
+// implement ErrorNumber.
+const DefaultErrno = EIO
+
+var errnoNames = map[Errno]string{
+	ENOSYS: "ENOSYS",
+	ESTALE: "ESTALE",
+	ENOENT: "ENOENT",
+	EIO:    "EIO",
+	EPERM:  "EPERM",
+	EINTR:  "EINTR",
+	EEXIST: "EEXIST",
+}
+
+// Errno implements Error and ErrorNumber using a syscall.Errno.
+type Errno syscall.Errno
+
+var _ = ErrorNumber(Errno(0))
+var _ = error(Errno(0))
+
+func (e Errno) Errno() Errno {
+	return e
+}
+
+func (e Errno) String() string {
+	return syscall.Errno(e).Error()
+}
+
+func (e Errno) Error() string {
+	return syscall.Errno(e).Error()
+}
+
+// ErrnoName returns the short non-numeric identifier for this errno.
+// For example, "EIO".
+func (e Errno) ErrnoName() string {
+	s := errnoNames[e]
+	if s == "" {
+		s = fmt.Sprint(e.Errno())
+	}
+	return s
+}
+
+func (e Errno) MarshalText() ([]byte, error) {
+	s := e.ErrnoName()
+	return []byte(s), nil
+}
+
+func (h *Header) RespondError(err error) {
+	errno := DefaultErrno
+	if ferr, ok := err.(ErrorNumber); ok {
+		errno = ferr.Errno()
+	}
+	// FUSE uses negative errors!
+	// TODO: File bug report against OSXFUSE: positive error causes kernel panic.
+	buf := newBuffer(0)
+	hOut := (*outHeader)(unsafe.Pointer(&buf[0]))
+	hOut.Error = -int32(errno)
+	h.respond(buf)
+}
+
+// All requests read from the kernel, without data, are shorter than
+// this.
+var maxRequestSize = syscall.Getpagesize()
+var bufSize = maxRequestSize + maxWrite
+
+// reqPool is a pool of messages.
+//
+// Lifetime of a logical message is from getMessage to putMessage.
+// getMessage is called by ReadRequest. putMessage is called by
+// Conn.ReadRequest, Request.Respond, or Request.RespondError.
+//
+// Messages in the pool are guaranteed to have conn and off zeroed,
+// buf allocated and len==bufSize, and hdr set.
+var reqPool = sync.Pool{
+	New: allocMessage,
+}
+
+func allocMessage() interface{} {
+	m := &message{buf: make([]byte, bufSize)}
+	m.hdr = (*inHeader)(unsafe.Pointer(&m.buf[0]))
+	return m
+}
+
+func getMessage(c *Conn) *message {
+	m := reqPool.Get().(*message)
+	m.conn = c
+	return m
+}
+
+func putMessage(m *message) {
+	m.buf = m.buf[:bufSize]
+	m.conn = nil
+	m.off = 0
+	reqPool.Put(m)
+}
+
+// a message represents the bytes of a single FUSE message
+type message struct {
+	conn *Conn
+	buf  []byte    // all bytes
+	hdr  *inHeader // header
+	off  int       // offset for reading additional fields
+}
+
+func (m *message) len() uintptr {
+	return uintptr(len(m.buf) - m.off)
+}
+
+func (m *message) data() unsafe.Pointer {
+	var p unsafe.Pointer
+	if m.off < len(m.buf) {
+		p = unsafe.Pointer(&m.buf[m.off])
+	}
+	return p
+}
+
+func (m *message) bytes() []byte {
+	return m.buf[m.off:]
+}
+
+func (m *message) Header() Header {
+	h := m.hdr
+	return Header{
+		Conn: m.conn,
+		ID:   RequestID(h.Unique),
+		Node: NodeID(h.Nodeid),
+		Uid:  h.Uid,
+		Gid:  h.Gid,
+		Pid:  h.Pid,
+
+		msg: m,
+	}
+}
+
+// fileMode returns a Go os.FileMode from a Unix mode.
+func fileMode(unixMode uint32) os.FileMode {
+	mode := os.FileMode(unixMode & 0777)
+	switch unixMode & syscall.S_IFMT {
+	case syscall.S_IFREG:
+		// nothing
+	case syscall.S_IFDIR:
+		mode |= os.ModeDir
+	case syscall.S_IFCHR:
+		mode |= os.ModeCharDevice | os.ModeDevice
+	case syscall.S_IFBLK:
+		mode |= os.ModeDevice
+	case syscall.S_IFIFO:
+		mode |= os.ModeNamedPipe
+	case syscall.S_IFLNK:
+		mode |= os.ModeSymlink
+	case syscall.S_IFSOCK:
+		mode |= os.ModeSocket
+	default:
+		// no idea
+		mode |= os.ModeDevice
+	}
+	if unixMode&syscall.S_ISUID != 0 {
+		mode |= os.ModeSetuid
+	}
+	if unixMode&syscall.S_ISGID != 0 {
+		mode |= os.ModeSetgid
+	}
+	return mode
+}
+
+type noOpcode struct {
+	Opcode uint32
+}
+
+func (m noOpcode) String() string {
+	return fmt.Sprintf("No opcode %v", m.Opcode)
+}
+
+type malformedMessage struct {
+}
+
+func (malformedMessage) String() string {
+	return "malformed message"
+}
+
+// Close closes the FUSE connection.
+func (c *Conn) Close() error {
+	c.wio.Lock()
+	defer c.wio.Unlock()
+	c.rio.Lock()
+	defer c.rio.Unlock()
+	return c.dev.Close()
+}
+
+// caller must hold wio or rio
+func (c *Conn) fd() int {
+	return int(c.dev.Fd())
+}
+
+func (c *Conn) Protocol() Protocol {
+	return c.proto
+}
+
+// ReadRequest returns the next FUSE request from the kernel.
+//
+// Caller must call either Request.Respond or Request.RespondError in
+// a reasonable time. Caller must not retain Request after that call.
+func (c *Conn) ReadRequest() (Request, error) {
+	m := getMessage(c)
+loop:
+	c.rio.RLock()
+	n, err := syscall.Read(c.fd(), m.buf)
+	c.rio.RUnlock()
+	if err == syscall.EINTR {
+		// OSXFUSE sends EINTR to userspace when a request interrupt
+		// completed before it got sent to userspace?
+		goto loop
+	}
+	if err != nil && err != syscall.ENODEV {
+		putMessage(m)
+		return nil, err
+	}
+	if n <= 0 {
+		putMessage(m)
+		return nil, io.EOF
+	}
+	m.buf = m.buf[:n]
+
+	if n < inHeaderSize {
+		putMessage(m)
+		return nil, errors.New("fuse: message too short")
+	}
+
+	// FreeBSD FUSE sends a short length in the header
+	// for FUSE_INIT even though the actual read length is correct.
+	if n == inHeaderSize+initInSize && m.hdr.Opcode == opInit && m.hdr.Len < uint32(n) {
+		m.hdr.Len = uint32(n)
+	}
+
+	// OSXFUSE sometimes sends the wrong m.hdr.Len in a FUSE_WRITE message.
+	if m.hdr.Len < uint32(n) && m.hdr.Len >= uint32(unsafe.Sizeof(writeIn{})) && m.hdr.Opcode == opWrite {
+		m.hdr.Len = uint32(n)
+	}
+
+	if m.hdr.Len != uint32(n) {
+		// prepare error message before returning m to pool
+		err := fmt.Errorf("fuse: read %d opcode %d but expected %d", n, m.hdr.Opcode, m.hdr.Len)
+		putMessage(m)
+		return nil, err
+	}
+
+	m.off = inHeaderSize
+
+	// Convert to data structures.
+	// Do not trust kernel to hand us well-formed data.
+	var req Request
+	switch m.hdr.Opcode {
+	default:
+		Debug(noOpcode{Opcode: m.hdr.Opcode})
+		goto unrecognized
+
+	case opLookup:
+		buf := m.bytes()
+		n := len(buf)
+		if n == 0 || buf[n-1] != '\x00' {
+			goto corrupt
+		}
+		req = &LookupRequest{
+			Header: m.Header(),
+			Name:   string(buf[:n-1]),
+		}
+
+	case opForget:
+		in := (*forgetIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		req = &ForgetRequest{
+			Header: m.Header(),
+			N:      in.Nlookup,
+		}
+
+	case opGetattr:
+		switch {
+		case c.proto.LT(Protocol{7, 9}):
+			req = &GetattrRequest{
+				Header: m.Header(),
+			}
+
+		default:
+			in := (*getattrIn)(m.data())
+			if m.len() < unsafe.Sizeof(*in) {
+				goto corrupt
+			}
+			req = &GetattrRequest{
+				Header: m.Header(),
+				Flags:  GetattrFlags(in.GetattrFlags),
+				Handle: HandleID(in.Fh),
+			}
+		}
+
+	case opSetattr:
+		in := (*setattrIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		req = &SetattrRequest{
+			Header:   m.Header(),
+			Valid:    SetattrValid(in.Valid),
+			Handle:   HandleID(in.Fh),
+			Size:     in.Size,
+			Atime:    time.Unix(int64(in.Atime), int64(in.AtimeNsec)),
+			Mtime:    time.Unix(int64(in.Mtime), int64(in.MtimeNsec)),
+			Mode:     fileMode(in.Mode),
+			Uid:      in.Uid,
+			Gid:      in.Gid,
+			Bkuptime: in.BkupTime(),
+			Chgtime:  in.Chgtime(),
+			Flags:    in.Flags(),
+		}
+
+	case opReadlink:
+		if len(m.bytes()) > 0 {
+			goto corrupt
+		}
+		req = &ReadlinkRequest{
+			Header: m.Header(),
+		}
+
+	case opSymlink:
+		// m.bytes() is "newName\0target\0"
+		names := m.bytes()
+		if len(names) == 0 || names[len(names)-1] != 0 {
+			goto corrupt
+		}
+		i := bytes.IndexByte(names, '\x00')
+		if i < 0 {
+			goto corrupt
+		}
+		newName, target := names[0:i], names[i+1:len(names)-1]
+		req = &SymlinkRequest{
+			Header:  m.Header(),
+			NewName: string(newName),
+			Target:  string(target),
+		}
+
+	case opLink:
+		in := (*linkIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		newName := m.bytes()[unsafe.Sizeof(*in):]
+		if len(newName) < 2 || newName[len(newName)-1] != 0 {
+			goto corrupt
+		}
+		newName = newName[:len(newName)-1]
+		req = &LinkRequest{
+			Header:  m.Header(),
+			OldNode: NodeID(in.Oldnodeid),
+			NewName: string(newName),
+		}
+
+	case opMknod:
+		size := mknodInSize(c.proto)
+		if m.len() < size {
+			goto corrupt
+		}
+		in := (*mknodIn)(m.data())
+		name := m.bytes()[size:]
+		if len(name) < 2 || name[len(name)-1] != '\x00' {
+			goto corrupt
+		}
+		name = name[:len(name)-1]
+		r := &MknodRequest{
+			Header: m.Header(),
+			Mode:   fileMode(in.Mode),
+			Rdev:   in.Rdev,
+			Name:   string(name),
+		}
+		if c.proto.GE(Protocol{7, 12}) {
+			r.Umask = fileMode(in.Umask) & os.ModePerm
+		}
+		req = r
+
+	case opMkdir:
+		size := mkdirInSize(c.proto)
+		if m.len() < size {
+			goto corrupt
+		}
+		in := (*mkdirIn)(m.data())
+		name := m.bytes()[size:]
+		i := bytes.IndexByte(name, '\x00')
+		if i < 0 {
+			goto corrupt
+		}
+		r := &MkdirRequest{
+			Header: m.Header(),
+			Name:   string(name[:i]),
+			// observed on Linux: mkdirIn.Mode & syscall.S_IFMT == 0,
+			// and this causes fileMode to go into it's "no idea"
+			// code branch; enforce type to directory
+			Mode: fileMode((in.Mode &^ syscall.S_IFMT) | syscall.S_IFDIR),
+		}
+		if c.proto.GE(Protocol{7, 12}) {
+			r.Umask = fileMode(in.Umask) & os.ModePerm
+		}
+		req = r
+
+	case opUnlink, opRmdir:
+		buf := m.bytes()
+		n := len(buf)
+		if n == 0 || buf[n-1] != '\x00' {
+			goto corrupt
+		}
+		req = &RemoveRequest{
+			Header: m.Header(),
+			Name:   string(buf[:n-1]),
+			Dir:    m.hdr.Opcode == opRmdir,
+		}
+
+	case opRename:
+		in := (*renameIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		newDirNodeID := NodeID(in.Newdir)
+		oldNew := m.bytes()[unsafe.Sizeof(*in):]
+		// oldNew should be "old\x00new\x00"
+		if len(oldNew) < 4 {
+			goto corrupt
+		}
+		if oldNew[len(oldNew)-1] != '\x00' {
+			goto corrupt
+		}
+		i := bytes.IndexByte(oldNew, '\x00')
+		if i < 0 {
+			goto corrupt
+		}
+		oldName, newName := string(oldNew[:i]), string(oldNew[i+1:len(oldNew)-1])
+		req = &RenameRequest{
+			Header:  m.Header(),
+			NewDir:  newDirNodeID,
+			OldName: oldName,
+			NewName: newName,
+		}
+
+	case opOpendir, opOpen:
+		in := (*openIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		req = &OpenRequest{
+			Header: m.Header(),
+			Dir:    m.hdr.Opcode == opOpendir,
+			Flags:  openFlags(in.Flags),
+		}
+
+	case opRead, opReaddir:
+		in := (*readIn)(m.data())
+		if m.len() < readInSize(c.proto) {
+			goto corrupt
+		}
+		r := &ReadRequest{
+			Header: m.Header(),
+			Dir:    m.hdr.Opcode == opReaddir,
+			Handle: HandleID(in.Fh),
+			Offset: int64(in.Offset),
+			Size:   int(in.Size),
+		}
+		if c.proto.GE(Protocol{7, 9}) {
+			r.Flags = ReadFlags(in.ReadFlags)
+			r.LockOwner = in.LockOwner
+			r.FileFlags = openFlags(in.Flags)
+		}
+		req = r
+
+	case opWrite:
+		in := (*writeIn)(m.data())
+		if m.len() < writeInSize(c.proto) {
+			goto corrupt
+		}
+		r := &WriteRequest{
+			Header: m.Header(),
+			Handle: HandleID(in.Fh),
+			Offset: int64(in.Offset),
+			Flags:  WriteFlags(in.WriteFlags),
+		}
+		if c.proto.GE(Protocol{7, 9}) {
+			r.LockOwner = in.LockOwner
+			r.FileFlags = openFlags(in.Flags)
+		}
+		buf := m.bytes()[writeInSize(c.proto):]
+		if uint32(len(buf)) < in.Size {
+			goto corrupt
+		}
+		r.Data = buf
+		req = r
+
+	case opStatfs:
+		req = &StatfsRequest{
+			Header: m.Header(),
+		}
+
+	case opRelease, opReleasedir:
+		in := (*releaseIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		req = &ReleaseRequest{
+			Header:       m.Header(),
+			Dir:          m.hdr.Opcode == opReleasedir,
+			Handle:       HandleID(in.Fh),
+			Flags:        openFlags(in.Flags),
+			ReleaseFlags: ReleaseFlags(in.ReleaseFlags),
+			LockOwner:    in.LockOwner,
+		}
+
+	case opFsync, opFsyncdir:
+		in := (*fsyncIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		req = &FsyncRequest{
+			Dir:    m.hdr.Opcode == opFsyncdir,
+			Header: m.Header(),
+			Handle: HandleID(in.Fh),
+			Flags:  in.FsyncFlags,
+		}
+
+	case opSetxattr:
+		in := (*setxattrIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		m.off += int(unsafe.Sizeof(*in))
+		name := m.bytes()
+		i := bytes.IndexByte(name, '\x00')
+		if i < 0 {
+			goto corrupt
+		}
+		xattr := name[i+1:]
+		if uint32(len(xattr)) < in.Size {
+			goto corrupt
+		}
+		xattr = xattr[:in.Size]
+		req = &SetxattrRequest{
+			Header:   m.Header(),
+			Flags:    in.Flags,
+			Position: in.position(),
+			Name:     string(name[:i]),
+			Xattr:    xattr,
+		}
+
+	case opGetxattr:
+		in := (*getxattrIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		name := m.bytes()[unsafe.Sizeof(*in):]
+		i := bytes.IndexByte(name, '\x00')
+		if i < 0 {
+			goto corrupt
+		}
+		req = &GetxattrRequest{
+			Header:   m.Header(),
+			Name:     string(name[:i]),
+			Size:     in.Size,
+			Position: in.position(),
+		}
+
+	case opListxattr:
+		in := (*getxattrIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		req = &ListxattrRequest{
+			Header:   m.Header(),
+			Size:     in.Size,
+			Position: in.position(),
+		}
+
+	case opRemovexattr:
+		buf := m.bytes()
+		n := len(buf)
+		if n == 0 || buf[n-1] != '\x00' {
+			goto corrupt
+		}
+		req = &RemovexattrRequest{
+			Header: m.Header(),
+			Name:   string(buf[:n-1]),
+		}
+
+	case opFlush:
+		in := (*flushIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		req = &FlushRequest{
+			Header:    m.Header(),
+			Handle:    HandleID(in.Fh),
+			Flags:     in.FlushFlags,
+			LockOwner: in.LockOwner,
+		}
+
+	case opInit:
+		in := (*initIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		req = &InitRequest{
+			Header:       m.Header(),
+			Kernel:       Protocol{in.Major, in.Minor},
+			MaxReadahead: in.MaxReadahead,
+			Flags:        InitFlags(in.Flags),
+		}
+
+	case opGetlk:
+		panic("opGetlk")
+	case opSetlk:
+		panic("opSetlk")
+	case opSetlkw:
+		panic("opSetlkw")
+
+	case opAccess:
+		in := (*accessIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		req = &AccessRequest{
+			Header: m.Header(),
+			Mask:   in.Mask,
+		}
+
+	case opCreate:
+		size := createInSize(c.proto)
+		if m.len() < size {
+			goto corrupt
+		}
+		in := (*createIn)(m.data())
+		name := m.bytes()[size:]
+		i := bytes.IndexByte(name, '\x00')
+		if i < 0 {
+			goto corrupt
+		}
+		r := &CreateRequest{
+			Header: m.Header(),
+			Flags:  openFlags(in.Flags),
+			Mode:   fileMode(in.Mode),
+			Name:   string(name[:i]),
+		}
+		if c.proto.GE(Protocol{7, 12}) {
+			r.Umask = fileMode(in.Umask) & os.ModePerm
+		}
+		req = r
+
+	case opInterrupt:
+		in := (*interruptIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		req = &InterruptRequest{
+			Header: m.Header(),
+			IntrID: RequestID(in.Unique),
+		}
+
+	case opBmap:
+		panic("opBmap")
+
+	case opDestroy:
+		req = &DestroyRequest{
+			Header: m.Header(),
+		}
+
+	// OS X
+	case opSetvolname:
+		panic("opSetvolname")
+	case opGetxtimes:
+		panic("opGetxtimes")
+	case opExchange:
+		in := (*exchangeIn)(m.data())
+		if m.len() < unsafe.Sizeof(*in) {
+			goto corrupt
+		}
+		oldDirNodeID := NodeID(in.Olddir)
+		newDirNodeID := NodeID(in.Newdir)
+		oldNew := m.bytes()[unsafe.Sizeof(*in):]
+		// oldNew should be "oldname\x00newname\x00"
+		if len(oldNew) < 4 {
+			goto corrupt
+		}
+		if oldNew[len(oldNew)-1] != '\x00' {
+			goto corrupt
+		}
+		i := bytes.IndexByte(oldNew, '\x00')
+		if i < 0 {
+			goto corrupt
+		}
+		oldName, newName := string(oldNew[:i]), string(oldNew[i+1:len(oldNew)-1])
+		req = &ExchangeDataRequest{
+			Header:  m.Header(),
+			OldDir:  oldDirNodeID,
+			NewDir:  newDirNodeID,
+			OldName: oldName,
+			NewName: newName,
+			// TODO options
+		}
+	}
+
+	return req, nil
+
+corrupt:
+	Debug(malformedMessage{})
+	putMessage(m)
+	return nil, fmt.Errorf("fuse: malformed message")
+
+unrecognized:
+	// Unrecognized message.
+	// Assume higher-level code will send a "no idea what you mean" error.
+	h := m.Header()
+	return &h, nil
+}
+
+type bugShortKernelWrite struct {
+	Written int64
+	Length  int64
+	Error   string
+	Stack   string
+}
+
+func (b bugShortKernelWrite) String() string {
+	return fmt.Sprintf("short kernel write: written=%d/%d error=%q stack=\n%s", b.Written, b.Length, b.Error, b.Stack)
+}
+
+type bugKernelWriteError struct {
+	Error string
+	Stack string
+}
+
+func (b bugKernelWriteError) String() string {
+	return fmt.Sprintf("kernel write error: error=%q stack=\n%s", b.Error, b.Stack)
+}
+
+// safe to call even with nil error
+func errorString(err error) string {
+	if err == nil {
+		return ""
+	}
+	return err.Error()
+}
+
+func (c *Conn) writeToKernel(msg []byte) error {
+	out := (*outHeader)(unsafe.Pointer(&msg[0]))
+	out.Len = uint32(len(msg))
+
+	c.wio.RLock()
+	defer c.wio.RUnlock()
+	nn, err := syscall.Write(c.fd(), msg)
+	if err == nil && nn != len(msg) {
+		Debug(bugShortKernelWrite{
+			Written: int64(nn),
+			Length:  int64(len(msg)),
+			Error:   errorString(err),
+			Stack:   stack(),
+		})
+	}
+	return err
+}
+
+func (c *Conn) respond(msg []byte) {
+	if err := c.writeToKernel(msg); err != nil {
+		Debug(bugKernelWriteError{
+			Error: errorString(err),
+			Stack: stack(),
+		})
+	}
+}
+
+type notCachedError struct{}
+
+func (notCachedError) Error() string {
+	return "node not cached"
+}
+
+var _ ErrorNumber = notCachedError{}
+
+func (notCachedError) Errno() Errno {
+	// Behave just like if the original syscall.ENOENT had been passed
+	// straight through.
+	return ENOENT
+}
+
+var (
+	ErrNotCached = notCachedError{}
+)
+
+// sendInvalidate sends an invalidate notification to kernel.
+//
+// A returned ENOENT is translated to a friendlier error.
+func (c *Conn) sendInvalidate(msg []byte) error {
+	switch err := c.writeToKernel(msg); err {
+	case syscall.ENOENT:
+		return ErrNotCached
+	default:
+		return err
+	}
+}
+
+// InvalidateNode invalidates the kernel cache of the attributes and a
+// range of the data of a node.
+//
+// Giving offset 0 and size -1 means all data. To invalidate just the
+// attributes, give offset 0 and size 0.
+//
+// Returns ErrNotCached if the kernel is not currently caching the
+// node.
+func (c *Conn) InvalidateNode(nodeID NodeID, off int64, size int64) error {
+	buf := newBuffer(unsafe.Sizeof(notifyInvalInodeOut{}))
+	h := (*outHeader)(unsafe.Pointer(&buf[0]))
+	// h.Unique is 0
+	h.Error = notifyCodeInvalInode
+	out := (*notifyInvalInodeOut)(buf.alloc(unsafe.Sizeof(notifyInvalInodeOut{})))
+	out.Ino = uint64(nodeID)
+	out.Off = off
+	out.Len = size
+	return c.sendInvalidate(buf)
+}
+
+// InvalidateEntry invalidates the kernel cache of the directory entry
+// identified by parent directory node ID and entry basename.
+//
+// Kernel may or may not cache directory listings. To invalidate
+// those, use InvalidateNode to invalidate all of the data for a
+// directory. (As of 2015-06, Linux FUSE does not cache directory
+// listings.)
+//
+// Returns ErrNotCached if the kernel is not currently caching the
+// node.
+func (c *Conn) InvalidateEntry(parent NodeID, name string) error {
+	const maxUint32 = ^uint32(0)
+	if uint64(len(name)) > uint64(maxUint32) {
+		// very unlikely, but we don't want to silently truncate
+		return syscall.ENAMETOOLONG
+	}
+	buf := newBuffer(unsafe.Sizeof(notifyInvalEntryOut{}) + uintptr(len(name)) + 1)
+	h := (*outHeader)(unsafe.Pointer(&buf[0]))
+	// h.Unique is 0
+	h.Error = notifyCodeInvalEntry
+	out := (*notifyInvalEntryOut)(buf.alloc(unsafe.Sizeof(notifyInvalEntryOut{})))
+	out.Parent = uint64(parent)
+	out.Namelen = uint32(len(name))
+	buf = append(buf, name...)
+	buf = append(buf, '\x00')
+	return c.sendInvalidate(buf)
+}
+
+// An InitRequest is the first request sent on a FUSE file system.
+type InitRequest struct {
+	Header `json:"-"`
+	Kernel Protocol
+	// Maximum readahead in bytes that the kernel plans to use.
+	MaxReadahead uint32
+	Flags        InitFlags
+}
+
+var _ = Request(&InitRequest{})
+
+func (r *InitRequest) String() string {
+	return fmt.Sprintf("Init [%v] %v ra=%d fl=%v", &r.Header, r.Kernel, r.MaxReadahead, r.Flags)
+}
+
+// An InitResponse is the response to an InitRequest.
+type InitResponse struct {
+	Library Protocol
+	// Maximum readahead in bytes that the kernel can use. Ignored if
+	// greater than InitRequest.MaxReadahead.
+	MaxReadahead uint32
+	Flags        InitFlags
+	// Maximum size of a single write operation.
+	// Linux enforces a minimum of 4 KiB.
+	MaxWrite uint32
+}
+
+func (r *InitResponse) String() string {
+	return fmt.Sprintf("Init %v ra=%d fl=%v w=%d", r.Library, r.MaxReadahead, r.Flags, r.MaxWrite)
+}
+
+// Respond replies to the request with the given response.
+func (r *InitRequest) Respond(resp *InitResponse) {
+	buf := newBuffer(unsafe.Sizeof(initOut{}))
+	out := (*initOut)(buf.alloc(unsafe.Sizeof(initOut{})))
+	out.Major = resp.Library.Major
+	out.Minor = resp.Library.Minor
+	out.MaxReadahead = resp.MaxReadahead
+	out.Flags = uint32(resp.Flags)
+	out.MaxWrite = resp.MaxWrite
+
+	// MaxWrite larger than our receive buffer would just lead to
+	// errors on large writes.
+	if out.MaxWrite > maxWrite {
+		out.MaxWrite = maxWrite
+	}
+	r.respond(buf)
+}
+
+// A StatfsRequest requests information about the mounted file system.
+type StatfsRequest struct {
+	Header `json:"-"`
+}
+
+var _ = Request(&StatfsRequest{})
+
+func (r *StatfsRequest) String() string {
+	return fmt.Sprintf("Statfs [%s]", &r.Header)
+}
+
+// Respond replies to the request with the given response.
+func (r *StatfsRequest) Respond(resp *StatfsResponse) {
+	buf := newBuffer(unsafe.Sizeof(statfsOut{}))
+	out := (*statfsOut)(buf.alloc(unsafe.Sizeof(statfsOut{})))
+	out.St = kstatfs{
+		Blocks:  resp.Blocks,
+		Bfree:   resp.Bfree,
+		Bavail:  resp.Bavail,
+		Files:   resp.Files,
+		Ffree:   resp.Ffree,
+		Bsize:   resp.Bsize,
+		Namelen: resp.Namelen,
+		Frsize:  resp.Frsize,
+	}
+	r.respond(buf)
+}
+
+// A StatfsResponse is the response to a StatfsRequest.
+type StatfsResponse struct {
+	Blocks  uint64 // Total data blocks in file system.
+	Bfree   uint64 // Free blocks in file system.
+	Bavail  uint64 // Free blocks in file system if you're not root.
+	Files   uint64 // Total files in file system.
+	Ffree   uint64 // Free files in file system.
+	Bsize   uint32 // Block size
+	Namelen uint32 // Maximum file name length?
+	Frsize  uint32 // Fragment size, smallest addressable data size in the file system.
+}
+
+func (r *StatfsResponse) String() string {
+	return fmt.Sprintf("Statfs blocks=%d/%d/%d files=%d/%d bsize=%d frsize=%d namelen=%d",
+		r.Bavail, r.Bfree, r.Blocks,
+		r.Ffree, r.Files,
+		r.Bsize,
+		r.Frsize,
+		r.Namelen,
+	)
+}
+
+// An AccessRequest asks whether the file can be accessed
+// for the purpose specified by the mask.
+type AccessRequest struct {
+	Header `json:"-"`
+	Mask   uint32
+}
+
+var _ = Request(&AccessRequest{})
+
+func (r *AccessRequest) String() string {
+	return fmt.Sprintf("Access [%s] mask=%#x", &r.Header, r.Mask)
+}
+
+// Respond replies to the request indicating that access is allowed.
+// To deny access, use RespondError.
+func (r *AccessRequest) Respond() {
+	buf := newBuffer(0)
+	r.respond(buf)
+}
+
+// An Attr is the metadata for a single file or directory.
+type Attr struct {
+	Valid time.Duration // how long Attr can be cached
+
+	Inode     uint64      // inode number
+	Size      uint64      // size in bytes
+	Blocks    uint64      // size in 512-byte units
+	Atime     time.Time   // time of last access
+	Mtime     time.Time   // time of last modification
+	Ctime     time.Time   // time of last inode change
+	Crtime    time.Time   // time of creation (OS X only)
+	Mode      os.FileMode // file mode
+	Nlink     uint32      // number of links (usually 1)
+	Uid       uint32      // owner uid
+	Gid       uint32      // group gid
+	Rdev      uint32      // device numbers
+	Flags     uint32      // chflags(2) flags (OS X only)
+	BlockSize uint32      // preferred blocksize for filesystem I/O
+}
+
+func (a Attr) String() string {
+	return fmt.Sprintf("valid=%v ino=%v size=%d mode=%v", a.Valid, a.Inode, a.Size, a.Mode)
+}
+
+func unix(t time.Time) (sec uint64, nsec uint32) {
+	nano := t.UnixNano()
+	sec = uint64(nano / 1e9)
+	nsec = uint32(nano % 1e9)
+	return
+}
+
+func (a *Attr) attr(out *attr, proto Protocol) {
+	out.Ino = a.Inode
+	out.Size = a.Size
+	out.Blocks = a.Blocks
+	out.Atime, out.AtimeNsec = unix(a.Atime)
+	out.Mtime, out.MtimeNsec = unix(a.Mtime)
+	out.Ctime, out.CtimeNsec = unix(a.Ctime)
+	out.SetCrtime(unix(a.Crtime))
+	out.Mode = uint32(a.Mode) & 0777
+	switch {
+	default:
+		out.Mode |= syscall.S_IFREG
+	case a.Mode&os.ModeDir != 0:
+		out.Mode |= syscall.S_IFDIR
+	case a.Mode&os.ModeDevice != 0:
+		if a.Mode&os.ModeCharDevice != 0 {
+			out.Mode |= syscall.S_IFCHR
+		} else {
+			out.Mode |= syscall.S_IFBLK
+		}
+	case a.Mode&os.ModeNamedPipe != 0:
+		out.Mode |= syscall.S_IFIFO
+	case a.Mode&os.ModeSymlink != 0:
+		out.Mode |= syscall.S_IFLNK
+	case a.Mode&os.ModeSocket != 0:
+		out.Mode |= syscall.S_IFSOCK
+	}
+	if a.Mode&os.ModeSetuid != 0 {
+		out.Mode |= syscall.S_ISUID
+	}
+	if a.Mode&os.ModeSetgid != 0 {
+		out.Mode |= syscall.S_ISGID
+	}
+	out.Nlink = a.Nlink
+	out.Uid = a.Uid
+	out.Gid = a.Gid
+	out.Rdev = a.Rdev
+	out.SetFlags(a.Flags)
+	if proto.GE(Protocol{7, 9}) {
+		out.Blksize = a.BlockSize
+	}
+
+	return
+}
+
+// A GetattrRequest asks for the metadata for the file denoted by r.Node.
+type GetattrRequest struct {
+	Header `json:"-"`
+	Flags  GetattrFlags
+	Handle HandleID
+}
+
+var _ = Request(&GetattrRequest{})
+
+func (r *GetattrRequest) String() string {
+	return fmt.Sprintf("Getattr [%s] %v fl=%v", &r.Header, r.Handle, r.Flags)
+}
+
+// Respond replies to the request with the given response.
+func (r *GetattrRequest) Respond(resp *GetattrResponse) {
+	size := attrOutSize(r.Header.Conn.proto)
+	buf := newBuffer(size)
+	out := (*attrOut)(buf.alloc(size))
+	out.AttrValid = uint64(resp.Attr.Valid / time.Second)
+	out.AttrValidNsec = uint32(resp.Attr.Valid % time.Second / time.Nanosecond)
+	resp.Attr.attr(&out.Attr, r.Header.Conn.proto)
+	r.respond(buf)
+}
+
+// A GetattrResponse is the response to a GetattrRequest.
+type GetattrResponse struct {
+	Attr Attr // file attributes
+}
+
+func (r *GetattrResponse) String() string {
+	return fmt.Sprintf("Getattr %v", r.Attr)
+}
+
+// A GetxattrRequest asks for the extended attributes associated with r.Node.
+type GetxattrRequest struct {
+	Header `json:"-"`
+
+	// Maximum size to return.
+	Size uint32
+
+	// Name of the attribute requested.
+	Name string
+
+	// Offset within extended attributes.
+	//
+	// Only valid for OS X, and then only with the resource fork
+	// attribute.
+	Position uint32
+}
+
+var _ = Request(&GetxattrRequest{})
+
+func (r *GetxattrRequest) String() string {
+	return fmt.Sprintf("Getxattr [%s] %q %d @%d", &r.Header, r.Name, r.Size, r.Position)
+}
+
+// Respond replies to the request with the given response.
+func (r *GetxattrRequest) Respond(resp *GetxattrResponse) {
+	if r.Size == 0 {
+		buf := newBuffer(unsafe.Sizeof(getxattrOut{}))
+		out := (*getxattrOut)(buf.alloc(unsafe.Sizeof(getxattrOut{})))
+		out.Size = uint32(len(resp.Xattr))
+		r.respond(buf)
+	} else {
+		buf := newBuffer(uintptr(len(resp.Xattr)))
+		buf = append(buf, resp.Xattr...)
+		r.respond(buf)
+	}
+}
+
+// A GetxattrResponse is the response to a GetxattrRequest.
+type GetxattrResponse struct {
+	Xattr []byte
+}
+
+func (r *GetxattrResponse) String() string {
+	return fmt.Sprintf("Getxattr %x", r.Xattr)
+}
+
+// A ListxattrRequest asks to list the extended attributes associated with r.Node.
+type ListxattrRequest struct {
+	Header   `json:"-"`
+	Size     uint32 // maximum size to return
+	Position uint32 // offset within attribute list
+}
+
+var _ = Request(&ListxattrRequest{})
+
+func (r *ListxattrRequest) String() string {
+	return fmt.Sprintf("Listxattr [%s] %d @%d", &r.Header, r.Size, r.Position)
+}
+
+// Respond replies to the request with the given response.
+func (r *ListxattrRequest) Respond(resp *ListxattrResponse) {
+	if r.Size == 0 {
+		buf := newBuffer(unsafe.Sizeof(getxattrOut{}))
+		out := (*getxattrOut)(buf.alloc(unsafe.Sizeof(getxattrOut{})))
+		out.Size = uint32(len(resp.Xattr))
+		r.respond(buf)
+	} else {
+		buf := newBuffer(uintptr(len(resp.Xattr)))
+		buf = append(buf, resp.Xattr...)
+		r.respond(buf)
+	}
+}
+
+// A ListxattrResponse is the response to a ListxattrRequest.
+type ListxattrResponse struct {
+	Xattr []byte
+}
+
+func (r *ListxattrResponse) String() string {
+	return fmt.Sprintf("Listxattr %x", r.Xattr)
+}
+
+// Append adds an extended attribute name to the response.
+func (r *ListxattrResponse) Append(names ...string) {
+	for _, name := range names {
+		r.Xattr = append(r.Xattr, name...)
+		r.Xattr = append(r.Xattr, '\x00')
+	}
+}
+
+// A RemovexattrRequest asks to remove an extended attribute associated with r.Node.
+type RemovexattrRequest struct {
+	Header `json:"-"`
+	Name   string // name of extended attribute
+}
+
+var _ = Request(&RemovexattrRequest{})
+
+func (r *RemovexattrRequest) String() string {
+	return fmt.Sprintf("Removexattr [%s] %q", &r.Header, r.Name)
+}
+
+// Respond replies to the request, indicating that the attribute was removed.
+func (r *RemovexattrRequest) Respond() {
+	buf := newBuffer(0)
+	r.respond(buf)
+}
+
+// A SetxattrRequest asks to set an extended attribute associated with a file.
+type SetxattrRequest struct {
+	Header `json:"-"`
+
+	// Flags can make the request fail if attribute does/not already
+	// exist. Unfortunately, the constants are platform-specific and
+	// not exposed by Go1.2. Look for XATTR_CREATE, XATTR_REPLACE.
+	//
+	// TODO improve this later
+	//
+	// TODO XATTR_CREATE and exist -> EEXIST
+	//
+	// TODO XATTR_REPLACE and not exist -> ENODATA
+	Flags uint32
+
+	// Offset within extended attributes.
+	//
+	// Only valid for OS X, and then only with the resource fork
+	// attribute.
+	Position uint32
+
+	Name  string
+	Xattr []byte
+}
+
+var _ = Request(&SetxattrRequest{})
+
+func trunc(b []byte, max int) ([]byte, string) {
+	if len(b) > max {
+		return b[:max], "..."
+	}
+	return b, ""
+}
+
+func (r *SetxattrRequest) String() string {
+	xattr, tail := trunc(r.Xattr, 16)
+	return fmt.Sprintf("Setxattr [%s] %q %x%s fl=%v @%#x", &r.Header, r.Name, xattr, tail, r.Flags, r.Position)
+}
+
+// Respond replies to the request, indicating that the extended attribute was set.
+func (r *SetxattrRequest) Respond() {
+	buf := newBuffer(0)
+	r.respond(buf)
+}
+
+// A LookupRequest asks to look up the given name in the directory named by r.Node.
+type LookupRequest struct {
+	Header `json:"-"`
+	Name   string
+}
+
+var _ = Request(&LookupRequest{})
+
+func (r *LookupRequest) String() string {
+	return fmt.Sprintf("Lookup [%s] %q", &r.Header, r.Name)
+}
+
+// Respond replies to the request with the given response.
+func (r *LookupRequest) Respond(resp *LookupResponse) {
+	size := entryOutSize(r.Header.Conn.proto)
+	buf := newBuffer(size)
+	out := (*entryOut)(buf.alloc(size))
+	out.Nodeid = uint64(resp.Node)
+	out.Generation = resp.Generation
+	out.EntryValid = uint64(resp.EntryValid / time.Second)
+	out.EntryValidNsec = uint32(resp.EntryValid % time.Second / time.Nanosecond)
+	out.AttrValid = uint64(resp.Attr.Valid / time.Second)
+	out.AttrValidNsec = uint32(resp.Attr.Valid % time.Second / time.Nanosecond)
+	resp.Attr.attr(&out.Attr, r.Header.Conn.proto)
+	r.respond(buf)
+}
+
+// A LookupResponse is the response to a LookupRequest.
+type LookupResponse struct {
+	Node       NodeID
+	Generation uint64
+	EntryValid time.Duration
+	Attr       Attr
+}
+
+func (r *LookupResponse) string() string {
+	return fmt.Sprintf("%v gen=%d valid=%v attr={%v}", r.Node, r.Generation, r.EntryValid, r.Attr)
+}
+
+func (r *LookupResponse) String() string {
+	return fmt.Sprintf("Lookup %s", r.string())
+}
+
+// An OpenRequest asks to open a file or directory
+type OpenRequest struct {
+	Header `json:"-"`
+	Dir    bool // is this Opendir?
+	Flags  OpenFlags
+}
+
+var _ = Request(&OpenRequest{})
+
+func (r *OpenRequest) String() string {
+	return fmt.Sprintf("Open [%s] dir=%v fl=%v", &r.Header, r.Dir, r.Flags)
+}
+
+// Respond replies to the request with the given response.
+func (r *OpenRequest) Respond(resp *OpenResponse) {
+	buf := newBuffer(unsafe.Sizeof(openOut{}))
+	out := (*openOut)(buf.alloc(unsafe.Sizeof(openOut{})))
+	out.Fh = uint64(resp.Handle)
+	out.OpenFlags = uint32(resp.Flags)
+	r.respond(buf)
+}
+
+// A OpenResponse is the response to a OpenRequest.
+type OpenResponse struct {
+	Handle HandleID
+	Flags  OpenResponseFlags
+}
+
+func (r *OpenResponse) string() string {
+	return fmt.Sprintf("%v fl=%v", r.Handle, r.Flags)
+}
+
+func (r *OpenResponse) String() string {
+	return fmt.Sprintf("Open %s", r.string())
+}
+
+// A CreateRequest asks to create and open a file (not a directory).
+type CreateRequest struct {
+	Header `json:"-"`
+	Name   string
+	Flags  OpenFlags
+	Mode   os.FileMode
+	// Umask of the request. Not supported on OS X.
+	Umask os.FileMode
+}
+
+var _ = Request(&CreateRequest{})
+
+func (r *CreateRequest) String() string {
+	return fmt.Sprintf("Create [%s] %q fl=%v mode=%v umask=%v", &r.Header, r.Name, r.Flags, r.Mode, r.Umask)
+}
+
+// Respond replies to the request with the given response.
+func (r *CreateRequest) Respond(resp *CreateResponse) {
+	eSize := entryOutSize(r.Header.Conn.proto)
+	buf := newBuffer(eSize + unsafe.Sizeof(openOut{}))
+
+	e := (*entryOut)(buf.alloc(eSize))
+	e.Nodeid = uint64(resp.Node)
+	e.Generation = resp.Generation
+	e.EntryValid = uint64(resp.EntryValid / time.Second)
+	e.EntryValidNsec = uint32(resp.EntryValid % time.Second / time.Nanosecond)
+	e.AttrValid = uint64(resp.Attr.Valid / time.Second)
+	e.AttrValidNsec = uint32(resp.Attr.Valid % time.Second / time.Nanosecond)
+	resp.Attr.attr(&e.Attr, r.Header.Conn.proto)
+
+	o := (*openOut)(buf.alloc(unsafe.Sizeof(openOut{})))
+	o.Fh = uint64(resp.Handle)
+	o.OpenFlags = uint32(resp.Flags)
+
+	r.respond(buf)
+}
+
+// A CreateResponse is the response to a CreateRequest.
+// It describes the created node and opened handle.
+type CreateResponse struct {
+	LookupResponse
+	OpenResponse
+}
+
+func (r *CreateResponse) String() string {
+	return fmt.Sprintf("Create {%s} {%s}", r.LookupResponse.string(), r.OpenResponse.string())
+}
+
+// A MkdirRequest asks to create (but not open) a directory.
+type MkdirRequest struct {
+	Header `json:"-"`
+	Name   string
+	Mode   os.FileMode
+	// Umask of the request. Not supported on OS X.
+	Umask os.FileMode
+}
+
+var _ = Request(&MkdirRequest{})
+
+func (r *MkdirRequest) String() string {
+	return fmt.Sprintf("Mkdir [%s] %q mode=%v umask=%v", &r.Header, r.Name, r.Mode, r.Umask)
+}
+
+// Respond replies to the request with the given response.
+func (r *MkdirRequest) Respond(resp *MkdirResponse) {
+	size := entryOutSize(r.Header.Conn.proto)
+	buf := newBuffer(size)
+	out := (*entryOut)(buf.alloc(size))
+	out.Nodeid = uint64(resp.Node)
+	out.Generation = resp.Generation
+	out.EntryValid = uint64(resp.EntryValid / time.Second)
+	out.EntryValidNsec = uint32(resp.EntryValid % time.Second / time.Nanosecond)
+	out.AttrValid = uint64(resp.Attr.Valid / time.Second)
+	out.AttrValidNsec = uint32(resp.Attr.Valid % time.Second / time.Nanosecond)
+	resp.Attr.attr(&out.Attr, r.Header.Conn.proto)
+	r.respond(buf)
+}
+
+// A MkdirResponse is the response to a MkdirRequest.
+type MkdirResponse struct {
+	LookupResponse
+}
+
+func (r *MkdirResponse) String() string {
+	return fmt.Sprintf("Mkdir %v", r.LookupResponse.string())
+}
+
+// A ReadRequest asks to read from an open file.
+type ReadRequest struct {
+	Header    `json:"-"`
+	Dir       bool // is this Readdir?
+	Handle    HandleID
+	Offset    int64
+	Size      int
+	Flags     ReadFlags
+	LockOwner uint64
+	FileFlags OpenFlags
+}
+
+var _ = Request(&ReadRequest{})
+
+func (r *ReadRequest) String() string {
+	return fmt.Sprintf("Read [%s] %v %d @%#x dir=%v fl=%v lock=%d ffl=%v", &r.Header, r.Handle, r.Size, r.Offset, r.Dir, r.Flags, r.LockOwner, r.FileFlags)
+}
+
+// Respond replies to the request with the given response.
+func (r *ReadRequest) Respond(resp *ReadResponse) {
+	buf := newBuffer(uintptr(len(resp.Data)))
+	buf = append(buf, resp.Data...)
+	r.respond(buf)
+}
+
+// A ReadResponse is the response to a ReadRequest.
+type ReadResponse struct {
+	Data []byte
+}
+
+func (r *ReadResponse) String() string {
+	return fmt.Sprintf("Read %d", len(r.Data))
+}
+
+type jsonReadResponse struct {
+	Len uint64
+}
+
+func (r *ReadResponse) MarshalJSON() ([]byte, error) {
+	j := jsonReadResponse{
+		Len: uint64(len(r.Data)),
+	}
+	return json.Marshal(j)
+}
+
+// A ReleaseRequest asks to release (close) an open file handle.
+type ReleaseRequest struct {
+	Header       `json:"-"`
+	Dir          bool // is this Releasedir?
+	Handle       HandleID
+	Flags        OpenFlags // flags from OpenRequest
+	ReleaseFlags ReleaseFlags
+	LockOwner    uint32
+}
+
+var _ = Request(&ReleaseRequest{})
+
+func (r *ReleaseRequest) String() string {
+	return fmt.Sprintf("Release [%s] %v fl=%v rfl=%v owner=%#x", &r.Header, r.Handle, r.Flags, r.ReleaseFlags, r.LockOwner)
+}
+
+// Respond replies to the request, indicating that the handle has been released.
+func (r *ReleaseRequest) Respond() {
+	buf := newBuffer(0)
+	r.respond(buf)
+}
+
+// A DestroyRequest is sent by the kernel when unmounting the file system.
+// No more requests will be received after this one, but it should still be
+// responded to.
+type DestroyRequest struct {
+	Header `json:"-"`
+}
+
+var _ = Request(&DestroyRequest{})
+
+func (r *DestroyRequest) String() string {
+	return fmt.Sprintf("Destroy [%s]", &r.Header)
+}
+
+// Respond replies to the request.
+func (r *DestroyRequest) Respond() {
+	buf := newBuffer(0)
+	r.respond(buf)
+}
+
+// A ForgetRequest is sent by the kernel when forgetting about r.Node
+// as returned by r.N lookup requests.
+type ForgetRequest struct {
+	Header `json:"-"`
+	N      uint64
+}
+
+var _ = Request(&ForgetRequest{})
+
+func (r *ForgetRequest) String() string {
+	return fmt.Sprintf("Forget [%s] %d", &r.Header, r.N)
+}
+
+// Respond replies to the request, indicating that the forgetfulness has been recorded.
+func (r *ForgetRequest) Respond() {
+	// Don't reply to forget messages.
+	r.noResponse()
+}
+
+// A Dirent represents a single directory entry.
+type Dirent struct {
+	// Inode this entry names.
+	Inode uint64
+
+	// Type of the entry, for example DT_File.
+	//
+	// Setting this is optional. The zero value (DT_Unknown) means
+	// callers will just need to do a Getattr when the type is
+	// needed. Providing a type can speed up operations
+	// significantly.
+	Type DirentType
+
+	// Name of the entry
+	Name string
+}
+
+// Type of an entry in a directory listing.
+type DirentType uint32
+
+const (
+	// These don't quite match os.FileMode; especially there's an
+	// explicit unknown, instead of zero value meaning file. They
+	// are also not quite syscall.DT_*; nothing says the FUSE
+	// protocol follows those, and even if they were, we don't
+	// want each fs to fiddle with syscall.
+
+	// The shift by 12 is hardcoded in the FUSE userspace
+	// low-level C library, so it's safe here.
+
+	DT_Unknown DirentType = 0
+	DT_Socket  DirentType = syscall.S_IFSOCK >> 12
+	DT_Link    DirentType = syscall.S_IFLNK >> 12
+	DT_File    DirentType = syscall.S_IFREG >> 12
+	DT_Block   DirentType = syscall.S_IFBLK >> 12
+	DT_Dir     DirentType = syscall.S_IFDIR >> 12
+	DT_Char    DirentType = syscall.S_IFCHR >> 12
+	DT_FIFO    DirentType = syscall.S_IFIFO >> 12
+)
+
+func (t DirentType) String() string {
+	switch t {
+	case DT_Unknown:
+		return "unknown"
+	case DT_Socket:
+		return "socket"
+	case DT_Link:
+		return "link"
+	case DT_File:
+		return "file"
+	case DT_Block:
+		return "block"
+	case DT_Dir:
+		return "dir"
+	case DT_Char:
+		return "char"
+	case DT_FIFO:
+		return "fifo"
+	}
+	return "invalid"
+}
+
+// AppendDirent appends the encoded form of a directory entry to data
+// and returns the resulting slice.
+func AppendDirent(data []byte, dir Dirent) []byte {
+	de := dirent{
+		Ino:     dir.Inode,
+		Namelen: uint32(len(dir.Name)),
+		Type:    uint32(dir.Type),
+	}
+	de.Off = uint64(len(data) + direntSize + (len(dir.Name)+7)&^7)
+	data = append(data, (*[direntSize]byte)(unsafe.Pointer(&de))[:]...)
+	data = append(data, dir.Name...)
+	n := direntSize + uintptr(len(dir.Name))
+	if n%8 != 0 {
+		var pad [8]byte
+		data = append(data, pad[:8-n%8]...)
+	}
+	return data
+}
+
+// A WriteRequest asks to write to an open file.
+type WriteRequest struct {
+	Header
+	Handle    HandleID
+	Offset    int64
+	Data      []byte
+	Flags     WriteFlags
+	LockOwner uint64
+	FileFlags OpenFlags
+}
+
+var _ = Request(&WriteRequest{})
+
+func (r *WriteRequest) String() string {
+	return fmt.Sprintf("Write [%s] %v %d @%d fl=%v lock=%d ffl=%v", &r.Header, r.Handle, len(r.Data), r.Offset, r.Flags, r.LockOwner, r.FileFlags)
+}
+
+type jsonWriteRequest struct {
+	Handle HandleID
+	Offset int64
+	Len    uint64
+	Flags  WriteFlags
+}
+
+func (r *WriteRequest) MarshalJSON() ([]byte, error) {
+	j := jsonWriteRequest{
+		Handle: r.Handle,
+		Offset: r.Offset,
+		Len:    uint64(len(r.Data)),
+		Flags:  r.Flags,
+	}
+	return json.Marshal(j)
+}
+
+// Respond replies to the request with the given response.
+func (r *WriteRequest) Respond(resp *WriteResponse) {
+	buf := newBuffer(unsafe.Sizeof(writeOut{}))
+	out := (*writeOut)(buf.alloc(unsafe.Sizeof(writeOut{})))
+	out.Size = uint32(resp.Size)
+	r.respond(buf)
+}
+
+// A WriteResponse replies to a write indicating how many bytes were written.
+type WriteResponse struct {
+	Size int
+}
+
+func (r *WriteResponse) String() string {
+	return fmt.Sprintf("Write %d", r.Size)
+}
+
+// A SetattrRequest asks to change one or more attributes associated with a file,
+// as indicated by Valid.
+type SetattrRequest struct {
+	Header `json:"-"`
+	Valid  SetattrValid
+	Handle HandleID
+	Size   uint64
+	Atime  time.Time
+	Mtime  time.Time
+	Mode   os.FileMode
+	Uid    uint32
+	Gid    uint32
+
+	// OS X only
+	Bkuptime time.Time
+	Chgtime  time.Time
+	Crtime   time.Time
+	Flags    uint32 // see chflags(2)
+}
+
+var _ = Request(&SetattrRequest{})
+
+func (r *SetattrRequest) String() string {
+	var buf bytes.Buffer
+	fmt.Fprintf(&buf, "Setattr [%s]", &r.Header)
+	if r.Valid.Mode() {
+		fmt.Fprintf(&buf, " mode=%v", r.Mode)
+	}
+	if r.Valid.Uid() {
+		fmt.Fprintf(&buf, " uid=%d", r.Uid)
+	}
+	if r.Valid.Gid() {
+		fmt.Fprintf(&buf, " gid=%d", r.Gid)
+	}
+	if r.Valid.Size() {
+		fmt.Fprintf(&buf, " size=%d", r.Size)
+	}
+	if r.Valid.Atime() {
+		fmt.Fprintf(&buf, " atime=%v", r.Atime)
+	}
+	if r.Valid.AtimeNow() {
+		fmt.Fprintf(&buf, " atime=now")
+	}
+	if r.Valid.Mtime() {
+		fmt.Fprintf(&buf, " mtime=%v", r.Mtime)
+	}
+	if r.Valid.MtimeNow() {
+		fmt.Fprintf(&buf, " mtime=now")
+	}
+	if r.Valid.Handle() {
+		fmt.Fprintf(&buf, " handle=%v", r.Handle)
+	} else {
+		fmt.Fprintf(&buf, " handle=INVALID-%v", r.Handle)
+	}
+	if r.Valid.LockOwner() {
+		fmt.Fprintf(&buf, " lockowner")
+	}
+	if r.Valid.Crtime() {
+		fmt.Fprintf(&buf, " crtime=%v", r.Crtime)
+	}
+	if r.Valid.Chgtime() {
+		fmt.Fprintf(&buf, " chgtime=%v", r.Chgtime)
+	}
+	if r.Valid.Bkuptime() {
+		fmt.Fprintf(&buf, " bkuptime=%v", r.Bkuptime)
+	}
+	if r.Valid.Flags() {
+		fmt.Fprintf(&buf, " flags=%v", r.Flags)
+	}
+	return buf.String()
+}
+
+// Respond replies to the request with the given response,
+// giving the updated attributes.
+func (r *SetattrRequest) Respond(resp *SetattrResponse) {
+	size := attrOutSize(r.Header.Conn.proto)
+	buf := newBuffer(size)
+	out := (*attrOut)(buf.alloc(size))
+	out.AttrValid = uint64(resp.Attr.Valid / time.Second)
+	out.AttrValidNsec = uint32(resp.Attr.Valid % time.Second / time.Nanosecond)
+	resp.Attr.attr(&out.Attr, r.Header.Conn.proto)
+	r.respond(buf)
+}
+
+// A SetattrResponse is the response to a SetattrRequest.
+type SetattrResponse struct {
+	Attr Attr // file attributes
+}
+
+func (r *SetattrResponse) String() string {
+	return fmt.Sprintf("Setattr %v", r.Attr)
+}
+
+// A FlushRequest asks for the current state of an open file to be flushed
+// to storage, as when a file descriptor is being closed.  A single opened Handle
+// may receive multiple FlushRequests over its lifetime.
+type FlushRequest struct {
+	Header    `json:"-"`
+	Handle    HandleID
+	Flags     uint32
+	LockOwner uint64
+}
+
+var _ = Request(&FlushRequest{})
+
+func (r *FlushRequest) String() string {
+	return fmt.Sprintf("Flush [%s] %v fl=%#x lk=%#x", &r.Header, r.Handle, r.Flags, r.LockOwner)
+}
+
+// Respond replies to the request, indicating that the flush succeeded.
+func (r *FlushRequest) Respond() {
+	buf := newBuffer(0)
+	r.respond(buf)
+}
+
+// A RemoveRequest asks to remove a file or directory from the
+// directory r.Node.
+type RemoveRequest struct {
+	Header `json:"-"`
+	Name   string // name of the entry to remove
+	Dir    bool   // is this rmdir?
+}
+
+var _ = Request(&RemoveRequest{})
+
+func (r *RemoveRequest) String() string {
+	return fmt.Sprintf("Remove [%s] %q dir=%v", &r.Header, r.Name, r.Dir)
+}
+
+// Respond replies to the request, indicating that the file was removed.
+func (r *RemoveRequest) Respond() {
+	buf := newBuffer(0)
+	r.respond(buf)
+}
+
+// A SymlinkRequest is a request to create a symlink making NewName point to Target.
+type SymlinkRequest struct {
+	Header          `json:"-"`
+	NewName, Target string
+}
+
+var _ = Request(&SymlinkRequest{})
+
+func (r *SymlinkRequest) String() string {
+	return fmt.Sprintf("Symlink [%s] from %q to target %q", &r.Header, r.NewName, r.Target)
+}
+
+// Respond replies to the request, indicating that the symlink was created.
+func (r *SymlinkRequest) Respond(resp *SymlinkResponse) {
+	size := entryOutSize(r.Header.Conn.proto)
+	buf := newBuffer(size)
+	out := (*entryOut)(buf.alloc(size))
+	out.Nodeid = uint64(resp.Node)
+	out.Generation = resp.Generation
+	out.EntryValid = uint64(resp.EntryValid / time.Second)
+	out.EntryValidNsec = uint32(resp.EntryValid % time.Second / time.Nanosecond)
+	out.AttrValid = uint64(resp.Attr.Valid / time.Second)
+	out.AttrValidNsec = uint32(resp.Attr.Valid % time.Second / time.Nanosecond)
+	resp.Attr.attr(&out.Attr, r.Header.Conn.proto)
+	r.respond(buf)
+}
+
+// A SymlinkResponse is the response to a SymlinkRequest.
+type SymlinkResponse struct {
+	LookupResponse
+}
+
+func (r *SymlinkResponse) String() string {
+	return fmt.Sprintf("Symlink %v", r.LookupResponse.string())
+}
+
+// A ReadlinkRequest is a request to read a symlink's target.
+type ReadlinkRequest struct {
+	Header `json:"-"`
+}
+
+var _ = Request(&ReadlinkRequest{})
+
+func (r *ReadlinkRequest) String() string {
+	return fmt.Sprintf("Readlink [%s]", &r.Header)
+}
+
+func (r *ReadlinkRequest) Respond(target string) {
+	buf := newBuffer(uintptr(len(target)))
+	buf = append(buf, target...)
+	r.respond(buf)
+}
+
+// A LinkRequest is a request to create a hard link.
+type LinkRequest struct {
+	Header  `json:"-"`
+	OldNode NodeID
+	NewName string
+}
+
+var _ = Request(&LinkRequest{})
+
+func (r *LinkRequest) String() string {
+	return fmt.Sprintf("Link [%s] node %d to %q", &r.Header, r.OldNode, r.NewName)
+}
+
+func (r *LinkRequest) Respond(resp *LookupResponse) {
+	size := entryOutSize(r.Header.Conn.proto)
+	buf := newBuffer(size)
+	out := (*entryOut)(buf.alloc(size))
+	out.Nodeid = uint64(resp.Node)
+	out.Generation = resp.Generation
+	out.EntryValid = uint64(resp.EntryValid / time.Second)
+	out.EntryValidNsec = uint32(resp.EntryValid % time.Second / time.Nanosecond)
+	out.AttrValid = uint64(resp.Attr.Valid / time.Second)
+	out.AttrValidNsec = uint32(resp.Attr.Valid % time.Second / time.Nanosecond)
+	resp.Attr.attr(&out.Attr, r.Header.Conn.proto)
+	r.respond(buf)
+}
+
+// A RenameRequest is a request to rename a file.
+type RenameRequest struct {
+	Header           `json:"-"`
+	NewDir           NodeID
+	OldName, NewName string
+}
+
+var _ = Request(&RenameRequest{})
+
+func (r *RenameRequest) String() string {
+	return fmt.Sprintf("Rename [%s] from %q to dirnode %v %q", &r.Header, r.OldName, r.NewDir, r.NewName)
+}
+
+func (r *RenameRequest) Respond() {
+	buf := newBuffer(0)
+	r.respond(buf)
+}
+
+type MknodRequest struct {
+	Header `json:"-"`
+	Name   string
+	Mode   os.FileMode
+	Rdev   uint32
+	// Umask of the request. Not supported on OS X.
+	Umask os.FileMode
+}
+
+var _ = Request(&MknodRequest{})
+
+func (r *MknodRequest) String() string {
+	return fmt.Sprintf("Mknod [%s] Name %q mode=%v umask=%v rdev=%d", &r.Header, r.Name, r.Mode, r.Umask, r.Rdev)
+}
+
+func (r *MknodRequest) Respond(resp *LookupResponse) {
+	size := entryOutSize(r.Header.Conn.proto)
+	buf := newBuffer(size)
+	out := (*entryOut)(buf.alloc(size))
+	out.Nodeid = uint64(resp.Node)
+	out.Generation = resp.Generation
+	out.EntryValid = uint64(resp.EntryValid / time.Second)
+	out.EntryValidNsec = uint32(resp.EntryValid % time.Second / time.Nanosecond)
+	out.AttrValid = uint64(resp.Attr.Valid / time.Second)
+	out.AttrValidNsec = uint32(resp.Attr.Valid % time.Second / time.Nanosecond)
+	resp.Attr.attr(&out.Attr, r.Header.Conn.proto)
+	r.respond(buf)
+}
+
+type FsyncRequest struct {
+	Header `json:"-"`
+	Handle HandleID
+	// TODO bit 1 is datasync, not well documented upstream
+	Flags uint32
+	Dir   bool
+}
+
+var _ = Request(&FsyncRequest{})
+
+func (r *FsyncRequest) String() string {
+	return fmt.Sprintf("Fsync [%s] Handle %v Flags %v", &r.Header, r.Handle, r.Flags)
+}
+
+func (r *FsyncRequest) Respond() {
+	buf := newBuffer(0)
+	r.respond(buf)
+}
+
+// An InterruptRequest is a request to interrupt another pending request. The
+// response to that request should return an error status of EINTR.
+type InterruptRequest struct {
+	Header `json:"-"`
+	IntrID RequestID // ID of the request to be interrupt.
+}
+
+var _ = Request(&InterruptRequest{})
+
+func (r *InterruptRequest) Respond() {
+	// nothing to do here
+	r.noResponse()
+}
+
+func (r *InterruptRequest) String() string {
+	return fmt.Sprintf("Interrupt [%s] ID %v", &r.Header, r.IntrID)
+}
+
+// An ExchangeDataRequest is a request to exchange the contents of two
+// files, while leaving most metadata untouched.
+//
+// This request comes from OS X exchangedata(2) and represents its
+// specific semantics. Crucially, it is very different from Linux
+// renameat(2) RENAME_EXCHANGE.
+//
+// https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man2/exchangedata.2.html
+type ExchangeDataRequest struct {
+	Header           `json:"-"`
+	OldDir, NewDir   NodeID
+	OldName, NewName string
+	// TODO options
+}
+
+var _ = Request(&ExchangeDataRequest{})
+
+func (r *ExchangeDataRequest) String() string {
+	// TODO options
+	return fmt.Sprintf("ExchangeData [%s] %v %q and %v %q", &r.Header, r.OldDir, r.OldName, r.NewDir, r.NewName)
+}
+
+func (r *ExchangeDataRequest) Respond() {
+	buf := newBuffer(0)
+	r.respond(buf)
+}
diff --git a/vendor/bazil.org/fuse/fuse_darwin.go b/vendor/bazil.org/fuse/fuse_darwin.go
new file mode 100644
index 000000000..b58dca97d
--- /dev/null
+++ b/vendor/bazil.org/fuse/fuse_darwin.go
@@ -0,0 +1,9 @@
+package fuse
+
+// Maximum file write size we are prepared to receive from the kernel.
+//
+// This value has to be >=16MB or OSXFUSE (3.4.0 observed) will
+// forcibly close the /dev/fuse file descriptor on a Setxattr with a
+// 16MB value. See TestSetxattr16MB and
+// https://github.com/bazil/fuse/issues/42
+const maxWrite = 16 * 1024 * 1024
diff --git a/vendor/bazil.org/fuse/fuse_freebsd.go b/vendor/bazil.org/fuse/fuse_freebsd.go
new file mode 100644
index 000000000..4aa83a0d4
--- /dev/null
+++ b/vendor/bazil.org/fuse/fuse_freebsd.go
@@ -0,0 +1,6 @@
+package fuse
+
+// Maximum file write size we are prepared to receive from the kernel.
+//
+// This number is just a guess.
+const maxWrite = 128 * 1024
diff --git a/vendor/bazil.org/fuse/fuse_kernel.go b/vendor/bazil.org/fuse/fuse_kernel.go
new file mode 100644
index 000000000..87c5ca1dc
--- /dev/null
+++ b/vendor/bazil.org/fuse/fuse_kernel.go
@@ -0,0 +1,774 @@
+// See the file LICENSE for copyright and licensing information.
+
+// Derived from FUSE's fuse_kernel.h, which carries this notice:
+/*
+   This file defines the kernel interface of FUSE
+   Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
+
+
+   This -- and only this -- header file may also be distributed under
+   the terms of the BSD Licence as follows:
+
+   Copyright (C) 2001-2007 Miklos Szeredi. All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+   1. Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+   2. Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+   THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+   ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+   ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+   OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+   SUCH DAMAGE.
+*/
+
+package fuse
+
+import (
+	"fmt"
+	"syscall"
+	"unsafe"
+)
+
+// The FUSE version implemented by the package.
+const (
+	protoVersionMinMajor = 7
+	protoVersionMinMinor = 8
+	protoVersionMaxMajor = 7
+	protoVersionMaxMinor = 12
+)
+
+const (
+	rootID = 1
+)
+
+type kstatfs struct {
+	Blocks  uint64
+	Bfree   uint64
+	Bavail  uint64
+	Files   uint64
+	Ffree   uint64
+	Bsize   uint32
+	Namelen uint32
+	Frsize  uint32
+	_       uint32
+	Spare   [6]uint32
+}
+
+type fileLock struct {
+	Start uint64
+	End   uint64
+	Type  uint32
+	Pid   uint32
+}
+
+// GetattrFlags are bit flags that can be seen in GetattrRequest.
+type GetattrFlags uint32
+
+const (
+	// Indicates the handle is valid.
+	GetattrFh GetattrFlags = 1 << 0
+)
+
+var getattrFlagsNames = []flagName{
+	{uint32(GetattrFh), "GetattrFh"},
+}
+
+func (fl GetattrFlags) String() string {
+	return flagString(uint32(fl), getattrFlagsNames)
+}
+
+// The SetattrValid are bit flags describing which fields in the SetattrRequest
+// are included in the change.
+type SetattrValid uint32
+
+const (
+	SetattrMode   SetattrValid = 1 << 0
+	SetattrUid    SetattrValid = 1 << 1
+	SetattrGid    SetattrValid = 1 << 2
+	SetattrSize   SetattrValid = 1 << 3
+	SetattrAtime  SetattrValid = 1 << 4
+	SetattrMtime  SetattrValid = 1 << 5
+	SetattrHandle SetattrValid = 1 << 6
+
+	// Linux only(?)
+	SetattrAtimeNow  SetattrValid = 1 << 7
+	SetattrMtimeNow  SetattrValid = 1 << 8
+	SetattrLockOwner SetattrValid = 1 << 9 // http://www.mail-archive.com/git-commits-head@vger.kernel.org/msg27852.html
+
+	// OS X only
+	SetattrCrtime   SetattrValid = 1 << 28
+	SetattrChgtime  SetattrValid = 1 << 29
+	SetattrBkuptime SetattrValid = 1 << 30
+	SetattrFlags    SetattrValid = 1 << 31
+)
+
+func (fl SetattrValid) Mode() bool      { return fl&SetattrMode != 0 }
+func (fl SetattrValid) Uid() bool       { return fl&SetattrUid != 0 }
+func (fl SetattrValid) Gid() bool       { return fl&SetattrGid != 0 }
+func (fl SetattrValid) Size() bool      { return fl&SetattrSize != 0 }
+func (fl SetattrValid) Atime() bool     { return fl&SetattrAtime != 0 }
+func (fl SetattrValid) Mtime() bool     { return fl&SetattrMtime != 0 }
+func (fl SetattrValid) Handle() bool    { return fl&SetattrHandle != 0 }
+func (fl SetattrValid) AtimeNow() bool  { return fl&SetattrAtimeNow != 0 }
+func (fl SetattrValid) MtimeNow() bool  { return fl&SetattrMtimeNow != 0 }
+func (fl SetattrValid) LockOwner() bool { return fl&SetattrLockOwner != 0 }
+func (fl SetattrValid) Crtime() bool    { return fl&SetattrCrtime != 0 }
+func (fl SetattrValid) Chgtime() bool   { return fl&SetattrChgtime != 0 }
+func (fl SetattrValid) Bkuptime() bool  { return fl&SetattrBkuptime != 0 }
+func (fl SetattrValid) Flags() bool     { return fl&SetattrFlags != 0 }
+
+func (fl SetattrValid) String() string {
+	return flagString(uint32(fl), setattrValidNames)
+}
+
+var setattrValidNames = []flagName{
+	{uint32(SetattrMode), "SetattrMode"},
+	{uint32(SetattrUid), "SetattrUid"},
+	{uint32(SetattrGid), "SetattrGid"},
+	{uint32(SetattrSize), "SetattrSize"},
+	{uint32(SetattrAtime), "SetattrAtime"},
+	{uint32(SetattrMtime), "SetattrMtime"},
+	{uint32(SetattrHandle), "SetattrHandle"},
+	{uint32(SetattrAtimeNow), "SetattrAtimeNow"},
+	{uint32(SetattrMtimeNow), "SetattrMtimeNow"},
+	{uint32(SetattrLockOwner), "SetattrLockOwner"},
+	{uint32(SetattrCrtime), "SetattrCrtime"},
+	{uint32(SetattrChgtime), "SetattrChgtime"},
+	{uint32(SetattrBkuptime), "SetattrBkuptime"},
+	{uint32(SetattrFlags), "SetattrFlags"},
+}
+
+// Flags that can be seen in OpenRequest.Flags.
+const (
+	// Access modes. These are not 1-bit flags, but alternatives where
+	// only one can be chosen. See the IsReadOnly etc convenience
+	// methods.
+	OpenReadOnly  OpenFlags = syscall.O_RDONLY
+	OpenWriteOnly OpenFlags = syscall.O_WRONLY
+	OpenReadWrite OpenFlags = syscall.O_RDWR
+
+	// File was opened in append-only mode, all writes will go to end
+	// of file. OS X does not provide this information.
+	OpenAppend    OpenFlags = syscall.O_APPEND
+	OpenCreate    OpenFlags = syscall.O_CREAT
+	OpenDirectory OpenFlags = syscall.O_DIRECTORY
+	OpenExclusive OpenFlags = syscall.O_EXCL
+	OpenNonblock  OpenFlags = syscall.O_NONBLOCK
+	OpenSync      OpenFlags = syscall.O_SYNC
+	OpenTruncate  OpenFlags = syscall.O_TRUNC
+)
+
+// OpenAccessModeMask is a bitmask that separates the access mode
+// from the other flags in OpenFlags.
+const OpenAccessModeMask OpenFlags = syscall.O_ACCMODE
+
+// OpenFlags are the O_FOO flags passed to open/create/etc calls. For
+// example, os.O_WRONLY | os.O_APPEND.
+type OpenFlags uint32
+
+func (fl OpenFlags) String() string {
+	// O_RDONLY, O_RWONLY, O_RDWR are not flags
+	s := accModeName(fl & OpenAccessModeMask)
+	flags := uint32(fl &^ OpenAccessModeMask)
+	if flags != 0 {
+		s = s + "+" + flagString(flags, openFlagNames)
+	}
+	return s
+}
+
+// Return true if OpenReadOnly is set.
+func (fl OpenFlags) IsReadOnly() bool {
+	return fl&OpenAccessModeMask == OpenReadOnly
+}
+
+// Return true if OpenWriteOnly is set.
+func (fl OpenFlags) IsWriteOnly() bool {
+	return fl&OpenAccessModeMask == OpenWriteOnly
+}
+
+// Return true if OpenReadWrite is set.
+func (fl OpenFlags) IsReadWrite() bool {
+	return fl&OpenAccessModeMask == OpenReadWrite
+}
+
+func accModeName(flags OpenFlags) string {
+	switch flags {
+	case OpenReadOnly:
+		return "OpenReadOnly"
+	case OpenWriteOnly:
+		return "OpenWriteOnly"
+	case OpenReadWrite:
+		return "OpenReadWrite"
+	default:
+		return ""
+	}
+}
+
+var openFlagNames = []flagName{
+	{uint32(OpenAppend), "OpenAppend"},
+	{uint32(OpenCreate), "OpenCreate"},
+	{uint32(OpenDirectory), "OpenDirectory"},
+	{uint32(OpenExclusive), "OpenExclusive"},
+	{uint32(OpenNonblock), "OpenNonblock"},
+	{uint32(OpenSync), "OpenSync"},
+	{uint32(OpenTruncate), "OpenTruncate"},
+}
+
+// The OpenResponseFlags are returned in the OpenResponse.
+type OpenResponseFlags uint32
+
+const (
+	OpenDirectIO    OpenResponseFlags = 1 << 0 // bypass page cache for this open file
+	OpenKeepCache   OpenResponseFlags = 1 << 1 // don't invalidate the data cache on open
+	OpenNonSeekable OpenResponseFlags = 1 << 2 // mark the file as non-seekable (not supported on OS X)
+
+	OpenPurgeAttr OpenResponseFlags = 1 << 30 // OS X
+	OpenPurgeUBC  OpenResponseFlags = 1 << 31 // OS X
+)
+
+func (fl OpenResponseFlags) String() string {
+	return flagString(uint32(fl), openResponseFlagNames)
+}
+
+var openResponseFlagNames = []flagName{
+	{uint32(OpenDirectIO), "OpenDirectIO"},
+	{uint32(OpenKeepCache), "OpenKeepCache"},
+	{uint32(OpenNonSeekable), "OpenNonSeekable"},
+	{uint32(OpenPurgeAttr), "OpenPurgeAttr"},
+	{uint32(OpenPurgeUBC), "OpenPurgeUBC"},
+}
+
+// The InitFlags are used in the Init exchange.
+type InitFlags uint32
+
+const (
+	InitAsyncRead     InitFlags = 1 << 0
+	InitPosixLocks    InitFlags = 1 << 1
+	InitFileOps       InitFlags = 1 << 2
+	InitAtomicTrunc   InitFlags = 1 << 3
+	InitExportSupport InitFlags = 1 << 4
+	InitBigWrites     InitFlags = 1 << 5
+	// Do not mask file access modes with umask. Not supported on OS X.
+	InitDontMask        InitFlags = 1 << 6
+	InitSpliceWrite     InitFlags = 1 << 7
+	InitSpliceMove      InitFlags = 1 << 8
+	InitSpliceRead      InitFlags = 1 << 9
+	InitFlockLocks      InitFlags = 1 << 10
+	InitHasIoctlDir     InitFlags = 1 << 11
+	InitAutoInvalData   InitFlags = 1 << 12
+	InitDoReaddirplus   InitFlags = 1 << 13
+	InitReaddirplusAuto InitFlags = 1 << 14
+	InitAsyncDIO        InitFlags = 1 << 15
+	InitWritebackCache  InitFlags = 1 << 16
+	InitNoOpenSupport   InitFlags = 1 << 17
+
+	InitCaseSensitive InitFlags = 1 << 29 // OS X only
+	InitVolRename     InitFlags = 1 << 30 // OS X only
+	InitXtimes        InitFlags = 1 << 31 // OS X only
+)
+
+type flagName struct {
+	bit  uint32
+	name string
+}
+
+var initFlagNames = []flagName{
+	{uint32(InitAsyncRead), "InitAsyncRead"},
+	{uint32(InitPosixLocks), "InitPosixLocks"},
+	{uint32(InitFileOps), "InitFileOps"},
+	{uint32(InitAtomicTrunc), "InitAtomicTrunc"},
+	{uint32(InitExportSupport), "InitExportSupport"},
+	{uint32(InitBigWrites), "InitBigWrites"},
+	{uint32(InitDontMask), "InitDontMask"},
+	{uint32(InitSpliceWrite), "InitSpliceWrite"},
+	{uint32(InitSpliceMove), "InitSpliceMove"},
+	{uint32(InitSpliceRead), "InitSpliceRead"},
+	{uint32(InitFlockLocks), "InitFlockLocks"},
+	{uint32(InitHasIoctlDir), "InitHasIoctlDir"},
+	{uint32(InitAutoInvalData), "InitAutoInvalData"},
+	{uint32(InitDoReaddirplus), "InitDoReaddirplus"},
+	{uint32(InitReaddirplusAuto), "InitReaddirplusAuto"},
+	{uint32(InitAsyncDIO), "InitAsyncDIO"},
+	{uint32(InitWritebackCache), "InitWritebackCache"},
+	{uint32(InitNoOpenSupport), "InitNoOpenSupport"},
+
+	{uint32(InitCaseSensitive), "InitCaseSensitive"},
+	{uint32(InitVolRename), "InitVolRename"},
+	{uint32(InitXtimes), "InitXtimes"},
+}
+
+func (fl InitFlags) String() string {
+	return flagString(uint32(fl), initFlagNames)
+}
+
+func flagString(f uint32, names []flagName) string {
+	var s string
+
+	if f == 0 {
+		return "0"
+	}
+
+	for _, n := range names {
+		if f&n.bit != 0 {
+			s += "+" + n.name
+			f &^= n.bit
+		}
+	}
+	if f != 0 {
+		s += fmt.Sprintf("%+#x", f)
+	}
+	return s[1:]
+}
+
+// The ReleaseFlags are used in the Release exchange.
+type ReleaseFlags uint32
+
+const (
+	ReleaseFlush ReleaseFlags = 1 << 0
+)
+
+func (fl ReleaseFlags) String() string {
+	return flagString(uint32(fl), releaseFlagNames)
+}
+
+var releaseFlagNames = []flagName{
+	{uint32(ReleaseFlush), "ReleaseFlush"},
+}
+
+// Opcodes
+const (
+	opLookup      = 1
+	opForget      = 2 // no reply
+	opGetattr     = 3
+	opSetattr     = 4
+	opReadlink    = 5
+	opSymlink     = 6
+	opMknod       = 8
+	opMkdir       = 9
+	opUnlink      = 10
+	opRmdir       = 11
+	opRename      = 12
+	opLink        = 13
+	opOpen        = 14
+	opRead        = 15
+	opWrite       = 16
+	opStatfs      = 17
+	opRelease     = 18
+	opFsync       = 20
+	opSetxattr    = 21
+	opGetxattr    = 22
+	opListxattr   = 23
+	opRemovexattr = 24
+	opFlush       = 25
+	opInit        = 26
+	opOpendir     = 27
+	opReaddir     = 28
+	opReleasedir  = 29
+	opFsyncdir    = 30
+	opGetlk       = 31
+	opSetlk       = 32
+	opSetlkw      = 33
+	opAccess      = 34
+	opCreate      = 35
+	opInterrupt   = 36
+	opBmap        = 37
+	opDestroy     = 38
+	opIoctl       = 39 // Linux?
+	opPoll        = 40 // Linux?
+
+	// OS X
+	opSetvolname = 61
+	opGetxtimes  = 62
+	opExchange   = 63
+)
+
+type entryOut struct {
+	Nodeid         uint64 // Inode ID
+	Generation     uint64 // Inode generation
+	EntryValid     uint64 // Cache timeout for the name
+	AttrValid      uint64 // Cache timeout for the attributes
+	EntryValidNsec uint32
+	AttrValidNsec  uint32
+	Attr           attr
+}
+
+func entryOutSize(p Protocol) uintptr {
+	switch {
+	case p.LT(Protocol{7, 9}):
+		return unsafe.Offsetof(entryOut{}.Attr) + unsafe.Offsetof(entryOut{}.Attr.Blksize)
+	default:
+		return unsafe.Sizeof(entryOut{})
+	}
+}
+
+type forgetIn struct {
+	Nlookup uint64
+}
+
+type getattrIn struct {
+	GetattrFlags uint32
+	_            uint32
+	Fh           uint64
+}
+
+type attrOut struct {
+	AttrValid     uint64 // Cache timeout for the attributes
+	AttrValidNsec uint32
+	_             uint32
+	Attr          attr
+}
+
+func attrOutSize(p Protocol) uintptr {
+	switch {
+	case p.LT(Protocol{7, 9}):
+		return unsafe.Offsetof(attrOut{}.Attr) + unsafe.Offsetof(attrOut{}.Attr.Blksize)
+	default:
+		return unsafe.Sizeof(attrOut{})
+	}
+}
+
+// OS X
+type getxtimesOut struct {
+	Bkuptime     uint64
+	Crtime       uint64
+	BkuptimeNsec uint32
+	CrtimeNsec   uint32
+}
+
+type mknodIn struct {
+	Mode  uint32
+	Rdev  uint32
+	Umask uint32
+	_     uint32
+	// "filename\x00" follows.
+}
+
+func mknodInSize(p Protocol) uintptr {
+	switch {
+	case p.LT(Protocol{7, 12}):
+		return unsafe.Offsetof(mknodIn{}.Umask)
+	default:
+		return unsafe.Sizeof(mknodIn{})
+	}
+}
+
+type mkdirIn struct {
+	Mode  uint32
+	Umask uint32
+	// filename follows
+}
+
+func mkdirInSize(p Protocol) uintptr {
+	switch {
+	case p.LT(Protocol{7, 12}):
+		return unsafe.Offsetof(mkdirIn{}.Umask) + 4
+	default:
+		return unsafe.Sizeof(mkdirIn{})
+	}
+}
+
+type renameIn struct {
+	Newdir uint64
+	// "oldname\x00newname\x00" follows
+}
+
+// OS X
+type exchangeIn struct {
+	Olddir  uint64
+	Newdir  uint64
+	Options uint64
+	// "oldname\x00newname\x00" follows
+}
+
+type linkIn struct {
+	Oldnodeid uint64
+}
+
+type setattrInCommon struct {
+	Valid     uint32
+	_         uint32
+	Fh        uint64
+	Size      uint64
+	LockOwner uint64 // unused on OS X?
+	Atime     uint64
+	Mtime     uint64
+	Unused2   uint64
+	AtimeNsec uint32
+	MtimeNsec uint32
+	Unused3   uint32
+	Mode      uint32
+	Unused4   uint32
+	Uid       uint32
+	Gid       uint32
+	Unused5   uint32
+}
+
+type openIn struct {
+	Flags  uint32
+	Unused uint32
+}
+
+type openOut struct {
+	Fh        uint64
+	OpenFlags uint32
+	_         uint32
+}
+
+type createIn struct {
+	Flags uint32
+	Mode  uint32
+	Umask uint32
+	_     uint32
+}
+
+func createInSize(p Protocol) uintptr {
+	switch {
+	case p.LT(Protocol{7, 12}):
+		return unsafe.Offsetof(createIn{}.Umask)
+	default:
+		return unsafe.Sizeof(createIn{})
+	}
+}
+
+type releaseIn struct {
+	Fh           uint64
+	Flags        uint32
+	ReleaseFlags uint32
+	LockOwner    uint32
+}
+
+type flushIn struct {
+	Fh         uint64
+	FlushFlags uint32
+	_          uint32
+	LockOwner  uint64
+}
+
+type readIn struct {
+	Fh        uint64
+	Offset    uint64
+	Size      uint32
+	ReadFlags uint32
+	LockOwner uint64
+	Flags     uint32
+	_         uint32
+}
+
+func readInSize(p Protocol) uintptr {
+	switch {
+	case p.LT(Protocol{7, 9}):
+		return unsafe.Offsetof(readIn{}.ReadFlags) + 4
+	default:
+		return unsafe.Sizeof(readIn{})
+	}
+}
+
+// The ReadFlags are passed in ReadRequest.
+type ReadFlags uint32
+
+const (
+	// LockOwner field is valid.
+	ReadLockOwner ReadFlags = 1 << 1
+)
+
+var readFlagNames = []flagName{
+	{uint32(ReadLockOwner), "ReadLockOwner"},
+}
+
+func (fl ReadFlags) String() string {
+	return flagString(uint32(fl), readFlagNames)
+}
+
+type writeIn struct {
+	Fh         uint64
+	Offset     uint64
+	Size       uint32
+	WriteFlags uint32
+	LockOwner  uint64
+	Flags      uint32
+	_          uint32
+}
+
+func writeInSize(p Protocol) uintptr {
+	switch {
+	case p.LT(Protocol{7, 9}):
+		return unsafe.Offsetof(writeIn{}.LockOwner)
+	default:
+		return unsafe.Sizeof(writeIn{})
+	}
+}
+
+type writeOut struct {
+	Size uint32
+	_    uint32
+}
+
+// The WriteFlags are passed in WriteRequest.
+type WriteFlags uint32
+
+const (
+	WriteCache WriteFlags = 1 << 0
+	// LockOwner field is valid.
+	WriteLockOwner WriteFlags = 1 << 1
+)
+
+var writeFlagNames = []flagName{
+	{uint32(WriteCache), "WriteCache"},
+	{uint32(WriteLockOwner), "WriteLockOwner"},
+}
+
+func (fl WriteFlags) String() string {
+	return flagString(uint32(fl), writeFlagNames)
+}
+
+const compatStatfsSize = 48
+
+type statfsOut struct {
+	St kstatfs
+}
+
+type fsyncIn struct {
+	Fh         uint64
+	FsyncFlags uint32
+	_          uint32
+}
+
+type setxattrInCommon struct {
+	Size  uint32
+	Flags uint32
+}
+
+func (setxattrInCommon) position() uint32 {
+	return 0
+}
+
+type getxattrInCommon struct {
+	Size uint32
+	_    uint32
+}
+
+func (getxattrInCommon) position() uint32 {
+	return 0
+}
+
+type getxattrOut struct {
+	Size uint32
+	_    uint32
+}
+
+type lkIn struct {
+	Fh      uint64
+	Owner   uint64
+	Lk      fileLock
+	LkFlags uint32
+	_       uint32
+}
+
+func lkInSize(p Protocol) uintptr {
+	switch {
+	case p.LT(Protocol{7, 9}):
+		return unsafe.Offsetof(lkIn{}.LkFlags)
+	default:
+		return unsafe.Sizeof(lkIn{})
+	}
+}
+
+type lkOut struct {
+	Lk fileLock
+}
+
+type accessIn struct {
+	Mask uint32
+	_    uint32
+}
+
+type initIn struct {
+	Major        uint32
+	Minor        uint32
+	MaxReadahead uint32
+	Flags        uint32
+}
+
+const initInSize = int(unsafe.Sizeof(initIn{}))
+
+type initOut struct {
+	Major        uint32
+	Minor        uint32
+	MaxReadahead uint32
+	Flags        uint32
+	Unused       uint32
+	MaxWrite     uint32
+}
+
+type interruptIn struct {
+	Unique uint64
+}
+
+type bmapIn struct {
+	Block     uint64
+	BlockSize uint32
+	_         uint32
+}
+
+type bmapOut struct {
+	Block uint64
+}
+
+type inHeader struct {
+	Len    uint32
+	Opcode uint32
+	Unique uint64
+	Nodeid uint64
+	Uid    uint32
+	Gid    uint32
+	Pid    uint32
+	_      uint32
+}
+
+const inHeaderSize = int(unsafe.Sizeof(inHeader{}))
+
+type outHeader struct {
+	Len    uint32
+	Error  int32
+	Unique uint64
+}
+
+type dirent struct {
+	Ino     uint64
+	Off     uint64
+	Namelen uint32
+	Type    uint32
+	Name    [0]byte
+}
+
+const direntSize = 8 + 8 + 4 + 4
+
+const (
+	notifyCodePoll       int32 = 1
+	notifyCodeInvalInode int32 = 2
+	notifyCodeInvalEntry int32 = 3
+)
+
+type notifyInvalInodeOut struct {
+	Ino uint64
+	Off int64
+	Len int64
+}
+
+type notifyInvalEntryOut struct {
+	Parent  uint64
+	Namelen uint32
+	_       uint32
+}
diff --git a/vendor/bazil.org/fuse/fuse_kernel_darwin.go b/vendor/bazil.org/fuse/fuse_kernel_darwin.go
new file mode 100644
index 000000000..b9873fdf3
--- /dev/null
+++ b/vendor/bazil.org/fuse/fuse_kernel_darwin.go
@@ -0,0 +1,88 @@
+package fuse
+
+import (
+	"time"
+)
+
+type attr struct {
+	Ino        uint64
+	Size       uint64
+	Blocks     uint64
+	Atime      uint64
+	Mtime      uint64
+	Ctime      uint64
+	Crtime_    uint64 // OS X only
+	AtimeNsec  uint32
+	MtimeNsec  uint32
+	CtimeNsec  uint32
+	CrtimeNsec uint32 // OS X only
+	Mode       uint32
+	Nlink      uint32
+	Uid        uint32
+	Gid        uint32
+	Rdev       uint32
+	Flags_     uint32 // OS X only; see chflags(2)
+	Blksize    uint32
+	padding    uint32
+}
+
+func (a *attr) SetCrtime(s uint64, ns uint32) {
+	a.Crtime_, a.CrtimeNsec = s, ns
+}
+
+func (a *attr) SetFlags(f uint32) {
+	a.Flags_ = f
+}
+
+type setattrIn struct {
+	setattrInCommon
+
+	// OS X only
+	Bkuptime_    uint64
+	Chgtime_     uint64
+	Crtime       uint64
+	BkuptimeNsec uint32
+	ChgtimeNsec  uint32
+	CrtimeNsec   uint32
+	Flags_       uint32 // see chflags(2)
+}
+
+func (in *setattrIn) BkupTime() time.Time {
+	return time.Unix(int64(in.Bkuptime_), int64(in.BkuptimeNsec))
+}
+
+func (in *setattrIn) Chgtime() time.Time {
+	return time.Unix(int64(in.Chgtime_), int64(in.ChgtimeNsec))
+}
+
+func (in *setattrIn) Flags() uint32 {
+	return in.Flags_
+}
+
+func openFlags(flags uint32) OpenFlags {
+	return OpenFlags(flags)
+}
+
+type getxattrIn struct {
+	getxattrInCommon
+
+	// OS X only
+	Position uint32
+	Padding  uint32
+}
+
+func (g *getxattrIn) position() uint32 {
+	return g.Position
+}
+
+type setxattrIn struct {
+	setxattrInCommon
+
+	// OS X only
+	Position uint32
+	Padding  uint32
+}
+
+func (s *setxattrIn) position() uint32 {
+	return s.Position
+}
diff --git a/vendor/bazil.org/fuse/fuse_kernel_freebsd.go b/vendor/bazil.org/fuse/fuse_kernel_freebsd.go
new file mode 100644
index 000000000..b1141e41d
--- /dev/null
+++ b/vendor/bazil.org/fuse/fuse_kernel_freebsd.go
@@ -0,0 +1,62 @@
+package fuse
+
+import "time"
+
+type attr struct {
+	Ino       uint64
+	Size      uint64
+	Blocks    uint64
+	Atime     uint64
+	Mtime     uint64
+	Ctime     uint64
+	AtimeNsec uint32
+	MtimeNsec uint32
+	CtimeNsec uint32
+	Mode      uint32
+	Nlink     uint32
+	Uid       uint32
+	Gid       uint32
+	Rdev      uint32
+	Blksize   uint32
+	padding   uint32
+}
+
+func (a *attr) Crtime() time.Time {
+	return time.Time{}
+}
+
+func (a *attr) SetCrtime(s uint64, ns uint32) {
+	// ignored on freebsd
+}
+
+func (a *attr) SetFlags(f uint32) {
+	// ignored on freebsd
+}
+
+type setattrIn struct {
+	setattrInCommon
+}
+
+func (in *setattrIn) BkupTime() time.Time {
+	return time.Time{}
+}
+
+func (in *setattrIn) Chgtime() time.Time {
+	return time.Time{}
+}
+
+func (in *setattrIn) Flags() uint32 {
+	return 0
+}
+
+func openFlags(flags uint32) OpenFlags {
+	return OpenFlags(flags)
+}
+
+type getxattrIn struct {
+	getxattrInCommon
+}
+
+type setxattrIn struct {
+	setxattrInCommon
+}
diff --git a/vendor/bazil.org/fuse/fuse_kernel_linux.go b/vendor/bazil.org/fuse/fuse_kernel_linux.go
new file mode 100644
index 000000000..d3ba86617
--- /dev/null
+++ b/vendor/bazil.org/fuse/fuse_kernel_linux.go
@@ -0,0 +1,70 @@
+package fuse
+
+import "time"
+
+type attr struct {
+	Ino       uint64
+	Size      uint64
+	Blocks    uint64
+	Atime     uint64
+	Mtime     uint64
+	Ctime     uint64
+	AtimeNsec uint32
+	MtimeNsec uint32
+	CtimeNsec uint32
+	Mode      uint32
+	Nlink     uint32
+	Uid       uint32
+	Gid       uint32
+	Rdev      uint32
+	Blksize   uint32
+	padding   uint32
+}
+
+func (a *attr) Crtime() time.Time {
+	return time.Time{}
+}
+
+func (a *attr) SetCrtime(s uint64, ns uint32) {
+	// Ignored on Linux.
+}
+
+func (a *attr) SetFlags(f uint32) {
+	// Ignored on Linux.
+}
+
+type setattrIn struct {
+	setattrInCommon
+}
+
+func (in *setattrIn) BkupTime() time.Time {
+	return time.Time{}
+}
+
+func (in *setattrIn) Chgtime() time.Time {
+	return time.Time{}
+}
+
+func (in *setattrIn) Flags() uint32 {
+	return 0
+}
+
+func openFlags(flags uint32) OpenFlags {
+	// on amd64, the 32-bit O_LARGEFILE flag is always seen;
+	// on i386, the flag probably depends on the app
+	// requesting, but in any case should be utterly
+	// uninteresting to us here; our kernel protocol messages
+	// are not directly related to the client app's kernel
+	// API/ABI
+	flags &^= 0x8000
+
+	return OpenFlags(flags)
+}
+
+type getxattrIn struct {
+	getxattrInCommon
+}
+
+type setxattrIn struct {
+	setxattrInCommon
+}
diff --git a/vendor/bazil.org/fuse/fuse_kernel_std.go b/vendor/bazil.org/fuse/fuse_kernel_std.go
new file mode 100644
index 000000000..074cfd322
--- /dev/null
+++ b/vendor/bazil.org/fuse/fuse_kernel_std.go
@@ -0,0 +1 @@
+package fuse
diff --git a/vendor/bazil.org/fuse/fuse_linux.go b/vendor/bazil.org/fuse/fuse_linux.go
new file mode 100644
index 000000000..5fb96f9ae
--- /dev/null
+++ b/vendor/bazil.org/fuse/fuse_linux.go
@@ -0,0 +1,7 @@
+package fuse
+
+// Maximum file write size we are prepared to receive from the kernel.
+//
+// Linux 4.2.0 has been observed to cap this value at 128kB
+// (FUSE_MAX_PAGES_PER_REQ=32, 4kB pages).
+const maxWrite = 128 * 1024
diff --git a/vendor/bazil.org/fuse/fuseutil/fuseutil.go b/vendor/bazil.org/fuse/fuseutil/fuseutil.go
new file mode 100644
index 000000000..b3f52b73b
--- /dev/null
+++ b/vendor/bazil.org/fuse/fuseutil/fuseutil.go
@@ -0,0 +1,20 @@
+package fuseutil // import "bazil.org/fuse/fuseutil"
+
+import (
+	"bazil.org/fuse"
+)
+
+// HandleRead handles a read request assuming that data is the entire file content.
+// It adjusts the amount returned in resp according to req.Offset and req.Size.
+func HandleRead(req *fuse.ReadRequest, resp *fuse.ReadResponse, data []byte) {
+	if req.Offset >= int64(len(data)) {
+		data = nil
+	} else {
+		data = data[req.Offset:]
+	}
+	if len(data) > req.Size {
+		data = data[:req.Size]
+	}
+	n := copy(resp.Data[:req.Size], data)
+	resp.Data = resp.Data[:n]
+}
diff --git a/vendor/bazil.org/fuse/mount.go b/vendor/bazil.org/fuse/mount.go
new file mode 100644
index 000000000..8054e9021
--- /dev/null
+++ b/vendor/bazil.org/fuse/mount.go
@@ -0,0 +1,38 @@
+package fuse
+
+import (
+	"bufio"
+	"errors"
+	"io"
+	"log"
+	"sync"
+)
+
+var (
+	// ErrOSXFUSENotFound is returned from Mount when the OSXFUSE
+	// installation is not detected.
+	//
+	// Only happens on OS X. Make sure OSXFUSE is installed, or see
+	// OSXFUSELocations for customization.
+	ErrOSXFUSENotFound = errors.New("cannot locate OSXFUSE")
+)
+
+func neverIgnoreLine(line string) bool {
+	return false
+}
+
+func lineLogger(wg *sync.WaitGroup, prefix string, ignore func(line string) bool, r io.ReadCloser) {
+	defer wg.Done()
+
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if ignore(line) {
+			continue
+		}
+		log.Printf("%s: %s", prefix, line)
+	}
+	if err := scanner.Err(); err != nil {
+		log.Printf("%s, error reading: %v", prefix, err)
+	}
+}
diff --git a/vendor/bazil.org/fuse/mount_darwin.go b/vendor/bazil.org/fuse/mount_darwin.go
new file mode 100644
index 000000000..c1c36e62b
--- /dev/null
+++ b/vendor/bazil.org/fuse/mount_darwin.go
@@ -0,0 +1,208 @@
+package fuse
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"path"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+)
+
+var (
+	errNoAvail   = errors.New("no available fuse devices")
+	errNotLoaded = errors.New("osxfuse is not loaded")
+)
+
+func loadOSXFUSE(bin string) error {
+	cmd := exec.Command(bin)
+	cmd.Dir = "/"
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	err := cmd.Run()
+	return err
+}
+
+func openOSXFUSEDev(devPrefix string) (*os.File, error) {
+	var f *os.File
+	var err error
+	for i := uint64(0); ; i++ {
+		path := devPrefix + strconv.FormatUint(i, 10)
+		f, err = os.OpenFile(path, os.O_RDWR, 0000)
+		if os.IsNotExist(err) {
+			if i == 0 {
+				// not even the first device was found -> fuse is not loaded
+				return nil, errNotLoaded
+			}
+
+			// we've run out of kernel-provided devices
+			return nil, errNoAvail
+		}
+
+		if err2, ok := err.(*os.PathError); ok && err2.Err == syscall.EBUSY {
+			// try the next one
+			continue
+		}
+
+		if err != nil {
+			return nil, err
+		}
+		return f, nil
+	}
+}
+
+func handleMountOSXFUSE(helperName string, errCh chan<- error) func(line string) (ignore bool) {
+	var noMountpointPrefix = helperName + `: `
+	const noMountpointSuffix = `: No such file or directory`
+	return func(line string) (ignore bool) {
+		if strings.HasPrefix(line, noMountpointPrefix) && strings.HasSuffix(line, noMountpointSuffix) {
+			// re-extract it from the error message in case some layer
+			// changed the path
+			mountpoint := line[len(noMountpointPrefix) : len(line)-len(noMountpointSuffix)]
+			err := &MountpointDoesNotExistError{
+				Path: mountpoint,
+			}
+			select {
+			case errCh <- err:
+				return true
+			default:
+				// not the first error; fall back to logging it
+				return false
+			}
+		}
+
+		return false
+	}
+}
+
+// isBoringMountOSXFUSEError returns whether the Wait error is
+// uninteresting; exit status 64 is.
+func isBoringMountOSXFUSEError(err error) bool {
+	if err, ok := err.(*exec.ExitError); ok && err.Exited() {
+		if status, ok := err.Sys().(syscall.WaitStatus); ok && status.ExitStatus() == 64 {
+			return true
+		}
+	}
+	return false
+}
+
+func callMount(bin string, daemonVar string, dir string, conf *mountConfig, f *os.File, ready chan<- struct{}, errp *error) error {
+	for k, v := range conf.options {
+		if strings.Contains(k, ",") || strings.Contains(v, ",") {
+			// Silly limitation but the mount helper does not
+			// understand any escaping. See TestMountOptionCommaError.
+			return fmt.Errorf("mount options cannot contain commas on darwin: %q=%q", k, v)
+		}
+	}
+	cmd := exec.Command(
+		bin,
+		"-o", conf.getOptions(),
+		// Tell osxfuse-kext how large our buffer is. It must split
+		// writes larger than this into multiple writes.
+		//
+		// OSXFUSE seems to ignore InitResponse.MaxWrite, and uses
+		// this instead.
+		"-o", "iosize="+strconv.FormatUint(maxWrite, 10),
+		// refers to fd passed in cmd.ExtraFiles
+		"3",
+		dir,
+	)
+	cmd.ExtraFiles = []*os.File{f}
+	cmd.Env = os.Environ()
+	// OSXFUSE <3.3.0
+	cmd.Env = append(cmd.Env, "MOUNT_FUSEFS_CALL_BY_LIB=")
+	// OSXFUSE >=3.3.0
+	cmd.Env = append(cmd.Env, "MOUNT_OSXFUSE_CALL_BY_LIB=")
+
+	daemon := os.Args[0]
+	if daemonVar != "" {
+		cmd.Env = append(cmd.Env, daemonVar+"="+daemon)
+	}
+
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return fmt.Errorf("setting up mount_osxfusefs stderr: %v", err)
+	}
+	stderr, err := cmd.StderrPipe()
+	if err != nil {
+		return fmt.Errorf("setting up mount_osxfusefs stderr: %v", err)
+	}
+
+	if err := cmd.Start(); err != nil {
+		return fmt.Errorf("mount_osxfusefs: %v", err)
+	}
+	helperErrCh := make(chan error, 1)
+	go func() {
+		var wg sync.WaitGroup
+		wg.Add(2)
+		go lineLogger(&wg, "mount helper output", neverIgnoreLine, stdout)
+		helperName := path.Base(bin)
+		go lineLogger(&wg, "mount helper error", handleMountOSXFUSE(helperName, helperErrCh), stderr)
+		wg.Wait()
+		if err := cmd.Wait(); err != nil {
+			// see if we have a better error to report
+			select {
+			case helperErr := <-helperErrCh:
+				// log the Wait error if it's not what we expected
+				if !isBoringMountOSXFUSEError(err) {
+					log.Printf("mount helper failed: %v", err)
+				}
+				// and now return what we grabbed from stderr as the real
+				// error
+				*errp = helperErr
+				close(ready)
+				return
+			default:
+				// nope, fall back to generic message
+			}
+
+			*errp = fmt.Errorf("mount_osxfusefs: %v", err)
+			close(ready)
+			return
+		}
+
+		*errp = nil
+		close(ready)
+	}()
+	return nil
+}
+
+func mount(dir string, conf *mountConfig, ready chan<- struct{}, errp *error) (*os.File, error) {
+	locations := conf.osxfuseLocations
+	if locations == nil {
+		locations = []OSXFUSEPaths{
+			OSXFUSELocationV3,
+			OSXFUSELocationV2,
+		}
+	}
+	for _, loc := range locations {
+		if _, err := os.Stat(loc.Mount); os.IsNotExist(err) {
+			// try the other locations
+			continue
+		}
+
+		f, err := openOSXFUSEDev(loc.DevicePrefix)
+		if err == errNotLoaded {
+			err = loadOSXFUSE(loc.Load)
+			if err != nil {
+				return nil, err
+			}
+			// try again
+			f, err = openOSXFUSEDev(loc.DevicePrefix)
+		}
+		if err != nil {
+			return nil, err
+		}
+		err = callMount(loc.Mount, loc.DaemonVar, dir, conf, f, ready, errp)
+		if err != nil {
+			f.Close()
+			return nil, err
+		}
+		return f, nil
+	}
+	return nil, ErrOSXFUSENotFound
+}
diff --git a/vendor/bazil.org/fuse/mount_freebsd.go b/vendor/bazil.org/fuse/mount_freebsd.go
new file mode 100644
index 000000000..70bb41024
--- /dev/null
+++ b/vendor/bazil.org/fuse/mount_freebsd.go
@@ -0,0 +1,111 @@
+package fuse
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"strings"
+	"sync"
+	"syscall"
+)
+
+func handleMountFusefsStderr(errCh chan<- error) func(line string) (ignore bool) {
+	return func(line string) (ignore bool) {
+		const (
+			noMountpointPrefix = `mount_fusefs: `
+			noMountpointSuffix = `: No such file or directory`
+		)
+		if strings.HasPrefix(line, noMountpointPrefix) && strings.HasSuffix(line, noMountpointSuffix) {
+			// re-extract it from the error message in case some layer
+			// changed the path
+			mountpoint := line[len(noMountpointPrefix) : len(line)-len(noMountpointSuffix)]
+			err := &MountpointDoesNotExistError{
+				Path: mountpoint,
+			}
+			select {
+			case errCh <- err:
+				return true
+			default:
+				// not the first error; fall back to logging it
+				return false
+			}
+		}
+
+		return false
+	}
+}
+
+// isBoringMountFusefsError returns whether the Wait error is
+// uninteresting; exit status 1 is.
+func isBoringMountFusefsError(err error) bool {
+	if err, ok := err.(*exec.ExitError); ok && err.Exited() {
+		if status, ok := err.Sys().(syscall.WaitStatus); ok && status.ExitStatus() == 1 {
+			return true
+		}
+	}
+	return false
+}
+
+func mount(dir string, conf *mountConfig, ready chan<- struct{}, errp *error) (*os.File, error) {
+	for k, v := range conf.options {
+		if strings.Contains(k, ",") || strings.Contains(v, ",") {
+			// Silly limitation but the mount helper does not
+			// understand any escaping. See TestMountOptionCommaError.
+			return nil, fmt.Errorf("mount options cannot contain commas on FreeBSD: %q=%q", k, v)
+		}
+	}
+
+	f, err := os.OpenFile("/dev/fuse", os.O_RDWR, 0000)
+	if err != nil {
+		*errp = err
+		return nil, err
+	}
+
+	cmd := exec.Command(
+		"/sbin/mount_fusefs",
+		"--safe",
+		"-o", conf.getOptions(),
+		"3",
+		dir,
+	)
+	cmd.ExtraFiles = []*os.File{f}
+
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return nil, fmt.Errorf("setting up mount_fusefs stderr: %v", err)
+	}
+	stderr, err := cmd.StderrPipe()
+	if err != nil {
+		return nil, fmt.Errorf("setting up mount_fusefs stderr: %v", err)
+	}
+
+	if err := cmd.Start(); err != nil {
+		return nil, fmt.Errorf("mount_fusefs: %v", err)
+	}
+	helperErrCh := make(chan error, 1)
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go lineLogger(&wg, "mount helper output", neverIgnoreLine, stdout)
+	go lineLogger(&wg, "mount helper error", handleMountFusefsStderr(helperErrCh), stderr)
+	wg.Wait()
+	if err := cmd.Wait(); err != nil {
+		// see if we have a better error to report
+		select {
+		case helperErr := <-helperErrCh:
+			// log the Wait error if it's not what we expected
+			if !isBoringMountFusefsError(err) {
+				log.Printf("mount helper failed: %v", err)
+			}
+			// and now return what we grabbed from stderr as the real
+			// error
+			return nil, helperErr
+		default:
+			// nope, fall back to generic message
+		}
+		return nil, fmt.Errorf("mount_fusefs: %v", err)
+	}
+
+	close(ready)
+	return f, nil
+}
diff --git a/vendor/bazil.org/fuse/mount_linux.go b/vendor/bazil.org/fuse/mount_linux.go
new file mode 100644
index 000000000..197d1044e
--- /dev/null
+++ b/vendor/bazil.org/fuse/mount_linux.go
@@ -0,0 +1,150 @@
+package fuse
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"os/exec"
+	"strings"
+	"sync"
+	"syscall"
+)
+
+func handleFusermountStderr(errCh chan<- error) func(line string) (ignore bool) {
+	return func(line string) (ignore bool) {
+		if line == `fusermount: failed to open /etc/fuse.conf: Permission denied` {
+			// Silence this particular message, it occurs way too
+			// commonly and isn't very relevant to whether the mount
+			// succeeds or not.
+			return true
+		}
+
+		const (
+			noMountpointPrefix = `fusermount: failed to access mountpoint `
+			noMountpointSuffix = `: No such file or directory`
+		)
+		if strings.HasPrefix(line, noMountpointPrefix) && strings.HasSuffix(line, noMountpointSuffix) {
+			// re-extract it from the error message in case some layer
+			// changed the path
+			mountpoint := line[len(noMountpointPrefix) : len(line)-len(noMountpointSuffix)]
+			err := &MountpointDoesNotExistError{
+				Path: mountpoint,
+			}
+			select {
+			case errCh <- err:
+				return true
+			default:
+				// not the first error; fall back to logging it
+				return false
+			}
+		}
+
+		return false
+	}
+}
+
+// isBoringFusermountError returns whether the Wait error is
+// uninteresting; exit status 1 is.
+func isBoringFusermountError(err error) bool {
+	if err, ok := err.(*exec.ExitError); ok && err.Exited() {
+		if status, ok := err.Sys().(syscall.WaitStatus); ok && status.ExitStatus() == 1 {
+			return true
+		}
+	}
+	return false
+}
+
+func mount(dir string, conf *mountConfig, ready chan<- struct{}, errp *error) (fusefd *os.File, err error) {
+	// linux mount is never delayed
+	close(ready)
+
+	fds, err := syscall.Socketpair(syscall.AF_FILE, syscall.SOCK_STREAM, 0)
+	if err != nil {
+		return nil, fmt.Errorf("socketpair error: %v", err)
+	}
+
+	writeFile := os.NewFile(uintptr(fds[0]), "fusermount-child-writes")
+	defer writeFile.Close()
+
+	readFile := os.NewFile(uintptr(fds[1]), "fusermount-parent-reads")
+	defer readFile.Close()
+
+	cmd := exec.Command(
+		"fusermount",
+		"-o", conf.getOptions(),
+		"--",
+		dir,
+	)
+	cmd.Env = append(os.Environ(), "_FUSE_COMMFD=3")
+
+	cmd.ExtraFiles = []*os.File{writeFile}
+
+	var wg sync.WaitGroup
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return nil, fmt.Errorf("setting up fusermount stderr: %v", err)
+	}
+	stderr, err := cmd.StderrPipe()
+	if err != nil {
+		return nil, fmt.Errorf("setting up fusermount stderr: %v", err)
+	}
+
+	if err := cmd.Start(); err != nil {
+		return nil, fmt.Errorf("fusermount: %v", err)
+	}
+	helperErrCh := make(chan error, 1)
+	wg.Add(2)
+	go lineLogger(&wg, "mount helper output", neverIgnoreLine, stdout)
+	go lineLogger(&wg, "mount helper error", handleFusermountStderr(helperErrCh), stderr)
+	wg.Wait()
+	if err := cmd.Wait(); err != nil {
+		// see if we have a better error to report
+		select {
+		case helperErr := <-helperErrCh:
+			// log the Wait error if it's not what we expected
+			if !isBoringFusermountError(err) {
+				log.Printf("mount helper failed: %v", err)
+			}
+			// and now return what we grabbed from stderr as the real
+			// error
+			return nil, helperErr
+		default:
+			// nope, fall back to generic message
+		}
+
+		return nil, fmt.Errorf("fusermount: %v", err)
+	}
+
+	c, err := net.FileConn(readFile)
+	if err != nil {
+		return nil, fmt.Errorf("FileConn from fusermount socket: %v", err)
+	}
+	defer c.Close()
+
+	uc, ok := c.(*net.UnixConn)
+	if !ok {
+		return nil, fmt.Errorf("unexpected FileConn type; expected UnixConn, got %T", c)
+	}
+
+	buf := make([]byte, 32) // expect 1 byte
+	oob := make([]byte, 32) // expect 24 bytes
+	_, oobn, _, _, err := uc.ReadMsgUnix(buf, oob)
+	scms, err := syscall.ParseSocketControlMessage(oob[:oobn])
+	if err != nil {
+		return nil, fmt.Errorf("ParseSocketControlMessage: %v", err)
+	}
+	if len(scms) != 1 {
+		return nil, fmt.Errorf("expected 1 SocketControlMessage; got scms = %#v", scms)
+	}
+	scm := scms[0]
+	gotFds, err := syscall.ParseUnixRights(&scm)
+	if err != nil {
+		return nil, fmt.Errorf("syscall.ParseUnixRights: %v", err)
+	}
+	if len(gotFds) != 1 {
+		return nil, fmt.Errorf("wanted 1 fd; got %#v", gotFds)
+	}
+	f := os.NewFile(uintptr(gotFds[0]), "/dev/fuse")
+	return f, nil
+}
diff --git a/vendor/bazil.org/fuse/options.go b/vendor/bazil.org/fuse/options.go
new file mode 100644
index 000000000..65ce8a541
--- /dev/null
+++ b/vendor/bazil.org/fuse/options.go
@@ -0,0 +1,310 @@
+package fuse
+
+import (
+	"errors"
+	"strings"
+)
+
+func dummyOption(conf *mountConfig) error {
+	return nil
+}
+
+// mountConfig holds the configuration for a mount operation.
+// Use it by passing MountOption values to Mount.
+type mountConfig struct {
+	options          map[string]string
+	maxReadahead     uint32
+	initFlags        InitFlags
+	osxfuseLocations []OSXFUSEPaths
+}
+
+func escapeComma(s string) string {
+	s = strings.Replace(s, `\`, `\\`, -1)
+	s = strings.Replace(s, `,`, `\,`, -1)
+	return s
+}
+
+// getOptions makes a string of options suitable for passing to FUSE
+// mount flag `-o`. Returns an empty string if no options were set.
+// Any platform specific adjustments should happen before the call.
+func (m *mountConfig) getOptions() string {
+	var opts []string
+	for k, v := range m.options {
+		k = escapeComma(k)
+		if v != "" {
+			k += "=" + escapeComma(v)
+		}
+		opts = append(opts, k)
+	}
+	return strings.Join(opts, ",")
+}
+
+type mountOption func(*mountConfig) error
+
+// MountOption is passed to Mount to change the behavior of the mount.
+type MountOption mountOption
+
+// FSName sets the file system name (also called source) that is
+// visible in the list of mounted file systems.
+//
+// FreeBSD ignores this option.
+func FSName(name string) MountOption {
+	return func(conf *mountConfig) error {
+		conf.options["fsname"] = name
+		return nil
+	}
+}
+
+// Subtype sets the subtype of the mount. The main type is always
+// `fuse`. The type in a list of mounted file systems will look like
+// `fuse.foo`.
+//
+// OS X ignores this option.
+// FreeBSD ignores this option.
+func Subtype(fstype string) MountOption {
+	return func(conf *mountConfig) error {
+		conf.options["subtype"] = fstype
+		return nil
+	}
+}
+
+// LocalVolume sets the volume to be local (instead of network),
+// changing the behavior of Finder, Spotlight, and such.
+//
+// OS X only. Others ignore this option.
+func LocalVolume() MountOption {
+	return localVolume
+}
+
+// VolumeName sets the volume name shown in Finder.
+//
+// OS X only. Others ignore this option.
+func VolumeName(name string) MountOption {
+	return volumeName(name)
+}
+
+// NoAppleDouble makes OSXFUSE disallow files with names used by OS X
+// to store extended attributes on file systems that do not support
+// them natively.
+//
+// Such file names are:
+//
+//     ._*
+//     .DS_Store
+//
+// OS X only.  Others ignore this option.
+func NoAppleDouble() MountOption {
+	return noAppleDouble
+}
+
+// NoAppleXattr makes OSXFUSE disallow extended attributes with the
+// prefix "com.apple.". This disables persistent Finder state and
+// other such information.
+//
+// OS X only.  Others ignore this option.
+func NoAppleXattr() MountOption {
+	return noAppleXattr
+}
+
+// ExclCreate causes O_EXCL flag to be set for only "truly" exclusive creates,
+// i.e. create calls for which the initiator explicitly set the O_EXCL flag.
+//
+// OSXFUSE expects all create calls to return EEXIST in case the file
+// already exists, regardless of whether O_EXCL was specified or not.
+// To ensure this behavior, it normally sets OpenExclusive for all
+// Create calls, regardless of whether the original call had it set.
+// For distributed filesystems, that may force every file create to be
+// a distributed consensus action, causing undesirable delays.
+//
+// This option makes the FUSE filesystem see the original flag value,
+// and better decide when to ensure global consensus.
+//
+// Note that returning EEXIST on existing file create is still
+// expected with OSXFUSE, regardless of the presence of the
+// OpenExclusive flag.
+//
+// For more information, see
+// https://github.com/osxfuse/osxfuse/issues/209
+//
+// OS X only. Others ignore this options.
+// Requires OSXFUSE 3.4.1 or newer.
+func ExclCreate() MountOption {
+	return exclCreate
+}
+
+// DaemonTimeout sets the time in seconds between a request and a reply before
+// the FUSE mount is declared dead.
+//
+// OS X and FreeBSD only. Others ignore this option.
+func DaemonTimeout(name string) MountOption {
+	return daemonTimeout(name)
+}
+
+var ErrCannotCombineAllowOtherAndAllowRoot = errors.New("cannot combine AllowOther and AllowRoot")
+
+// AllowOther allows other users to access the file system.
+//
+// Only one of AllowOther or AllowRoot can be used.
+func AllowOther() MountOption {
+	return func(conf *mountConfig) error {
+		if _, ok := conf.options["allow_root"]; ok {
+			return ErrCannotCombineAllowOtherAndAllowRoot
+		}
+		conf.options["allow_other"] = ""
+		return nil
+	}
+}
+
+// AllowRoot allows other users to access the file system.
+//
+// Only one of AllowOther or AllowRoot can be used.
+//
+// FreeBSD ignores this option.
+func AllowRoot() MountOption {
+	return func(conf *mountConfig) error {
+		if _, ok := conf.options["allow_other"]; ok {
+			return ErrCannotCombineAllowOtherAndAllowRoot
+		}
+		conf.options["allow_root"] = ""
+		return nil
+	}
+}
+
+// AllowDev enables interpreting character or block special devices on the
+// filesystem.
+func AllowDev() MountOption {
+	return func(conf *mountConfig) error {
+		conf.options["dev"] = ""
+		return nil
+	}
+}
+
+// AllowSUID allows set-user-identifier or set-group-identifier bits to take
+// effect.
+func AllowSUID() MountOption {
+	return func(conf *mountConfig) error {
+		conf.options["suid"] = ""
+		return nil
+	}
+}
+
+// DefaultPermissions makes the kernel enforce access control based on
+// the file mode (as in chmod).
+//
+// Without this option, the Node itself decides what is and is not
+// allowed. This is normally ok because FUSE file systems cannot be
+// accessed by other users without AllowOther/AllowRoot.
+//
+// FreeBSD ignores this option.
+func DefaultPermissions() MountOption {
+	return func(conf *mountConfig) error {
+		conf.options["default_permissions"] = ""
+		return nil
+	}
+}
+
+// ReadOnly makes the mount read-only.
+func ReadOnly() MountOption {
+	return func(conf *mountConfig) error {
+		conf.options["ro"] = ""
+		return nil
+	}
+}
+
+// MaxReadahead sets the number of bytes that can be prefetched for
+// sequential reads. The kernel can enforce a maximum value lower than
+// this.
+//
+// This setting makes the kernel perform speculative reads that do not
+// originate from any client process. This usually tremendously
+// improves read performance.
+func MaxReadahead(n uint32) MountOption {
+	return func(conf *mountConfig) error {
+		conf.maxReadahead = n
+		return nil
+	}
+}
+
+// AsyncRead enables multiple outstanding read requests for the same
+// handle. Without this, there is at most one request in flight at a
+// time.
+func AsyncRead() MountOption {
+	return func(conf *mountConfig) error {
+		conf.initFlags |= InitAsyncRead
+		return nil
+	}
+}
+
+// WritebackCache enables the kernel to buffer writes before sending
+// them to the FUSE server. Without this, writethrough caching is
+// used.
+func WritebackCache() MountOption {
+	return func(conf *mountConfig) error {
+		conf.initFlags |= InitWritebackCache
+		return nil
+	}
+}
+
+// OSXFUSEPaths describes the paths used by an installed OSXFUSE
+// version. See OSXFUSELocationV3 for typical values.
+type OSXFUSEPaths struct {
+	// Prefix for the device file. At mount time, an incrementing
+	// number is suffixed until a free FUSE device is found.
+	DevicePrefix string
+	// Path of the load helper, used to load the kernel extension if
+	// no device files are found.
+	Load string
+	// Path of the mount helper, used for the actual mount operation.
+	Mount string
+	// Environment variable used to pass the path to the executable
+	// calling the mount helper.
+	DaemonVar string
+}
+
+// Default paths for OSXFUSE. See OSXFUSELocations.
+var (
+	OSXFUSELocationV3 = OSXFUSEPaths{
+		DevicePrefix: "/dev/osxfuse",
+		Load:         "/Library/Filesystems/osxfuse.fs/Contents/Resources/load_osxfuse",
+		Mount:        "/Library/Filesystems/osxfuse.fs/Contents/Resources/mount_osxfuse",
+		DaemonVar:    "MOUNT_OSXFUSE_DAEMON_PATH",
+	}
+	OSXFUSELocationV2 = OSXFUSEPaths{
+		DevicePrefix: "/dev/osxfuse",
+		Load:         "/Library/Filesystems/osxfusefs.fs/Support/load_osxfusefs",
+		Mount:        "/Library/Filesystems/osxfusefs.fs/Support/mount_osxfusefs",
+		DaemonVar:    "MOUNT_FUSEFS_DAEMON_PATH",
+	}
+)
+
+// OSXFUSELocations sets where to look for OSXFUSE files. The
+// arguments are all the possible locations. The previous locations
+// are replaced.
+//
+// Without this option, OSXFUSELocationV3 and OSXFUSELocationV2 are
+// used.
+//
+// OS X only. Others ignore this option.
+func OSXFUSELocations(paths ...OSXFUSEPaths) MountOption {
+	return func(conf *mountConfig) error {
+		if len(paths) == 0 {
+			return errors.New("must specify at least one location for OSXFUSELocations")
+		}
+		// replace previous values, but make a copy so there's no
+		// worries about caller mutating their slice
+		conf.osxfuseLocations = append(conf.osxfuseLocations[:0], paths...)
+		return nil
+	}
+}
+
+// AllowNonEmptyMount allows the mounting over a non-empty directory.
+//
+// The files in it will be shadowed by the freshly created mount. By
+// default these mounts are rejected to prevent accidental covering up
+// of data, which could for example prevent automatic backup.
+func AllowNonEmptyMount() MountOption {
+	return func(conf *mountConfig) error {
+		conf.options["nonempty"] = ""
+		return nil
+	}
+}
diff --git a/vendor/bazil.org/fuse/options_darwin.go b/vendor/bazil.org/fuse/options_darwin.go
new file mode 100644
index 000000000..faa9d78e7
--- /dev/null
+++ b/vendor/bazil.org/fuse/options_darwin.go
@@ -0,0 +1,35 @@
+package fuse
+
+func localVolume(conf *mountConfig) error {
+	conf.options["local"] = ""
+	return nil
+}
+
+func volumeName(name string) MountOption {
+	return func(conf *mountConfig) error {
+		conf.options["volname"] = name
+		return nil
+	}
+}
+
+func daemonTimeout(name string) MountOption {
+	return func(conf *mountConfig) error {
+		conf.options["daemon_timeout"] = name
+		return nil
+	}
+}
+
+func noAppleXattr(conf *mountConfig) error {
+	conf.options["noapplexattr"] = ""
+	return nil
+}
+
+func noAppleDouble(conf *mountConfig) error {
+	conf.options["noappledouble"] = ""
+	return nil
+}
+
+func exclCreate(conf *mountConfig) error {
+	conf.options["excl_create"] = ""
+	return nil
+}
diff --git a/vendor/bazil.org/fuse/options_freebsd.go b/vendor/bazil.org/fuse/options_freebsd.go
new file mode 100644
index 000000000..7c164b136
--- /dev/null
+++ b/vendor/bazil.org/fuse/options_freebsd.go
@@ -0,0 +1,28 @@
+package fuse
+
+func localVolume(conf *mountConfig) error {
+	return nil
+}
+
+func volumeName(name string) MountOption {
+	return dummyOption
+}
+
+func daemonTimeout(name string) MountOption {
+	return func(conf *mountConfig) error {
+		conf.options["timeout"] = name
+		return nil
+	}
+}
+
+func noAppleXattr(conf *mountConfig) error {
+	return nil
+}
+
+func noAppleDouble(conf *mountConfig) error {
+	return nil
+}
+
+func exclCreate(conf *mountConfig) error {
+	return nil
+}
diff --git a/vendor/bazil.org/fuse/options_linux.go b/vendor/bazil.org/fuse/options_linux.go
new file mode 100644
index 000000000..13f0896d5
--- /dev/null
+++ b/vendor/bazil.org/fuse/options_linux.go
@@ -0,0 +1,25 @@
+package fuse
+
+func localVolume(conf *mountConfig) error {
+	return nil
+}
+
+func volumeName(name string) MountOption {
+	return dummyOption
+}
+
+func daemonTimeout(name string) MountOption {
+	return dummyOption
+}
+
+func noAppleXattr(conf *mountConfig) error {
+	return nil
+}
+
+func noAppleDouble(conf *mountConfig) error {
+	return nil
+}
+
+func exclCreate(conf *mountConfig) error {
+	return nil
+}
diff --git a/vendor/bazil.org/fuse/protocol.go b/vendor/bazil.org/fuse/protocol.go
new file mode 100644
index 000000000..a77bbf72f
--- /dev/null
+++ b/vendor/bazil.org/fuse/protocol.go
@@ -0,0 +1,75 @@
+package fuse
+
+import (
+	"fmt"
+)
+
+// Protocol is a FUSE protocol version number.
+type Protocol struct {
+	Major uint32
+	Minor uint32
+}
+
+func (p Protocol) String() string {
+	return fmt.Sprintf("%d.%d", p.Major, p.Minor)
+}
+
+// LT returns whether a is less than b.
+func (a Protocol) LT(b Protocol) bool {
+	return a.Major < b.Major ||
+		(a.Major == b.Major && a.Minor < b.Minor)
+}
+
+// GE returns whether a is greater than or equal to b.
+func (a Protocol) GE(b Protocol) bool {
+	return a.Major > b.Major ||
+		(a.Major == b.Major && a.Minor >= b.Minor)
+}
+
+func (a Protocol) is79() bool {
+	return a.GE(Protocol{7, 9})
+}
+
+// HasAttrBlockSize returns whether Attr.BlockSize is respected by the
+// kernel.
+func (a Protocol) HasAttrBlockSize() bool {
+	return a.is79()
+}
+
+// HasReadWriteFlags returns whether ReadRequest/WriteRequest
+// fields Flags and FileFlags are valid.
+func (a Protocol) HasReadWriteFlags() bool {
+	return a.is79()
+}
+
+// HasGetattrFlags returns whether GetattrRequest field Flags is
+// valid.
+func (a Protocol) HasGetattrFlags() bool {
+	return a.is79()
+}
+
+func (a Protocol) is710() bool {
+	return a.GE(Protocol{7, 10})
+}
+
+// HasOpenNonSeekable returns whether OpenResponse field Flags flag
+// OpenNonSeekable is supported.
+func (a Protocol) HasOpenNonSeekable() bool {
+	return a.is710()
+}
+
+func (a Protocol) is712() bool {
+	return a.GE(Protocol{7, 12})
+}
+
+// HasUmask returns whether CreateRequest/MkdirRequest/MknodRequest
+// field Umask is valid.
+func (a Protocol) HasUmask() bool {
+	return a.is712()
+}
+
+// HasInvalidate returns whether InvalidateNode/InvalidateEntry are
+// supported.
+func (a Protocol) HasInvalidate() bool {
+	return a.is712()
+}
diff --git a/vendor/bazil.org/fuse/unmount.go b/vendor/bazil.org/fuse/unmount.go
new file mode 100644
index 000000000..ffe3f155c
--- /dev/null
+++ b/vendor/bazil.org/fuse/unmount.go
@@ -0,0 +1,6 @@
+package fuse
+
+// Unmount tries to unmount the filesystem mounted at dir.
+func Unmount(dir string) error {
+	return unmount(dir)
+}
diff --git a/vendor/bazil.org/fuse/unmount_linux.go b/vendor/bazil.org/fuse/unmount_linux.go
new file mode 100644
index 000000000..088f0cfee
--- /dev/null
+++ b/vendor/bazil.org/fuse/unmount_linux.go
@@ -0,0 +1,21 @@
+package fuse
+
+import (
+	"bytes"
+	"errors"
+	"os/exec"
+)
+
+func unmount(dir string) error {
+	cmd := exec.Command("fusermount", "-u", dir)
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		if len(output) > 0 {
+			output = bytes.TrimRight(output, "\n")
+			msg := err.Error() + ": " + string(output)
+			err = errors.New(msg)
+		}
+		return err
+	}
+	return nil
+}
diff --git a/vendor/bazil.org/fuse/unmount_std.go b/vendor/bazil.org/fuse/unmount_std.go
new file mode 100644
index 000000000..d6efe276f
--- /dev/null
+++ b/vendor/bazil.org/fuse/unmount_std.go
@@ -0,0 +1,17 @@
+// +build !linux
+
+package fuse
+
+import (
+	"os"
+	"syscall"
+)
+
+func unmount(dir string) error {
+	err := syscall.Unmount(dir, 0)
+	if err != nil {
+		err = &os.PathError{Op: "unmount", Path: dir, Err: err}
+		return err
+	}
+	return nil
+}
diff --git a/vendor/golang.org/x/net/context/context.go b/vendor/golang.org/x/net/context/context.go
new file mode 100644
index 000000000..a3c021d3f
--- /dev/null
+++ b/vendor/golang.org/x/net/context/context.go
@@ -0,0 +1,56 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package context defines the Context type, which carries deadlines,
+// cancelation signals, and other request-scoped values across API boundaries
+// and between processes.
+// As of Go 1.7 this package is available in the standard library under the
+// name context.  https://golang.org/pkg/context.
+//
+// Incoming requests to a server should create a Context, and outgoing calls to
+// servers should accept a Context. The chain of function calls between must
+// propagate the Context, optionally replacing it with a modified copy created
+// using WithDeadline, WithTimeout, WithCancel, or WithValue.
+//
+// Programs that use Contexts should follow these rules to keep interfaces
+// consistent across packages and enable static analysis tools to check context
+// propagation:
+//
+// Do not store Contexts inside a struct type; instead, pass a Context
+// explicitly to each function that needs it. The Context should be the first
+// parameter, typically named ctx:
+//
+// 	func DoSomething(ctx context.Context, arg Arg) error {
+// 		// ... use ctx ...
+// 	}
+//
+// Do not pass a nil Context, even if a function permits it. Pass context.TODO
+// if you are unsure about which Context to use.
+//
+// Use context Values only for request-scoped data that transits processes and
+// APIs, not for passing optional parameters to functions.
+//
+// The same Context may be passed to functions running in different goroutines;
+// Contexts are safe for simultaneous use by multiple goroutines.
+//
+// See http://blog.golang.org/context for example code for a server that uses
+// Contexts.
+package context // import "golang.org/x/net/context"
+
+// Background returns a non-nil, empty Context. It is never canceled, has no
+// values, and has no deadline. It is typically used by the main function,
+// initialization, and tests, and as the top-level Context for incoming
+// requests.
+func Background() Context {
+	return background
+}
+
+// TODO returns a non-nil, empty Context. Code should use context.TODO when
+// it's unclear which Context to use or it is not yet available (because the
+// surrounding function has not yet been extended to accept a Context
+// parameter).  TODO is recognized by static analysis tools that determine
+// whether Contexts are propagated correctly in a program.
+func TODO() Context {
+	return todo
+}
diff --git a/vendor/golang.org/x/net/context/go17.go b/vendor/golang.org/x/net/context/go17.go
new file mode 100644
index 000000000..d20f52b7d
--- /dev/null
+++ b/vendor/golang.org/x/net/context/go17.go
@@ -0,0 +1,72 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.7
+
+package context
+
+import (
+	"context" // standard library's context, as of Go 1.7
+	"time"
+)
+
+var (
+	todo       = context.TODO()
+	background = context.Background()
+)
+
+// Canceled is the error returned by Context.Err when the context is canceled.
+var Canceled = context.Canceled
+
+// DeadlineExceeded is the error returned by Context.Err when the context's
+// deadline passes.
+var DeadlineExceeded = context.DeadlineExceeded
+
+// WithCancel returns a copy of parent with a new Done channel. The returned
+// context's Done channel is closed when the returned cancel function is called
+// or when the parent context's Done channel is closed, whichever happens first.
+//
+// Canceling this context releases resources associated with it, so code should
+// call cancel as soon as the operations running in this Context complete.
+func WithCancel(parent Context) (ctx Context, cancel CancelFunc) {
+	ctx, f := context.WithCancel(parent)
+	return ctx, CancelFunc(f)
+}
+
+// WithDeadline returns a copy of the parent context with the deadline adjusted
+// to be no later than d. If the parent's deadline is already earlier than d,
+// WithDeadline(parent, d) is semantically equivalent to parent. The returned
+// context's Done channel is closed when the deadline expires, when the returned
+// cancel function is called, or when the parent context's Done channel is
+// closed, whichever happens first.
+//
+// Canceling this context releases resources associated with it, so code should
+// call cancel as soon as the operations running in this Context complete.
+func WithDeadline(parent Context, deadline time.Time) (Context, CancelFunc) {
+	ctx, f := context.WithDeadline(parent, deadline)
+	return ctx, CancelFunc(f)
+}
+
+// WithTimeout returns WithDeadline(parent, time.Now().Add(timeout)).
+//
+// Canceling this context releases resources associated with it, so code should
+// call cancel as soon as the operations running in this Context complete:
+//
+// 	func slowOperationWithTimeout(ctx context.Context) (Result, error) {
+// 		ctx, cancel := context.WithTimeout(ctx, 100*time.Millisecond)
+// 		defer cancel()  // releases resources if slowOperation completes before timeout elapses
+// 		return slowOperation(ctx)
+// 	}
+func WithTimeout(parent Context, timeout time.Duration) (Context, CancelFunc) {
+	return WithDeadline(parent, time.Now().Add(timeout))
+}
+
+// WithValue returns a copy of parent in which the value associated with key is
+// val.
+//
+// Use context Values only for request-scoped data that transits processes and
+// APIs, not for passing optional parameters to functions.
+func WithValue(parent Context, key interface{}, val interface{}) Context {
+	return context.WithValue(parent, key, val)
+}
diff --git a/vendor/golang.org/x/net/context/go19.go b/vendor/golang.org/x/net/context/go19.go
new file mode 100644
index 000000000..d88bd1db1
--- /dev/null
+++ b/vendor/golang.org/x/net/context/go19.go
@@ -0,0 +1,20 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.9
+
+package context
+
+import "context" // standard library's context, as of Go 1.7
+
+// A Context carries a deadline, a cancelation signal, and other values across
+// API boundaries.
+//
+// Context's methods may be called by multiple goroutines simultaneously.
+type Context = context.Context
+
+// A CancelFunc tells an operation to abandon its work.
+// A CancelFunc does not wait for the work to stop.
+// After the first call, subsequent calls to a CancelFunc do nothing.
+type CancelFunc = context.CancelFunc
diff --git a/vendor/golang.org/x/net/context/pre_go17.go b/vendor/golang.org/x/net/context/pre_go17.go
new file mode 100644
index 000000000..0f35592df
--- /dev/null
+++ b/vendor/golang.org/x/net/context/pre_go17.go
@@ -0,0 +1,300 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.7
+
+package context
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+)
+
+// An emptyCtx is never canceled, has no values, and has no deadline. It is not
+// struct{}, since vars of this type must have distinct addresses.
+type emptyCtx int
+
+func (*emptyCtx) Deadline() (deadline time.Time, ok bool) {
+	return
+}
+
+func (*emptyCtx) Done() <-chan struct{} {
+	return nil
+}
+
+func (*emptyCtx) Err() error {
+	return nil
+}
+
+func (*emptyCtx) Value(key interface{}) interface{} {
+	return nil
+}
+
+func (e *emptyCtx) String() string {
+	switch e {
+	case background:
+		return "context.Background"
+	case todo:
+		return "context.TODO"
+	}
+	return "unknown empty Context"
+}
+
+var (
+	background = new(emptyCtx)
+	todo       = new(emptyCtx)
+)
+
+// Canceled is the error returned by Context.Err when the context is canceled.
+var Canceled = errors.New("context canceled")
+
+// DeadlineExceeded is the error returned by Context.Err when the context's
+// deadline passes.
+var DeadlineExceeded = errors.New("context deadline exceeded")
+
+// WithCancel returns a copy of parent with a new Done channel. The returned
+// context's Done channel is closed when the returned cancel function is called
+// or when the parent context's Done channel is closed, whichever happens first.
+//
+// Canceling this context releases resources associated with it, so code should
+// call cancel as soon as the operations running in this Context complete.
+func WithCancel(parent Context) (ctx Context, cancel CancelFunc) {
+	c := newCancelCtx(parent)
+	propagateCancel(parent, c)
+	return c, func() { c.cancel(true, Canceled) }
+}
+
+// newCancelCtx returns an initialized cancelCtx.
+func newCancelCtx(parent Context) *cancelCtx {
+	return &cancelCtx{
+		Context: parent,
+		done:    make(chan struct{}),
+	}
+}
+
+// propagateCancel arranges for child to be canceled when parent is.
+func propagateCancel(parent Context, child canceler) {
+	if parent.Done() == nil {
+		return // parent is never canceled
+	}
+	if p, ok := parentCancelCtx(parent); ok {
+		p.mu.Lock()
+		if p.err != nil {
+			// parent has already been canceled
+			child.cancel(false, p.err)
+		} else {
+			if p.children == nil {
+				p.children = make(map[canceler]bool)
+			}
+			p.children[child] = true
+		}
+		p.mu.Unlock()
+	} else {
+		go func() {
+			select {
+			case <-parent.Done():
+				child.cancel(false, parent.Err())
+			case <-child.Done():
+			}
+		}()
+	}
+}
+
+// parentCancelCtx follows a chain of parent references until it finds a
+// *cancelCtx. This function understands how each of the concrete types in this
+// package represents its parent.
+func parentCancelCtx(parent Context) (*cancelCtx, bool) {
+	for {
+		switch c := parent.(type) {
+		case *cancelCtx:
+			return c, true
+		case *timerCtx:
+			return c.cancelCtx, true
+		case *valueCtx:
+			parent = c.Context
+		default:
+			return nil, false
+		}
+	}
+}
+
+// removeChild removes a context from its parent.
+func removeChild(parent Context, child canceler) {
+	p, ok := parentCancelCtx(parent)
+	if !ok {
+		return
+	}
+	p.mu.Lock()
+	if p.children != nil {
+		delete(p.children, child)
+	}
+	p.mu.Unlock()
+}
+
+// A canceler is a context type that can be canceled directly. The
+// implementations are *cancelCtx and *timerCtx.
+type canceler interface {
+	cancel(removeFromParent bool, err error)
+	Done() <-chan struct{}
+}
+
+// A cancelCtx can be canceled. When canceled, it also cancels any children
+// that implement canceler.
+type cancelCtx struct {
+	Context
+
+	done chan struct{} // closed by the first cancel call.
+
+	mu       sync.Mutex
+	children map[canceler]bool // set to nil by the first cancel call
+	err      error             // set to non-nil by the first cancel call
+}
+
+func (c *cancelCtx) Done() <-chan struct{} {
+	return c.done
+}
+
+func (c *cancelCtx) Err() error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return c.err
+}
+
+func (c *cancelCtx) String() string {
+	return fmt.Sprintf("%v.WithCancel", c.Context)
+}
+
+// cancel closes c.done, cancels each of c's children, and, if
+// removeFromParent is true, removes c from its parent's children.
+func (c *cancelCtx) cancel(removeFromParent bool, err error) {
+	if err == nil {
+		panic("context: internal error: missing cancel error")
+	}
+	c.mu.Lock()
+	if c.err != nil {
+		c.mu.Unlock()
+		return // already canceled
+	}
+	c.err = err
+	close(c.done)
+	for child := range c.children {
+		// NOTE: acquiring the child's lock while holding parent's lock.
+		child.cancel(false, err)
+	}
+	c.children = nil
+	c.mu.Unlock()
+
+	if removeFromParent {
+		removeChild(c.Context, c)
+	}
+}
+
+// WithDeadline returns a copy of the parent context with the deadline adjusted
+// to be no later than d. If the parent's deadline is already earlier than d,
+// WithDeadline(parent, d) is semantically equivalent to parent. The returned
+// context's Done channel is closed when the deadline expires, when the returned
+// cancel function is called, or when the parent context's Done channel is
+// closed, whichever happens first.
+//
+// Canceling this context releases resources associated with it, so code should
+// call cancel as soon as the operations running in this Context complete.
+func WithDeadline(parent Context, deadline time.Time) (Context, CancelFunc) {
+	if cur, ok := parent.Deadline(); ok && cur.Before(deadline) {
+		// The current deadline is already sooner than the new one.
+		return WithCancel(parent)
+	}
+	c := &timerCtx{
+		cancelCtx: newCancelCtx(parent),
+		deadline:  deadline,
+	}
+	propagateCancel(parent, c)
+	d := deadline.Sub(time.Now())
+	if d <= 0 {
+		c.cancel(true, DeadlineExceeded) // deadline has already passed
+		return c, func() { c.cancel(true, Canceled) }
+	}
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.err == nil {
+		c.timer = time.AfterFunc(d, func() {
+			c.cancel(true, DeadlineExceeded)
+		})
+	}
+	return c, func() { c.cancel(true, Canceled) }
+}
+
+// A timerCtx carries a timer and a deadline. It embeds a cancelCtx to
+// implement Done and Err. It implements cancel by stopping its timer then
+// delegating to cancelCtx.cancel.
+type timerCtx struct {
+	*cancelCtx
+	timer *time.Timer // Under cancelCtx.mu.
+
+	deadline time.Time
+}
+
+func (c *timerCtx) Deadline() (deadline time.Time, ok bool) {
+	return c.deadline, true
+}
+
+func (c *timerCtx) String() string {
+	return fmt.Sprintf("%v.WithDeadline(%s [%s])", c.cancelCtx.Context, c.deadline, c.deadline.Sub(time.Now()))
+}
+
+func (c *timerCtx) cancel(removeFromParent bool, err error) {
+	c.cancelCtx.cancel(false, err)
+	if removeFromParent {
+		// Remove this timerCtx from its parent cancelCtx's children.
+		removeChild(c.cancelCtx.Context, c)
+	}
+	c.mu.Lock()
+	if c.timer != nil {
+		c.timer.Stop()
+		c.timer = nil
+	}
+	c.mu.Unlock()
+}
+
+// WithTimeout returns WithDeadline(parent, time.Now().Add(timeout)).
+//
+// Canceling this context releases resources associated with it, so code should
+// call cancel as soon as the operations running in this Context complete:
+//
+// 	func slowOperationWithTimeout(ctx context.Context) (Result, error) {
+// 		ctx, cancel := context.WithTimeout(ctx, 100*time.Millisecond)
+// 		defer cancel()  // releases resources if slowOperation completes before timeout elapses
+// 		return slowOperation(ctx)
+// 	}
+func WithTimeout(parent Context, timeout time.Duration) (Context, CancelFunc) {
+	return WithDeadline(parent, time.Now().Add(timeout))
+}
+
+// WithValue returns a copy of parent in which the value associated with key is
+// val.
+//
+// Use context Values only for request-scoped data that transits processes and
+// APIs, not for passing optional parameters to functions.
+func WithValue(parent Context, key interface{}, val interface{}) Context {
+	return &valueCtx{parent, key, val}
+}
+
+// A valueCtx carries a key-value pair. It implements Value for that key and
+// delegates all other calls to the embedded Context.
+type valueCtx struct {
+	Context
+	key, val interface{}
+}
+
+func (c *valueCtx) String() string {
+	return fmt.Sprintf("%v.WithValue(%#v, %#v)", c.Context, c.key, c.val)
+}
+
+func (c *valueCtx) Value(key interface{}) interface{} {
+	if c.key == key {
+		return c.val
+	}
+	return c.Context.Value(key)
+}
diff --git a/vendor/golang.org/x/net/context/pre_go19.go b/vendor/golang.org/x/net/context/pre_go19.go
new file mode 100644
index 000000000..b105f80be
--- /dev/null
+++ b/vendor/golang.org/x/net/context/pre_go19.go
@@ -0,0 +1,109 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.9
+
+package context
+
+import "time"
+
+// A Context carries a deadline, a cancelation signal, and other values across
+// API boundaries.
+//
+// Context's methods may be called by multiple goroutines simultaneously.
+type Context interface {
+	// Deadline returns the time when work done on behalf of this context
+	// should be canceled. Deadline returns ok==false when no deadline is
+	// set. Successive calls to Deadline return the same results.
+	Deadline() (deadline time.Time, ok bool)
+
+	// Done returns a channel that's closed when work done on behalf of this
+	// context should be canceled. Done may return nil if this context can
+	// never be canceled. Successive calls to Done return the same value.
+	//
+	// WithCancel arranges for Done to be closed when cancel is called;
+	// WithDeadline arranges for Done to be closed when the deadline
+	// expires; WithTimeout arranges for Done to be closed when the timeout
+	// elapses.
+	//
+	// Done is provided for use in select statements:
+	//
+	//  // Stream generates values with DoSomething and sends them to out
+	//  // until DoSomething returns an error or ctx.Done is closed.
+	//  func Stream(ctx context.Context, out chan<- Value) error {
+	//  	for {
+	//  		v, err := DoSomething(ctx)
+	//  		if err != nil {
+	//  			return err
+	//  		}
+	//  		select {
+	//  		case <-ctx.Done():
+	//  			return ctx.Err()
+	//  		case out <- v:
+	//  		}
+	//  	}
+	//  }
+	//
+	// See http://blog.golang.org/pipelines for more examples of how to use
+	// a Done channel for cancelation.
+	Done() <-chan struct{}
+
+	// Err returns a non-nil error value after Done is closed. Err returns
+	// Canceled if the context was canceled or DeadlineExceeded if the
+	// context's deadline passed. No other values for Err are defined.
+	// After Done is closed, successive calls to Err return the same value.
+	Err() error
+
+	// Value returns the value associated with this context for key, or nil
+	// if no value is associated with key. Successive calls to Value with
+	// the same key returns the same result.
+	//
+	// Use context values only for request-scoped data that transits
+	// processes and API boundaries, not for passing optional parameters to
+	// functions.
+	//
+	// A key identifies a specific value in a Context. Functions that wish
+	// to store values in Context typically allocate a key in a global
+	// variable then use that key as the argument to context.WithValue and
+	// Context.Value. A key can be any type that supports equality;
+	// packages should define keys as an unexported type to avoid
+	// collisions.
+	//
+	// Packages that define a Context key should provide type-safe accessors
+	// for the values stores using that key:
+	//
+	// 	// Package user defines a User type that's stored in Contexts.
+	// 	package user
+	//
+	// 	import "golang.org/x/net/context"
+	//
+	// 	// User is the type of value stored in the Contexts.
+	// 	type User struct {...}
+	//
+	// 	// key is an unexported type for keys defined in this package.
+	// 	// This prevents collisions with keys defined in other packages.
+	// 	type key int
+	//
+	// 	// userKey is the key for user.User values in Contexts. It is
+	// 	// unexported; clients use user.NewContext and user.FromContext
+	// 	// instead of using this key directly.
+	// 	var userKey key = 0
+	//
+	// 	// NewContext returns a new Context that carries value u.
+	// 	func NewContext(ctx context.Context, u *User) context.Context {
+	// 		return context.WithValue(ctx, userKey, u)
+	// 	}
+	//
+	// 	// FromContext returns the User value stored in ctx, if any.
+	// 	func FromContext(ctx context.Context) (*User, bool) {
+	// 		u, ok := ctx.Value(userKey).(*User)
+	// 		return u, ok
+	// 	}
+	Value(key interface{}) interface{}
+}
+
+// A CancelFunc tells an operation to abandon its work.
+// A CancelFunc does not wait for the work to stop.
+// After the first call, subsequent calls to a CancelFunc do nothing.
+type CancelFunc func()
diff --git a/worker/db.go b/worker/db.go
index 1c95d9763..ba2c7289f 100644
--- a/worker/db.go
+++ b/worker/db.go
@@ -18,27 +18,20 @@ package worker
 
 import (
 	"context"
-	"database/sql"
-	"io"
 	"os"
 	"path/filepath"
-	"runtime/trace"
-	"strings"
+	//"runtime/trace"
 	"sync"
 	"time"
 
-	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
 	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
 	"github.com/CovenantSQL/CovenantSQL/kayak"
 	kt "github.com/CovenantSQL/CovenantSQL/kayak/types"
 	kl "github.com/CovenantSQL/CovenantSQL/kayak/wal"
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/sqlchain"
-	"github.com/CovenantSQL/CovenantSQL/sqlchain/storage"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
-	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
-	"github.com/CovenantSQL/sqlparser"
+	"github.com/CovenantSQL/CovenantSQL/storage"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/pkg/errors"
 )
 
@@ -66,7 +59,6 @@ const (
 type Database struct {
 	cfg            *DBConfig
 	dbID           proto.DatabaseID
-	storage        *storage.Storage
 	kayakWal       *kl.LevelDBWal
 	kayakRuntime   *kayak.Runtime
 	kayakConfig    *kt.RuntimeConfig
@@ -78,7 +70,7 @@ type Database struct {
 }
 
 // NewDatabase create a single database instance using config.
-func NewDatabase(cfg *DBConfig, peers *proto.Peers, genesisBlock *ct.Block) (db *Database, err error) {
+func NewDatabase(cfg *DBConfig, peers *proto.Peers, genesisBlock *types.Block) (db *Database, err error) {
 	// ensure dir exists
 	if err = os.MkdirAll(cfg.DataDir, 0755); err != nil {
 		return
@@ -109,11 +101,6 @@ func NewDatabase(cfg *DBConfig, peers *proto.Peers, genesisBlock *ct.Block) (db
 			if db.chain != nil {
 				db.chain.Stop()
 			}
-
-			// close storage
-			if db.storage != nil {
-				db.storage.Close()
-			}
 		}
 	}()
 
@@ -128,10 +115,6 @@ func NewDatabase(cfg *DBConfig, peers *proto.Peers, genesisBlock *ct.Block) (db
 		storageDSN.AddParam("_crypto_key", cfg.EncryptionKey)
 	}
 
-	if db.storage, err = storage.New(storageDSN.Format()); err != nil {
-		return
-	}
-
 	// init chain
 	chainFile := filepath.Join(cfg.DataDir, SQLChainFileName)
 	if db.nodeID, err = kms.GetLocalNodeID(); err != nil {
@@ -140,10 +123,11 @@ func NewDatabase(cfg *DBConfig, peers *proto.Peers, genesisBlock *ct.Block) (db
 
 	// TODO(xq262144): make sqlchain config use of global config object
 	chainCfg := &sqlchain.Config{
-		DatabaseID: cfg.DatabaseID,
-		DataFile:   chainFile,
-		Genesis:    genesisBlock,
-		Peers:      peers,
+		DatabaseID:      cfg.DatabaseID,
+		ChainFilePrefix: chainFile,
+		DataFile:        storageDSN.Format(),
+		Genesis:         genesisBlock,
+		Peers:           peers,
 
 		// TODO(xq262144): should refactor server/node definition to conf/proto package
 		// currently sqlchain package only use Server.ID as node id
@@ -209,16 +193,16 @@ func (db *Database) UpdatePeers(peers *proto.Peers) (err error) {
 }
 
 // Query defines database query interface.
-func (db *Database) Query(request *wt.Request) (response *wt.Response, err error) {
+func (db *Database) Query(request *types.Request) (response *types.Response, err error) {
 	// Just need to verify signature in db.saveAck
 	//if err = request.Verify(); err != nil {
 	//	return
 	//}
 
 	switch request.Header.QueryType {
-	case wt.ReadQuery:
-		return db.readQuery(request)
-	case wt.WriteQuery:
+	case types.ReadQuery:
+		return db.chain.Query(request)
+	case types.WriteQuery:
 		return db.writeQuery(request)
 	default:
 		// TODO(xq262144): verbose errors with custom error structure
@@ -227,7 +211,7 @@ func (db *Database) Query(request *wt.Request) (response *wt.Response, err error
 }
 
 // Ack defines client response ack interface.
-func (db *Database) Ack(ack *wt.Ack) (err error) {
+func (db *Database) Ack(ack *types.Ack) (err error) {
 	// Just need to verify signature in db.saveAck
 	//if err = ack.Verify(); err != nil {
 	//	return
@@ -260,13 +244,6 @@ func (db *Database) Shutdown() (err error) {
 		}
 	}
 
-	if db.storage != nil {
-		// stop storage
-		if err = db.storage.Close(); err != nil {
-			return
-		}
-	}
-
 	if db.connSeqEvictCh != nil {
 		// stop connection sequence evictions
 		select {
@@ -294,11 +271,11 @@ func (db *Database) Destroy() (err error) {
 	return
 }
 
-func (db *Database) writeQuery(request *wt.Request) (response *wt.Response, err error) {
-	ctx := context.Background()
-	ctx, task := trace.NewTask(ctx, "writeQuery")
-	defer task.End()
-	defer trace.StartRegion(ctx, "writeQueryRegion").End()
+func (db *Database) writeQuery(request *types.Request) (response *types.Response, err error) {
+	//ctx := context.Background()
+	//ctx, task := trace.NewTask(ctx, "writeQuery")
+	//defer task.End()
+	//defer trace.StartRegion(ctx, "writeQueryRegion").End()
 
 	// check database size first, wal/kayak/chain database size is not included
 	if db.cfg.SpaceLimit > 0 {
@@ -318,174 +295,25 @@ func (db *Database) writeQuery(request *wt.Request) (response *wt.Response, err
 	}
 
 	// call kayak runtime Process
-	var logOffset uint64
 	var result interface{}
-	result, logOffset, err = db.kayakRuntime.Apply(context.Background(), request)
-
-	if err != nil {
-		return
-	}
-
-	// get affected rows and last insert id
-	var affectedRows, lastInsertID int64
-
-	if execResult, ok := result.(storage.ExecResult); ok {
-		affectedRows = execResult.RowsAffected
-		lastInsertID = execResult.LastInsertID
-	}
-
-	return db.buildQueryResponse(request, logOffset, []string{}, []string{}, [][]interface{}{}, lastInsertID, affectedRows)
-}
-
-func (db *Database) readQuery(request *wt.Request) (response *wt.Response, err error) {
-	// call storage query directly
-	// TODO(xq262144): add timeout logic basic of client options
-	var columns, types []string
-	var data [][]interface{}
-	var queries []storage.Query
-
-	// sanitize dangerous queries
-	if queries, err = convertAndSanitizeQuery(request.Payload.Queries); err != nil {
-		return
-	}
-
-	columns, types, data, err = db.storage.Query(context.Background(), queries)
-	if err != nil {
-		return
-	}
-
-	return db.buildQueryResponse(request, 0, columns, types, data, 0, 0)
-}
-
-func (db *Database) getLog(index uint64) (data interface{}, err error) {
-	var l *kt.Log
-	if l, err = db.kayakWal.Get(index); err != nil || l == nil {
-		err = errors.Wrap(err, "get log from kayak pool failed")
-		return
-	}
-
-	// decode log
-	data, err = db.DecodePayload(l.Data)
-
-	return
-}
-
-func (db *Database) buildQueryResponse(request *wt.Request, offset uint64,
-	columns []string, types []string, data [][]interface{}, lastInsertID int64, affectedRows int64) (response *wt.Response, err error) {
-	// build response
-	response = new(wt.Response)
-	response.Header.Request = request.Header
-	if response.Header.NodeID, err = kms.GetLocalNodeID(); err != nil {
+	if result, _, err = db.kayakRuntime.Apply(context.Background(), request); err != nil {
+		err = errors.Wrap(err, "apply failed")
 		return
 	}
-	response.Header.LogOffset = offset
-	response.Header.Timestamp = getLocalTime()
-	response.Header.RowCount = uint64(len(data))
-	response.Header.LastInsertID = lastInsertID
-	response.Header.AffectedRows = affectedRows
-
-	// set payload
-	response.Payload.Columns = columns
-	response.Payload.DeclTypes = types
-	response.Payload.Rows = make([]wt.ResponseRow, len(data))
-
-	for i, d := range data {
-		response.Payload.Rows[i].Values = d
-	}
 
-	// sign fields
-	var privateKey *asymmetric.PrivateKey
-	if privateKey, err = getLocalPrivateKey(); err != nil {
-		return
-	}
-	if err = response.Sign(privateKey); err != nil {
+	var ok bool
+	if response, ok = (result).(*types.Response); !ok {
+		err = errors.Wrap(err, "invalid response type")
 		return
 	}
 
-	// record response for future ack process
-	err = db.saveResponse(&response.Header)
 	return
 }
 
-func (db *Database) saveResponse(respHeader *wt.SignedResponseHeader) (err error) {
-	return db.chain.VerifyAndPushResponsedQuery(respHeader)
-}
-
-func (db *Database) saveAck(ackHeader *wt.SignedAckHeader) (err error) {
+func (db *Database) saveAck(ackHeader *types.SignedAckHeader) (err error) {
 	return db.chain.VerifyAndPushAckedQuery(ackHeader)
 }
 
 func getLocalTime() time.Time {
 	return time.Now().UTC()
 }
-
-func getLocalPrivateKey() (privateKey *asymmetric.PrivateKey, err error) {
-	return kms.GetLocalPrivateKey()
-}
-
-func convertAndSanitizeQuery(inQuery []wt.Query) (outQuery []storage.Query, err error) {
-	outQuery = make([]storage.Query, len(inQuery))
-	for i, q := range inQuery {
-		tokenizer := sqlparser.NewStringTokenizer(q.Pattern)
-		var stmt sqlparser.Statement
-		var lastPos int
-		var query string
-		var originalQueries []string
-
-		for {
-			stmt, err = sqlparser.ParseNext(tokenizer)
-
-			if err != nil && err != io.EOF {
-				return
-			}
-
-			if err == io.EOF {
-				err = nil
-				break
-			}
-
-			query = q.Pattern[lastPos : tokenizer.Position-1]
-			lastPos = tokenizer.Position + 1
-
-			// translate show statement
-			if showStmt, ok := stmt.(*sqlparser.Show); ok {
-				origQuery := query
-
-				switch showStmt.Type {
-				case "table":
-					if showStmt.ShowCreate {
-						query = "SELECT sql FROM sqlite_master WHERE type = \"table\" AND tbl_name = \"" +
-							showStmt.OnTable.Name.String() + "\""
-					} else {
-						query = "PRAGMA table_info(" + showStmt.OnTable.Name.String() + ")"
-					}
-				case "index":
-					query = "SELECT name FROM sqlite_master WHERE type = \"index\" AND tbl_name = \"" +
-						showStmt.OnTable.Name.String() + "\""
-				case "tables":
-					query = "SELECT name FROM sqlite_master WHERE type = \"table\""
-				}
-
-				log.WithFields(log.Fields{
-					"from": origQuery,
-					"to":   query,
-				}).Debug("query translated")
-			}
-
-			originalQueries = append(originalQueries, query)
-		}
-
-		// covert args
-		var args []sql.NamedArg
-
-		for _, v := range q.Args {
-			args = append(args, sql.Named(v.Name, v.Value))
-		}
-
-		outQuery[i] = storage.Query{
-			Pattern: strings.Join(originalQueries, "; "),
-			Args:    args,
-		}
-	}
-	return
-}
diff --git a/worker/db_storage.go b/worker/db_storage.go
index 6c7ca1ac3..b56f6bbee 100644
--- a/worker/db_storage.go
+++ b/worker/db_storage.go
@@ -19,11 +19,9 @@ package worker
 import (
 	"bytes"
 	"container/list"
-	"context"
 
-	"github.com/CovenantSQL/CovenantSQL/sqlchain/storage"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 	"github.com/pkg/errors"
 )
 
@@ -44,7 +42,7 @@ func (db *Database) EncodePayload(request interface{}) (data []byte, err error)
 
 // DecodePayload implements kayak.types.Handler.DecodePayload.
 func (db *Database) DecodePayload(data []byte) (request interface{}, err error) {
-	var req *wt.Request
+	var req *types.Request
 
 	if err = utils.DecodeMsgPack(data, &req); err != nil {
 		err = errors.Wrap(err, "decode request failed")
@@ -58,9 +56,9 @@ func (db *Database) DecodePayload(data []byte) (request interface{}, err error)
 
 // Check implements kayak.types.Handler.Check.
 func (db *Database) Check(rawReq interface{}) (err error) {
-	var req *wt.Request
+	var req *types.Request
 	var ok bool
-	if req, ok = rawReq.(*wt.Request); !ok || req == nil {
+	if req, ok = rawReq.(*types.Request); !ok || req == nil {
 		err = errors.Wrap(ErrInvalidRequest, "invalid request payload")
 		return
 	}
@@ -91,24 +89,18 @@ func (db *Database) Check(rawReq interface{}) (err error) {
 	return
 }
 
-// Commit implements kayak.types.Handler.Commmit.
+// Commit implements kayak.types.Handler.Commit.
 func (db *Database) Commit(rawReq interface{}) (result interface{}, err error) {
 	// convert query and check syntax
-	var req *wt.Request
+	var req *types.Request
 	var ok bool
-	if req, ok = rawReq.(*wt.Request); !ok || req == nil {
+	if req, ok = rawReq.(*types.Request); !ok || req == nil {
 		err = errors.Wrap(ErrInvalidRequest, "invalid request payload")
 		return
 	}
 
-	var queries []storage.Query
-	if queries, err = convertAndSanitizeQuery(req.Payload.Queries); err != nil {
-		// return original parser error
-		return
-	}
-
 	// execute
-	return db.storage.Exec(context.Background(), queries)
+	return db.chain.Query(req)
 }
 
 func (db *Database) recordSequence(connID uint64, seqNo uint64) {
diff --git a/worker/db_test.go b/worker/db_test.go
index 782dd1cde..36561d5bc 100644
--- a/worker/db_test.go
+++ b/worker/db_test.go
@@ -29,7 +29,6 @@ import (
 	"testing"
 	"time"
 
-	bp "github.com/CovenantSQL/CovenantSQL/blockproducer"
 	"github.com/CovenantSQL/CovenantSQL/conf"
 	"github.com/CovenantSQL/CovenantSQL/consistent"
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
@@ -40,10 +39,9 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
 	"github.com/CovenantSQL/CovenantSQL/sqlchain"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 	"github.com/fortytw2/leaktest"
 	. "github.com/smartystreets/goconvey/convey"
 )
@@ -88,7 +86,7 @@ func TestSingleDatabase(t *testing.T) {
 		}
 
 		// create genesis block
-		var block *ct.Block
+		var block *types.Block
 		block, err = createRandomBlock(rootHash, true)
 		So(err, ShouldBeNil)
 
@@ -99,9 +97,9 @@ func TestSingleDatabase(t *testing.T) {
 
 		Convey("test query rewrite", func() {
 			// test query rewrite
-			var writeQuery *wt.Request
-			var res *wt.Response
-			writeQuery, err = buildQuery(wt.WriteQuery, 1, 1, []string{
+			var writeQuery *types.Request
+			var res *types.Response
+			writeQuery, err = buildQuery(types.WriteQuery, 1, 1, []string{
 				"create table test (col1 int, col2 string)",
 				"create index test_index on test (col1)",
 			})
@@ -113,8 +111,8 @@ func TestSingleDatabase(t *testing.T) {
 			So(err, ShouldBeNil)
 
 			// test show tables query
-			var readQuery *wt.Request
-			readQuery, err = buildQuery(wt.ReadQuery, 1, 2, []string{
+			var readQuery *types.Request
+			readQuery, err = buildQuery(types.ReadQuery, 1, 2, []string{
 				"show tables",
 			})
 			So(err, ShouldBeNil)
@@ -130,7 +128,7 @@ func TestSingleDatabase(t *testing.T) {
 			So(res.Payload.Rows[0].Values[0], ShouldResemble, []byte("test"))
 
 			// test show full tables query
-			readQuery, err = buildQuery(wt.ReadQuery, 1, 3, []string{
+			readQuery, err = buildQuery(types.ReadQuery, 1, 3, []string{
 				"show full tables",
 			})
 			So(err, ShouldBeNil)
@@ -146,7 +144,7 @@ func TestSingleDatabase(t *testing.T) {
 			So(res.Payload.Rows[0].Values[0], ShouldResemble, []byte("test"))
 
 			// test show create table
-			readQuery, err = buildQuery(wt.ReadQuery, 1, 4, []string{
+			readQuery, err = buildQuery(types.ReadQuery, 1, 4, []string{
 				"show create table test",
 			})
 			So(err, ShouldBeNil)
@@ -164,7 +162,7 @@ func TestSingleDatabase(t *testing.T) {
 			So(strings.ToUpper(string(byteStr)), ShouldContainSubstring, "CREATE")
 
 			// test show table
-			readQuery, err = buildQuery(wt.ReadQuery, 1, 5, []string{
+			readQuery, err = buildQuery(types.ReadQuery, 1, 5, []string{
 				"show table test",
 			})
 			So(err, ShouldBeNil)
@@ -182,7 +180,7 @@ func TestSingleDatabase(t *testing.T) {
 			So(res.Payload.Rows[1].Values[1], ShouldResemble, []byte("col2"))
 
 			// test desc table
-			readQuery, err = buildQuery(wt.ReadQuery, 1, 6, []string{
+			readQuery, err = buildQuery(types.ReadQuery, 1, 6, []string{
 				"desc test",
 			})
 			So(err, ShouldBeNil)
@@ -200,7 +198,7 @@ func TestSingleDatabase(t *testing.T) {
 			So(res.Payload.Rows[1].Values[1], ShouldResemble, []byte("col2"))
 
 			// test show index from table
-			readQuery, err = buildQuery(wt.ReadQuery, 1, 7, []string{
+			readQuery, err = buildQuery(types.ReadQuery, 1, 7, []string{
 				"show index from table test",
 			})
 			So(err, ShouldBeNil)
@@ -218,9 +216,9 @@ func TestSingleDatabase(t *testing.T) {
 
 		Convey("test read write", func() {
 			// test write query
-			var writeQuery *wt.Request
-			var res *wt.Response
-			writeQuery, err = buildQuery(wt.WriteQuery, 1, 1, []string{
+			var writeQuery *types.Request
+			var res *types.Response
+			writeQuery, err = buildQuery(types.WriteQuery, 1, 1, []string{
 				"create table test (test int)",
 				"insert into test values(1)",
 			})
@@ -233,8 +231,8 @@ func TestSingleDatabase(t *testing.T) {
 			So(res.Header.RowCount, ShouldEqual, 0)
 
 			// test select query
-			var readQuery *wt.Request
-			readQuery, err = buildQuery(wt.ReadQuery, 1, 2, []string{
+			var readQuery *types.Request
+			readQuery, err = buildQuery(types.ReadQuery, 1, 2, []string{
 				"select * from test",
 			})
 			So(err, ShouldBeNil)
@@ -256,9 +254,9 @@ func TestSingleDatabase(t *testing.T) {
 		})
 
 		Convey("test invalid request", func() {
-			var writeQuery *wt.Request
-			var res *wt.Response
-			writeQuery, err = buildQuery(wt.WriteQuery, 1, 1, []string{
+			var writeQuery *types.Request
+			var res *types.Response
+			writeQuery, err = buildQuery(types.WriteQuery, 1, 1, []string{
 				"create table test (test int)",
 				"insert into test values(1)",
 			})
@@ -272,43 +270,43 @@ func TestSingleDatabase(t *testing.T) {
 			So(res.Header.RowCount, ShouldEqual, 0)
 
 			// request again with same sequence
-			writeQuery, err = buildQuery(wt.WriteQuery, 1, 1, []string{
+			writeQuery, err = buildQuery(types.WriteQuery, 1, 1, []string{
 				"insert into test values(2)",
 			})
 			res, err = db.Query(writeQuery)
 			So(err, ShouldNotBeNil)
 
 			// request again with low sequence
-			writeQuery, err = buildQuery(wt.WriteQuery, 1, 0, []string{
+			writeQuery, err = buildQuery(types.WriteQuery, 1, 0, []string{
 				"insert into test values(3)",
 			})
 			res, err = db.Query(writeQuery)
 			So(err, ShouldNotBeNil)
 
 			// request with invalid timestamp
-			writeQuery, err = buildQueryWithTimeShift(wt.WriteQuery, 1, 2, time.Second*100, []string{
+			writeQuery, err = buildQueryWithTimeShift(types.WriteQuery, 1, 2, time.Second*100, []string{
 				"insert into test values(4)",
 			})
 			res, err = db.Query(writeQuery)
 			So(err, ShouldNotBeNil)
 
 			// request with invalid timestamp
-			writeQuery, err = buildQueryWithTimeShift(wt.WriteQuery, 1, 2, -time.Second*100, []string{
+			writeQuery, err = buildQueryWithTimeShift(types.WriteQuery, 1, 2, -time.Second*100, []string{
 				"insert into test values(5)",
 			})
 			res, err = db.Query(writeQuery)
 			So(err, ShouldNotBeNil)
 
 			// request with different connection id
-			writeQuery, err = buildQuery(wt.WriteQuery, 2, 1, []string{
+			writeQuery, err = buildQuery(types.WriteQuery, 2, 1, []string{
 				"insert into test values(6)",
 			})
 			res, err = db.Query(writeQuery)
 			So(err, ShouldBeNil)
 
 			// read query, test records
-			var readQuery *wt.Request
-			readQuery, err = buildQuery(wt.ReadQuery, 1, 2, []string{
+			var readQuery *types.Request
+			readQuery, err = buildQuery(types.ReadQuery, 1, 2, []string{
 				"select * from test",
 			})
 			So(err, ShouldBeNil)
@@ -331,7 +329,7 @@ func TestSingleDatabase(t *testing.T) {
 		})
 
 		Convey("corner case", func() {
-			var req *wt.Request
+			var req *types.Request
 			var err error
 			req, err = buildQuery(-1, 1, 1, []string{
 				"create table test (test int)",
@@ -340,9 +338,9 @@ func TestSingleDatabase(t *testing.T) {
 			_, err = db.Query(req)
 			So(err, ShouldNotBeNil)
 
-			var writeQuery *wt.Request
-			var res *wt.Response
-			writeQuery, err = buildQuery(wt.WriteQuery, 1, 1, []string{
+			var writeQuery *types.Request
+			var res *types.Response
+			writeQuery, err = buildQuery(types.WriteQuery, 1, 1, []string{
 				"create table test (test int)",
 			})
 			So(err, ShouldBeNil)
@@ -350,8 +348,8 @@ func TestSingleDatabase(t *testing.T) {
 			So(err, ShouldBeNil)
 
 			// read query, test records
-			var readQuery *wt.Request
-			readQuery, err = buildQuery(wt.ReadQuery, 1, 2, []string{
+			var readQuery *types.Request
+			readQuery, err = buildQuery(types.ReadQuery, 1, 2, []string{
 				"select * from test",
 			})
 			So(err, ShouldBeNil)
@@ -366,7 +364,7 @@ func TestSingleDatabase(t *testing.T) {
 			So(res.Payload.Rows, ShouldBeEmpty)
 
 			// write query, test failed
-			writeQuery, err = buildQuery(wt.WriteQuery, 1, 3, []string{
+			writeQuery, err = buildQuery(types.WriteQuery, 1, 3, []string{
 				"insert into test2 values(1)", // table should not exists
 			})
 			So(err, ShouldBeNil)
@@ -374,7 +372,7 @@ func TestSingleDatabase(t *testing.T) {
 			So(err, ShouldNotBeNil)
 
 			// read query, test dynamic fields
-			readQuery, err = buildQuery(wt.ReadQuery, 1, 4, []string{
+			readQuery, err = buildQuery(types.ReadQuery, 1, 4, []string{
 				"select 1 as test",
 			})
 			So(err, ShouldBeNil)
@@ -389,7 +387,7 @@ func TestSingleDatabase(t *testing.T) {
 			So(res.Payload.Rows, ShouldNotBeEmpty)
 
 			// test ack
-			var ack *wt.Ack
+			var ack *types.Ack
 			ack, err = buildAck(res)
 			So(err, ShouldBeNil)
 
@@ -449,7 +447,7 @@ func TestInitFailed(t *testing.T) {
 		}
 
 		// create genesis block
-		var block *ct.Block
+		var block *types.Block
 		block, err = createRandomBlock(rootHash, true)
 		So(err, ShouldBeNil)
 
@@ -502,7 +500,7 @@ func TestDatabaseRecycle(t *testing.T) {
 		}
 
 		// create genesis block
-		var block *ct.Block
+		var block *types.Block
 		block, err = createRandomBlock(rootHash, true)
 		So(err, ShouldBeNil)
 
@@ -512,9 +510,9 @@ func TestDatabaseRecycle(t *testing.T) {
 		So(err, ShouldBeNil)
 
 		// do some query
-		var writeQuery *wt.Request
-		var res *wt.Response
-		writeQuery, err = buildQuery(wt.WriteQuery, 1, 1, []string{
+		var writeQuery *types.Request
+		var res *types.Response
+		writeQuery, err = buildQuery(types.WriteQuery, 1, 1, []string{
 			"create table test (test int)",
 			"insert into test values(1)",
 		})
@@ -527,8 +525,8 @@ func TestDatabaseRecycle(t *testing.T) {
 		So(res.Header.RowCount, ShouldEqual, 0)
 
 		// test select query
-		var readQuery *wt.Request
-		readQuery, err = buildQuery(wt.ReadQuery, 1, 2, []string{
+		var readQuery *types.Request
+		readQuery, err = buildQuery(types.ReadQuery, 1, 2, []string{
 			"select * from test",
 		})
 		So(err, ShouldBeNil)
@@ -553,7 +551,7 @@ func TestDatabaseRecycle(t *testing.T) {
 	})
 }
 
-func buildAck(res *wt.Response) (ack *wt.Ack, err error) {
+func buildAck(res *types.Response) (ack *types.Ack, err error) {
 	// get node id
 	var nodeID proto.NodeID
 	if nodeID, err = kms.GetLocalNodeID(); err != nil {
@@ -567,9 +565,9 @@ func buildAck(res *wt.Response) (ack *wt.Ack, err error) {
 		return
 	}
 
-	ack = &wt.Ack{
-		Header: wt.SignedAckHeader{
-			AckHeader: wt.AckHeader{
+	ack = &types.Ack{
+		Header: types.SignedAckHeader{
+			AckHeader: types.AckHeader{
 				Response:  res.Header,
 				NodeID:    nodeID,
 				Timestamp: getLocalTime(),
@@ -582,19 +580,19 @@ func buildAck(res *wt.Response) (ack *wt.Ack, err error) {
 	return
 }
 
-func buildQuery(queryType wt.QueryType, connID uint64, seqNo uint64, queries []string) (query *wt.Request, err error) {
+func buildQuery(queryType types.QueryType, connID uint64, seqNo uint64, queries []string) (query *types.Request, err error) {
 	return buildQueryEx(queryType, connID, seqNo, time.Duration(0), proto.DatabaseID(""), queries)
 }
 
-func buildQueryWithDatabaseID(queryType wt.QueryType, connID uint64, seqNo uint64, databaseID proto.DatabaseID, queries []string) (query *wt.Request, err error) {
+func buildQueryWithDatabaseID(queryType types.QueryType, connID uint64, seqNo uint64, databaseID proto.DatabaseID, queries []string) (query *types.Request, err error) {
 	return buildQueryEx(queryType, connID, seqNo, time.Duration(0), databaseID, queries)
 }
 
-func buildQueryWithTimeShift(queryType wt.QueryType, connID uint64, seqNo uint64, timeShift time.Duration, queries []string) (query *wt.Request, err error) {
+func buildQueryWithTimeShift(queryType types.QueryType, connID uint64, seqNo uint64, timeShift time.Duration, queries []string) (query *types.Request, err error) {
 	return buildQueryEx(queryType, connID, seqNo, timeShift, proto.DatabaseID(""), queries)
 }
 
-func buildQueryEx(queryType wt.QueryType, connID uint64, seqNo uint64, timeShift time.Duration, databaseID proto.DatabaseID, queries []string) (query *wt.Request, err error) {
+func buildQueryEx(queryType types.QueryType, connID uint64, seqNo uint64, timeShift time.Duration, databaseID proto.DatabaseID, queries []string) (query *types.Request, err error) {
 	// get node id
 	var nodeID proto.NodeID
 	if nodeID, err = kms.GetLocalNodeID(); err != nil {
@@ -612,15 +610,15 @@ func buildQueryEx(queryType wt.QueryType, connID uint64, seqNo uint64, timeShift
 	tm = tm.Add(-timeShift)
 
 	// build queries
-	realQueries := make([]wt.Query, len(queries))
+	realQueries := make([]types.Query, len(queries))
 
 	for i, v := range queries {
 		realQueries[i].Pattern = v
 	}
 
-	query = &wt.Request{
-		Header: wt.SignedRequestHeader{
-			RequestHeader: wt.RequestHeader{
+	query = &types.Request{
+		Header: types.SignedRequestHeader{
+			RequestHeader: types.RequestHeader{
 				DatabaseID:   databaseID,
 				QueryType:    queryType,
 				NodeID:       nodeID,
@@ -629,7 +627,7 @@ func buildQueryEx(queryType wt.QueryType, connID uint64, seqNo uint64, timeShift
 				Timestamp:    tm,
 			},
 		},
-		Payload: wt.RequestPayload{
+		Payload: types.RequestPayload{
 			Queries: realQueries,
 		},
 	}
@@ -742,7 +740,7 @@ func initNode() (cleanupFunc func(), server *rpc.Server, err error) {
 }
 
 // copied from sqlchain.xxx_test.
-func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error) {
+func createRandomBlock(parent hash.Hash, isGenesis bool) (b *types.Block, err error) {
 	// Generate key pair
 	priv, pub, err := asymmetric.GenSecp256k1KeyPair()
 
@@ -753,9 +751,9 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 	h := hash.Hash{}
 	rand.Read(h[:])
 
-	b = &ct.Block{
-		SignedHeader: ct.SignedHeader{
-			Header: ct.Header{
+	b = &types.Block{
+		SignedHeader: types.SignedHeader{
+			Header: types.Header{
 				Version:     0x01000000,
 				Producer:    proto.NodeID(h.String()),
 				GenesisHash: rootHash,
@@ -763,12 +761,6 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 				Timestamp:   time.Now().UTC(),
 			},
 		},
-		Queries: make([]*hash.Hash, rand.Intn(10)+10),
-	}
-
-	for i := range b.Queries {
-		b.Queries[i] = new(hash.Hash)
-		rand.Read(b.Queries[i][:])
 	}
 
 	if isGenesis {
@@ -801,7 +793,7 @@ func createRandomBlock(parent hash.Hash, isGenesis bool) (b *ct.Block, err error
 // fake BPDB service
 type stubBPDBService struct{}
 
-func (s *stubBPDBService) CreateDatabase(req *bp.CreateDatabaseRequest, resp *bp.CreateDatabaseResponse) (err error) {
+func (s *stubBPDBService) CreateDatabase(req *types.CreateDatabaseRequest, resp *types.CreateDatabaseResponse) (err error) {
 	if resp.Header.InstanceMeta, err = s.getInstanceMeta("db2"); err != nil {
 		return
 	}
@@ -816,11 +808,11 @@ func (s *stubBPDBService) CreateDatabase(req *bp.CreateDatabaseRequest, resp *bp
 	return
 }
 
-func (s *stubBPDBService) DropDatabase(req *bp.DropDatabaseRequest, resp *bp.DropDatabaseRequest) (err error) {
+func (s *stubBPDBService) DropDatabase(req *types.DropDatabaseRequest, resp *types.DropDatabaseRequest) (err error) {
 	return
 }
 
-func (s *stubBPDBService) GetDatabase(req *bp.GetDatabaseRequest, resp *bp.GetDatabaseResponse) (err error) {
+func (s *stubBPDBService) GetDatabase(req *types.GetDatabaseRequest, resp *types.GetDatabaseResponse) (err error) {
 	if resp.Header.InstanceMeta, err = s.getInstanceMeta(req.Header.DatabaseID); err != nil {
 		return
 	}
@@ -835,8 +827,8 @@ func (s *stubBPDBService) GetDatabase(req *bp.GetDatabaseRequest, resp *bp.GetDa
 	return
 }
 
-func (s *stubBPDBService) GetNodeDatabases(req *wt.InitService, resp *wt.InitServiceResponse) (err error) {
-	resp.Header.Instances = make([]wt.ServiceInstance, 1)
+func (s *stubBPDBService) GetNodeDatabases(req *types.InitService, resp *types.InitServiceResponse) (err error) {
+	resp.Header.Instances = make([]types.ServiceInstance, 1)
 	resp.Header.Instances[0], err = s.getInstanceMeta("db2")
 	if resp.Header.Signee, err = kms.GetLocalPublicKey(); err != nil {
 		return
@@ -851,7 +843,7 @@ func (s *stubBPDBService) GetNodeDatabases(req *wt.InitService, resp *wt.InitSer
 	return
 }
 
-func (s *stubBPDBService) getInstanceMeta(dbID proto.DatabaseID) (instance wt.ServiceInstance, err error) {
+func (s *stubBPDBService) getInstanceMeta(dbID proto.DatabaseID) (instance types.ServiceInstance, err error) {
 	var privKey *asymmetric.PrivateKey
 	if privKey, err = kms.GetLocalPrivateKey(); err != nil {
 		return
diff --git a/worker/dbms.go b/worker/dbms.go
index 769c6d45e..647d4d786 100644
--- a/worker/dbms.go
+++ b/worker/dbms.go
@@ -23,14 +23,13 @@ import (
 	"path/filepath"
 	"sync"
 
-	kt "github.com/CovenantSQL/CovenantSQL/kayak/types"
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
 	"github.com/CovenantSQL/CovenantSQL/sqlchain"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/CovenantSQL/CovenantSQL/utils"
 	"github.com/CovenantSQL/CovenantSQL/utils/log"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
 	"github.com/pkg/errors"
 )
 
@@ -132,7 +131,7 @@ func (dbms *DBMS) Init() (err error) {
 	}
 
 	// load current peers info from block producer
-	var dbMapping []wt.ServiceInstance
+	var dbMapping []types.ServiceInstance
 	if dbMapping, err = dbms.getMappedInstances(); err != nil {
 		err = errors.Wrap(err, "get mapped instances failed")
 		return
@@ -147,7 +146,7 @@ func (dbms *DBMS) Init() (err error) {
 	return
 }
 
-func (dbms *DBMS) initDatabases(meta *DBMSMeta, conf []wt.ServiceInstance) (err error) {
+func (dbms *DBMS) initDatabases(meta *DBMSMeta, conf []types.ServiceInstance) (err error) {
 	currentInstance := make(map[proto.DatabaseID]bool)
 
 	for _, instanceConf := range conf {
@@ -177,7 +176,7 @@ func (dbms *DBMS) initDatabases(meta *DBMSMeta, conf []wt.ServiceInstance) (err
 }
 
 // Create add new database to the miner dbms.
-func (dbms *DBMS) Create(instance *wt.ServiceInstance, cleanup bool) (err error) {
+func (dbms *DBMS) Create(instance *types.ServiceInstance, cleanup bool) (err error) {
 	if _, alreadyExists := dbms.getMeta(instance.DatabaseID); alreadyExists {
 		return ErrAlreadyExists
 	}
@@ -245,7 +244,7 @@ func (dbms *DBMS) Drop(dbID proto.DatabaseID) (err error) {
 }
 
 // Update apply the new peers config to dbms.
-func (dbms *DBMS) Update(instance *wt.ServiceInstance) (err error) {
+func (dbms *DBMS) Update(instance *types.ServiceInstance) (err error) {
 	var db *Database
 	var exists bool
 
@@ -258,7 +257,7 @@ func (dbms *DBMS) Update(instance *wt.ServiceInstance) (err error) {
 }
 
 // Query handles query request in dbms.
-func (dbms *DBMS) Query(req *wt.Request) (res *wt.Response, err error) {
+func (dbms *DBMS) Query(req *types.Request) (res *types.Response, err error) {
 	var db *Database
 	var exists bool
 
@@ -273,7 +272,7 @@ func (dbms *DBMS) Query(req *wt.Request) (res *wt.Response, err error) {
 }
 
 // Ack handles ack of previous response.
-func (dbms *DBMS) Ack(ack *wt.Ack) (err error) {
+func (dbms *DBMS) Ack(ack *types.Ack) (err error) {
 	var db *Database
 	var exists bool
 
@@ -287,32 +286,6 @@ func (dbms *DBMS) Ack(ack *wt.Ack) (err error) {
 	return db.Ack(ack)
 }
 
-// GetRequest handles fetching original request of previous transactions.
-func (dbms *DBMS) GetRequest(dbID proto.DatabaseID, offset uint64) (query *wt.Request, err error) {
-	var db *Database
-	var exists bool
-
-	if db, exists = dbms.getMeta(dbID); !exists {
-		err = ErrNotExists
-		return
-	}
-
-	var req interface{}
-	if req, err = db.getLog(offset); err != nil {
-		err = errors.Wrap(err, "get log failed")
-		return
-	}
-
-	// decode requests
-	var ok bool
-	if query, ok = req.(*wt.Request); !ok {
-		err = errors.Wrap(kt.ErrInvalidLog, "convert log to request failed")
-		return
-	}
-
-	return
-}
-
 func (dbms *DBMS) getMeta(dbID proto.DatabaseID) (db *Database, exists bool) {
 	var rawDB interface{}
 
@@ -338,14 +311,14 @@ func (dbms *DBMS) removeMeta(dbID proto.DatabaseID) (err error) {
 	return dbms.writeMeta()
 }
 
-func (dbms *DBMS) getMappedInstances() (instances []wt.ServiceInstance, err error) {
+func (dbms *DBMS) getMappedInstances() (instances []types.ServiceInstance, err error) {
 	var bpNodeID proto.NodeID
 	if bpNodeID, err = rpc.GetCurrentBP(); err != nil {
 		return
 	}
 
-	req := &wt.InitService{}
-	res := new(wt.InitServiceResponse)
+	req := &types.InitService{}
+	res := new(types.InitServiceResponse)
 
 	if err = rpc.NewCaller().CallNode(bpNodeID, route.BPDBGetNodeDatabases.String(), req, res); err != nil {
 		return
diff --git a/worker/dbms_config.go b/worker/dbms_config.go
index d4f671659..bc8fcded7 100644
--- a/worker/dbms_config.go
+++ b/worker/dbms_config.go
@@ -24,7 +24,7 @@ import (
 
 var (
 	// DefaultMaxReqTimeGap defines max time gap between request and server.
-	DefaultMaxReqTimeGap = time.Second * 5
+	DefaultMaxReqTimeGap = time.Minute
 )
 
 // DBMSConfig defines the local multi-database management system config.
diff --git a/worker/dbms_rpc.go b/worker/dbms_rpc.go
index 1daffa148..0bd8a5deb 100644
--- a/worker/dbms_rpc.go
+++ b/worker/dbms_rpc.go
@@ -17,12 +17,12 @@
 package worker
 
 import (
-	"context"
-	"runtime/trace"
+	//"context"
+	//"runtime/trace"
 
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	"github.com/pkg/errors"
 	"github.com/rcrowley/go-metrics"
 )
@@ -53,16 +53,16 @@ func NewDBMSRPCService(serviceName string, server *rpc.Server, dbms *DBMS) (serv
 }
 
 // Query rpc, called by client to issue read/write query.
-func (rpc *DBMSRPCService) Query(req *wt.Request, res *wt.Response) (err error) {
+func (rpc *DBMSRPCService) Query(req *types.Request, res *types.Response) (err error) {
 	// Just need to verify signature in db.saveAck
 	//if err = req.Verify(); err != nil {
 	//	dbQueryFailCounter.Mark(1)
 	//	return
 	//}
-	ctx := context.Background()
-	ctx, task := trace.NewTask(ctx, "Query")
-	defer task.End()
-	defer trace.StartRegion(ctx, "QueryRegion").End()
+	//ctx := context.Background()
+	//ctx, task := trace.NewTask(ctx, "Query")
+	//defer task.End()
+	//defer trace.StartRegion(ctx, "QueryRegion").End()
 	// verify query is sent from the request node
 	if req.Envelope.NodeID.String() != string(req.Header.NodeID) {
 		// node id mismatch
@@ -71,7 +71,7 @@ func (rpc *DBMSRPCService) Query(req *wt.Request, res *wt.Response) (err error)
 		return
 	}
 
-	var r *wt.Response
+	var r *types.Response
 	if r, err = rpc.dbms.Query(req); err != nil {
 		dbQueryFailCounter.Mark(1)
 		return
@@ -84,15 +84,15 @@ func (rpc *DBMSRPCService) Query(req *wt.Request, res *wt.Response) (err error)
 }
 
 // Ack rpc, called by client to confirm read request.
-func (rpc *DBMSRPCService) Ack(ack *wt.Ack, _ *wt.AckResponse) (err error) {
+func (rpc *DBMSRPCService) Ack(ack *types.Ack, _ *types.AckResponse) (err error) {
 	// Just need to verify signature in db.saveAck
 	//if err = ack.Verify(); err != nil {
 	//	return
 	//}
-	ctx := context.Background()
-	ctx, task := trace.NewTask(ctx, "Ack")
-	defer task.End()
-	defer trace.StartRegion(ctx, "AckRegion").End()
+	//ctx := context.Background()
+	//ctx, task := trace.NewTask(ctx, "Ack")
+	//defer task.End()
+	//defer trace.StartRegion(ctx, "AckRegion").End()
 
 	// verify if ack node is the original ack node
 	if ack.Envelope.NodeID.String() != string(ack.Header.Response.Request.NodeID) {
@@ -107,7 +107,7 @@ func (rpc *DBMSRPCService) Ack(ack *wt.Ack, _ *wt.AckResponse) (err error) {
 }
 
 // Deploy rpc, called by BP to create/drop database and update peers.
-func (rpc *DBMSRPCService) Deploy(req *wt.UpdateService, _ *wt.UpdateServiceResponse) (err error) {
+func (rpc *DBMSRPCService) Deploy(req *types.UpdateService, _ *types.UpdateServiceResponse) (err error) {
 	// verify request node is block producer
 	if !route.IsPermitted(&req.Envelope, route.DBSDeploy) {
 		err = errors.Wrap(ErrInvalidRequest, "node not permitted for deploy request")
@@ -121,20 +121,13 @@ func (rpc *DBMSRPCService) Deploy(req *wt.UpdateService, _ *wt.UpdateServiceResp
 
 	// create/drop/update
 	switch req.Header.Op {
-	case wt.CreateDB:
+	case types.CreateDB:
 		err = rpc.dbms.Create(&req.Header.Instance, true)
-	case wt.UpdateDB:
+	case types.UpdateDB:
 		err = rpc.dbms.Update(&req.Header.Instance)
-	case wt.DropDB:
+	case types.DropDB:
 		err = rpc.dbms.Drop(req.Header.Instance.DatabaseID)
 	}
 
 	return
 }
-
-// GetRequest rpc, called by observer to fetch original request by log offset.
-func (rpc *DBMSRPCService) GetRequest(req *wt.GetRequestReq, resp *wt.GetRequestResp) (err error) {
-	// TODO(xq262144), check permission
-	resp.Request, err = rpc.dbms.GetRequest(req.DatabaseID, req.LogOffset)
-	return
-}
diff --git a/worker/dbms_test.go b/worker/dbms_test.go
index 7b8d43fd6..a424828cf 100644
--- a/worker/dbms_test.go
+++ b/worker/dbms_test.go
@@ -27,8 +27,7 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/proto"
 	"github.com/CovenantSQL/CovenantSQL/route"
 	"github.com/CovenantSQL/CovenantSQL/rpc"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
-	wt "github.com/CovenantSQL/CovenantSQL/worker/types"
+	"github.com/CovenantSQL/CovenantSQL/types"
 	. "github.com/smartystreets/goconvey/convey"
 )
 
@@ -63,10 +62,10 @@ func TestDBMS(t *testing.T) {
 		So(err, ShouldBeNil)
 
 		// add database
-		var req *wt.UpdateService
-		var res wt.UpdateServiceResponse
+		var req *types.UpdateService
+		var res types.UpdateServiceResponse
 		var peers *proto.Peers
-		var block *ct.Block
+		var block *types.Block
 
 		dbID := proto.DatabaseID("db")
 
@@ -79,9 +78,9 @@ func TestDBMS(t *testing.T) {
 		So(err, ShouldBeNil)
 
 		// call with no BP privilege
-		req = new(wt.UpdateService)
-		req.Header.Op = wt.CreateDB
-		req.Header.Instance = wt.ServiceInstance{
+		req = new(types.UpdateService)
+		req.Header.Op = types.CreateDB
+		req.Header.Instance = types.ServiceInstance{
 			DatabaseID:   dbID,
 			Peers:        peers,
 			GenesisBlock: block,
@@ -96,9 +95,9 @@ func TestDBMS(t *testing.T) {
 
 			Convey("queries", func() {
 				// sending write query
-				var writeQuery *wt.Request
-				var queryRes *wt.Response
-				writeQuery, err = buildQueryWithDatabaseID(wt.WriteQuery, 1, 1, dbID, []string{
+				var writeQuery *types.Request
+				var queryRes *types.Response
+				writeQuery, err = buildQueryWithDatabaseID(types.WriteQuery, 1, 1, dbID, []string{
 					"create table test (test int)",
 					"insert into test values(1)",
 				})
@@ -109,20 +108,10 @@ func TestDBMS(t *testing.T) {
 				err = queryRes.Verify()
 				So(err, ShouldBeNil)
 				So(queryRes.Header.RowCount, ShouldEqual, 0)
-				So(queryRes.Header.LogOffset, ShouldEqual, 0)
-
-				var reqGetRequest wt.GetRequestReq
-				var respGetRequest *wt.GetRequestResp
-
-				reqGetRequest.DatabaseID = dbID
-				reqGetRequest.LogOffset = queryRes.Header.LogOffset
-				err = testRequest(route.DBSGetRequest, reqGetRequest, &respGetRequest)
-				So(err, ShouldBeNil)
-				So(respGetRequest.Request.Header.Hash, ShouldResemble, writeQuery.Header.Hash)
 
 				// sending read query
-				var readQuery *wt.Request
-				readQuery, err = buildQueryWithDatabaseID(wt.ReadQuery, 1, 2, dbID, []string{
+				var readQuery *types.Request
+				readQuery, err = buildQueryWithDatabaseID(types.ReadQuery, 1, 2, dbID, []string{
 					"select * from test",
 				})
 				So(err, ShouldBeNil)
@@ -139,20 +128,20 @@ func TestDBMS(t *testing.T) {
 				So(queryRes.Payload.Rows[0].Values[0], ShouldEqual, 1)
 
 				// sending read ack
-				var ack *wt.Ack
+				var ack *types.Ack
 				ack, err = buildAck(queryRes)
 				So(err, ShouldBeNil)
 
-				var ackRes wt.AckResponse
+				var ackRes types.AckResponse
 				err = testRequest(route.DBSAck, ack, &ackRes)
 				So(err, ShouldBeNil)
 			})
 
 			Convey("query non-existent database", func() {
 				// sending write query
-				var writeQuery *wt.Request
-				var queryRes *wt.Response
-				writeQuery, err = buildQueryWithDatabaseID(wt.WriteQuery, 1, 1,
+				var writeQuery *types.Request
+				var queryRes *types.Response
+				writeQuery, err = buildQueryWithDatabaseID(types.WriteQuery, 1, 1,
 					proto.DatabaseID("db_not_exists"), []string{
 						"create table test (test int)",
 						"insert into test values(1)",
@@ -168,9 +157,9 @@ func TestDBMS(t *testing.T) {
 				peers, err = getPeers(2)
 				So(err, ShouldBeNil)
 
-				req = new(wt.UpdateService)
-				req.Header.Op = wt.UpdateDB
-				req.Header.Instance = wt.ServiceInstance{
+				req = new(types.UpdateService)
+				req.Header.Op = types.UpdateDB
+				req.Header.Instance = types.ServiceInstance{
 					DatabaseID: dbID,
 					Peers:      peers,
 				}
@@ -183,9 +172,9 @@ func TestDBMS(t *testing.T) {
 
 			Convey("drop database before shutdown", func() {
 				// drop database
-				req = new(wt.UpdateService)
-				req.Header.Op = wt.DropDB
-				req.Header.Instance = wt.ServiceInstance{
+				req = new(types.UpdateService)
+				req.Header.Op = types.DropDB
+				req.Header.Instance = types.ServiceInstance{
 					DatabaseID: dbID,
 				}
 				err = req.Sign(privateKey)
diff --git a/worker/types/ack_type.go b/worker/otypes/ack_type.go
similarity index 99%
rename from worker/types/ack_type.go
rename to worker/otypes/ack_type.go
index f386e7556..795c99e1a 100644
--- a/worker/types/ack_type.go
+++ b/worker/otypes/ack_type.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"time"
diff --git a/worker/types/ack_type_gen.go b/worker/otypes/ack_type_gen.go
similarity index 99%
rename from worker/types/ack_type_gen.go
rename to worker/otypes/ack_type_gen.go
index 47511dcee..9c4a845c0 100644
--- a/worker/types/ack_type_gen.go
+++ b/worker/otypes/ack_type_gen.go
@@ -1,4 +1,4 @@
-package types
+package otypes
 
 // Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
 
diff --git a/worker/otypes/ack_type_gen_test.go b/worker/otypes/ack_type_gen_test.go
new file mode 100644
index 000000000..3fc0faf87
--- /dev/null
+++ b/worker/otypes/ack_type_gen_test.go
@@ -0,0 +1,158 @@
+package otypes
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/binary"
+	"testing"
+)
+
+func TestMarshalHashAck(t *testing.T) {
+	v := Ack{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashAck(b *testing.B) {
+	v := Ack{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgAck(b *testing.B) {
+	v := Ack{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashAckHeader(t *testing.T) {
+	v := AckHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashAckHeader(b *testing.B) {
+	v := AckHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgAckHeader(b *testing.B) {
+	v := AckHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashAckResponse(t *testing.T) {
+	v := AckResponse{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashAckResponse(b *testing.B) {
+	v := AckResponse{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgAckResponse(b *testing.B) {
+	v := AckResponse{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashSignedAckHeader(t *testing.T) {
+	v := SignedAckHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashSignedAckHeader(b *testing.B) {
+	v := SignedAckHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgSignedAckHeader(b *testing.B) {
+	v := SignedAckHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
diff --git a/chain/doc.go b/worker/otypes/doc.go
similarity index 89%
rename from chain/doc.go
rename to worker/otypes/doc.go
index 2fa161437..089862dc6 100644
--- a/chain/doc.go
+++ b/worker/otypes/doc.go
@@ -14,5 +14,7 @@
  * limitations under the License.
  */
 
-// Package chain defines commonly types for block chain.
-package chain
+/*
+Package otypes defines miner node export types.
+*/
+package otypes
diff --git a/worker/types/errors.go b/worker/otypes/errors.go
similarity index 98%
rename from worker/types/errors.go
rename to worker/otypes/errors.go
index b95037572..5c44a3c9d 100644
--- a/worker/types/errors.go
+++ b/worker/otypes/errors.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import "errors"
 
diff --git a/worker/types/get_request.go b/worker/otypes/get_request.go
similarity index 98%
rename from worker/types/get_request.go
rename to worker/otypes/get_request.go
index 5f19cef99..cd1bd4567 100644
--- a/worker/types/get_request.go
+++ b/worker/otypes/get_request.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import "github.com/CovenantSQL/CovenantSQL/proto"
 
diff --git a/worker/types/init_service_type.go b/worker/otypes/init_service_type.go
similarity index 97%
rename from worker/types/init_service_type.go
rename to worker/otypes/init_service_type.go
index 6007729db..54d2af65a 100644
--- a/worker/types/init_service_type.go
+++ b/worker/otypes/init_service_type.go
@@ -14,13 +14,13 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
 	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
 	"github.com/CovenantSQL/CovenantSQL/proto"
-	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/types"
+	ct "github.com/CovenantSQL/CovenantSQL/sqlchain/otypes"
 )
 
 //go:generate hsp
diff --git a/worker/types/init_service_type_gen.go b/worker/otypes/init_service_type_gen.go
similarity index 99%
rename from worker/types/init_service_type_gen.go
rename to worker/otypes/init_service_type_gen.go
index 1fcce43a4..a538613bb 100644
--- a/worker/types/init_service_type_gen.go
+++ b/worker/otypes/init_service_type_gen.go
@@ -1,4 +1,4 @@
-package types
+package otypes
 
 // Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
 
diff --git a/worker/otypes/init_service_type_gen_test.go b/worker/otypes/init_service_type_gen_test.go
new file mode 100644
index 000000000..ee88b0eb6
--- /dev/null
+++ b/worker/otypes/init_service_type_gen_test.go
@@ -0,0 +1,232 @@
+package otypes
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/binary"
+	"testing"
+)
+
+func TestMarshalHashInitService(t *testing.T) {
+	v := InitService{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashInitService(b *testing.B) {
+	v := InitService{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgInitService(b *testing.B) {
+	v := InitService{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashInitServiceResponse(t *testing.T) {
+	v := InitServiceResponse{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashInitServiceResponse(b *testing.B) {
+	v := InitServiceResponse{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgInitServiceResponse(b *testing.B) {
+	v := InitServiceResponse{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashInitServiceResponseHeader(t *testing.T) {
+	v := InitServiceResponseHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashInitServiceResponseHeader(b *testing.B) {
+	v := InitServiceResponseHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgInitServiceResponseHeader(b *testing.B) {
+	v := InitServiceResponseHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashResourceMeta(t *testing.T) {
+	v := ResourceMeta{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashResourceMeta(b *testing.B) {
+	v := ResourceMeta{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgResourceMeta(b *testing.B) {
+	v := ResourceMeta{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashServiceInstance(t *testing.T) {
+	v := ServiceInstance{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashServiceInstance(b *testing.B) {
+	v := ServiceInstance{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgServiceInstance(b *testing.B) {
+	v := ServiceInstance{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashSignedInitServiceResponseHeader(t *testing.T) {
+	v := SignedInitServiceResponseHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashSignedInitServiceResponseHeader(b *testing.B) {
+	v := SignedInitServiceResponseHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgSignedInitServiceResponseHeader(b *testing.B) {
+	v := SignedInitServiceResponseHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
diff --git a/worker/types/no_ack_report_type.go b/worker/otypes/no_ack_report_type.go
similarity index 99%
rename from worker/types/no_ack_report_type.go
rename to worker/otypes/no_ack_report_type.go
index bda6aee91..24b0fbfc4 100644
--- a/worker/types/no_ack_report_type.go
+++ b/worker/otypes/no_ack_report_type.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"time"
diff --git a/worker/types/no_ack_report_type_gen.go b/worker/otypes/no_ack_report_type_gen.go
similarity index 99%
rename from worker/types/no_ack_report_type_gen.go
rename to worker/otypes/no_ack_report_type_gen.go
index 8b1e57cd9..d2a3408b7 100644
--- a/worker/types/no_ack_report_type_gen.go
+++ b/worker/otypes/no_ack_report_type_gen.go
@@ -1,4 +1,4 @@
-package types
+package otypes
 
 // Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
 
diff --git a/worker/otypes/no_ack_report_type_gen_test.go b/worker/otypes/no_ack_report_type_gen_test.go
new file mode 100644
index 000000000..bf3e1bb8b
--- /dev/null
+++ b/worker/otypes/no_ack_report_type_gen_test.go
@@ -0,0 +1,232 @@
+package otypes
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/binary"
+	"testing"
+)
+
+func TestMarshalHashAggrNoAckReport(t *testing.T) {
+	v := AggrNoAckReport{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashAggrNoAckReport(b *testing.B) {
+	v := AggrNoAckReport{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgAggrNoAckReport(b *testing.B) {
+	v := AggrNoAckReport{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashAggrNoAckReportHeader(t *testing.T) {
+	v := AggrNoAckReportHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashAggrNoAckReportHeader(b *testing.B) {
+	v := AggrNoAckReportHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgAggrNoAckReportHeader(b *testing.B) {
+	v := AggrNoAckReportHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashNoAckReport(t *testing.T) {
+	v := NoAckReport{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashNoAckReport(b *testing.B) {
+	v := NoAckReport{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgNoAckReport(b *testing.B) {
+	v := NoAckReport{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashNoAckReportHeader(t *testing.T) {
+	v := NoAckReportHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashNoAckReportHeader(b *testing.B) {
+	v := NoAckReportHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgNoAckReportHeader(b *testing.B) {
+	v := NoAckReportHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashSignedAggrNoAckReportHeader(t *testing.T) {
+	v := SignedAggrNoAckReportHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashSignedAggrNoAckReportHeader(b *testing.B) {
+	v := SignedAggrNoAckReportHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgSignedAggrNoAckReportHeader(b *testing.B) {
+	v := SignedAggrNoAckReportHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashSignedNoAckReportHeader(t *testing.T) {
+	v := SignedNoAckReportHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashSignedNoAckReportHeader(b *testing.B) {
+	v := SignedNoAckReportHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgSignedNoAckReportHeader(b *testing.B) {
+	v := SignedNoAckReportHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
diff --git a/worker/types/request_type.go b/worker/otypes/request_type.go
similarity index 99%
rename from worker/types/request_type.go
rename to worker/otypes/request_type.go
index 01d94cb85..768c3165a 100644
--- a/worker/types/request_type.go
+++ b/worker/otypes/request_type.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"time"
diff --git a/worker/types/request_type_gen.go b/worker/otypes/request_type_gen.go
similarity index 99%
rename from worker/types/request_type_gen.go
rename to worker/otypes/request_type_gen.go
index c20cd58ba..0dd0e6375 100644
--- a/worker/types/request_type_gen.go
+++ b/worker/otypes/request_type_gen.go
@@ -1,4 +1,4 @@
-package types
+package otypes
 
 // Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
 
diff --git a/worker/otypes/request_type_gen_test.go b/worker/otypes/request_type_gen_test.go
new file mode 100644
index 000000000..c1371bf13
--- /dev/null
+++ b/worker/otypes/request_type_gen_test.go
@@ -0,0 +1,269 @@
+package otypes
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/binary"
+	"testing"
+)
+
+func TestMarshalHashNamedArg(t *testing.T) {
+	v := NamedArg{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashNamedArg(b *testing.B) {
+	v := NamedArg{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgNamedArg(b *testing.B) {
+	v := NamedArg{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashQuery(t *testing.T) {
+	v := Query{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashQuery(b *testing.B) {
+	v := Query{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgQuery(b *testing.B) {
+	v := Query{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashQueryKey(t *testing.T) {
+	v := QueryKey{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashQueryKey(b *testing.B) {
+	v := QueryKey{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgQueryKey(b *testing.B) {
+	v := QueryKey{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashRequest(t *testing.T) {
+	v := Request{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashRequest(b *testing.B) {
+	v := Request{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgRequest(b *testing.B) {
+	v := Request{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashRequestHeader(t *testing.T) {
+	v := RequestHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashRequestHeader(b *testing.B) {
+	v := RequestHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgRequestHeader(b *testing.B) {
+	v := RequestHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashRequestPayload(t *testing.T) {
+	v := RequestPayload{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashRequestPayload(b *testing.B) {
+	v := RequestPayload{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgRequestPayload(b *testing.B) {
+	v := RequestPayload{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashSignedRequestHeader(t *testing.T) {
+	v := SignedRequestHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashSignedRequestHeader(b *testing.B) {
+	v := SignedRequestHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgSignedRequestHeader(b *testing.B) {
+	v := SignedRequestHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
diff --git a/worker/types/response_type.go b/worker/otypes/response_type.go
similarity index 99%
rename from worker/types/response_type.go
rename to worker/otypes/response_type.go
index de55945af..931eaa06d 100644
--- a/worker/types/response_type.go
+++ b/worker/otypes/response_type.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"time"
diff --git a/worker/types/response_type_gen.go b/worker/otypes/response_type_gen.go
similarity index 99%
rename from worker/types/response_type_gen.go
rename to worker/otypes/response_type_gen.go
index 898cbfa6e..b3d6e68ce 100644
--- a/worker/types/response_type_gen.go
+++ b/worker/otypes/response_type_gen.go
@@ -1,4 +1,4 @@
-package types
+package otypes
 
 // Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
 
diff --git a/worker/otypes/response_type_gen_test.go b/worker/otypes/response_type_gen_test.go
new file mode 100644
index 000000000..3b263b1ed
--- /dev/null
+++ b/worker/otypes/response_type_gen_test.go
@@ -0,0 +1,195 @@
+package otypes
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/binary"
+	"testing"
+)
+
+func TestMarshalHashResponse(t *testing.T) {
+	v := Response{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashResponse(b *testing.B) {
+	v := Response{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgResponse(b *testing.B) {
+	v := Response{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashResponseHeader(t *testing.T) {
+	v := ResponseHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashResponseHeader(b *testing.B) {
+	v := ResponseHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgResponseHeader(b *testing.B) {
+	v := ResponseHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashResponsePayload(t *testing.T) {
+	v := ResponsePayload{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashResponsePayload(b *testing.B) {
+	v := ResponsePayload{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgResponsePayload(b *testing.B) {
+	v := ResponsePayload{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashResponseRow(t *testing.T) {
+	v := ResponseRow{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashResponseRow(b *testing.B) {
+	v := ResponseRow{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgResponseRow(b *testing.B) {
+	v := ResponseRow{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashSignedResponseHeader(t *testing.T) {
+	v := SignedResponseHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashSignedResponseHeader(b *testing.B) {
+	v := SignedResponseHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgSignedResponseHeader(b *testing.B) {
+	v := SignedResponseHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
diff --git a/worker/types/types_test.go b/worker/otypes/types_test.go
similarity index 99%
rename from worker/types/types_test.go
rename to worker/otypes/types_test.go
index 89996e21b..aa498a453 100644
--- a/worker/types/types_test.go
+++ b/worker/otypes/types_test.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"testing"
diff --git a/worker/types/update_service_type.go b/worker/otypes/update_service_type.go
similarity index 99%
rename from worker/types/update_service_type.go
rename to worker/otypes/update_service_type.go
index 7d8689afa..24c83c49b 100644
--- a/worker/types/update_service_type.go
+++ b/worker/otypes/update_service_type.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
diff --git a/worker/types/update_service_type_gen.go b/worker/otypes/update_service_type_gen.go
similarity index 99%
rename from worker/types/update_service_type_gen.go
rename to worker/otypes/update_service_type_gen.go
index c92211de3..e48777622 100644
--- a/worker/types/update_service_type_gen.go
+++ b/worker/otypes/update_service_type_gen.go
@@ -1,4 +1,4 @@
-package types
+package otypes
 
 // Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
 
diff --git a/worker/otypes/update_service_type_gen_test.go b/worker/otypes/update_service_type_gen_test.go
new file mode 100644
index 000000000..d78a63158
--- /dev/null
+++ b/worker/otypes/update_service_type_gen_test.go
@@ -0,0 +1,158 @@
+package otypes
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/binary"
+	"testing"
+)
+
+func TestMarshalHashSignedUpdateServiceHeader(t *testing.T) {
+	v := SignedUpdateServiceHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashSignedUpdateServiceHeader(b *testing.B) {
+	v := SignedUpdateServiceHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgSignedUpdateServiceHeader(b *testing.B) {
+	v := SignedUpdateServiceHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashUpdateService(t *testing.T) {
+	v := UpdateService{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashUpdateService(b *testing.B) {
+	v := UpdateService{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgUpdateService(b *testing.B) {
+	v := UpdateService{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashUpdateServiceHeader(t *testing.T) {
+	v := UpdateServiceHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashUpdateServiceHeader(b *testing.B) {
+	v := UpdateServiceHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgUpdateServiceHeader(b *testing.B) {
+	v := UpdateServiceHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashUpdateServiceResponse(t *testing.T) {
+	v := UpdateServiceResponse{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashUpdateServiceResponse(b *testing.B) {
+	v := UpdateServiceResponse{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgUpdateServiceResponse(b *testing.B) {
+	v := UpdateServiceResponse{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
diff --git a/worker/types/util.go b/worker/otypes/util.go
similarity index 98%
rename from worker/types/util.go
rename to worker/otypes/util.go
index a049bc07b..0108aec1e 100644
--- a/worker/types/util.go
+++ b/worker/otypes/util.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package types
+package otypes
 
 import (
 	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
diff --git a/xenomint/chain.go b/xenomint/chain.go
new file mode 100644
index 000000000..5b24c5956
--- /dev/null
+++ b/xenomint/chain.go
@@ -0,0 +1,101 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xenomint
+
+import (
+	ca "github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/types"
+	xi "github.com/CovenantSQL/CovenantSQL/xenomint/interfaces"
+	xs "github.com/CovenantSQL/CovenantSQL/xenomint/sqlite"
+	xt "github.com/CovenantSQL/CovenantSQL/xenomint/types"
+)
+
+const (
+	inCommandBufferLength  = 100000
+	outCommandBufferLength = 100000
+)
+
+type applyRequest struct {
+	request  *types.Request
+	response *types.Response
+}
+
+type blockNode struct {
+	parent *blockNode
+	// Cached block fields
+	hash   hash.Hash
+	count  int32
+	height int32
+	// Cached block object, may be nil
+	block *xt.Block
+}
+
+// Chain defines the xenomint chain structure.
+type Chain struct {
+	state *State
+	// Cached fields
+	priv *ca.PrivateKey
+}
+
+// NewChain returns new chain instance.
+func NewChain(filename string) (c *Chain, err error) {
+	var (
+		strg  xi.Storage
+		state *State
+		priv  *ca.PrivateKey
+	)
+	// generate empty nodeId
+	nodeID := proto.NodeID("0000000000000000000000000000000000000000000000000000000000000000")
+
+	// TODO(leventeliu): add multiple storage engine support.
+	if strg, err = xs.NewSqlite(filename); err != nil {
+		return
+	}
+	if state, err = NewState(nodeID, strg); err != nil {
+		return
+	}
+	if priv, err = kms.GetLocalPrivateKey(); err != nil {
+		return
+	}
+	c = &Chain{
+		state: state,
+		priv:  priv,
+	}
+	return
+}
+
+// Query queries req from local chain state and returns the query results in resp.
+func (c *Chain) Query(req *types.Request) (resp *types.Response, err error) {
+	var ref *QueryTracker
+	if ref, resp, err = c.state.Query(req); err != nil {
+		return
+	}
+	if err = resp.Sign(c.priv); err != nil {
+		return
+	}
+	ref.UpdateResp(resp)
+	return
+}
+
+// Stop stops chain workers and RPC service.
+func (c *Chain) Stop() (err error) {
+	// Close all opened resources
+	return c.state.Close(true)
+}
diff --git a/xenomint/chain_test.go b/xenomint/chain_test.go
new file mode 100644
index 000000000..a20fa4fa1
--- /dev/null
+++ b/xenomint/chain_test.go
@@ -0,0 +1,170 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xenomint
+
+import (
+	"database/sql"
+	"fmt"
+	"math/rand"
+	"os"
+	"path"
+	"testing"
+
+	ca "github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
+	"github.com/CovenantSQL/CovenantSQL/types"
+)
+
+func setupBenchmarkChain(b *testing.B) (c *Chain, n int, r []*types.Request) {
+	// Setup chain state
+	var (
+		fl   = path.Join(testingDataDir, b.Name())
+		err  error
+		stmt *sql.Stmt
+	)
+	if c, err = NewChain(fmt.Sprint("file:", fl)); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	if _, err = c.state.strg.Writer().Exec(
+		`CREATE TABLE "bench" ("k" INT, "v1" TEXT, "v2" TEXT, "v3" TEXT, PRIMARY KEY("k"))`,
+	); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	if stmt, err = c.state.strg.Writer().Prepare(
+		`INSERT INTO "bench" VALUES (?, ?, ?, ?)`,
+	); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	for i := 0; i < benchmarkKeySpace; i++ {
+		var (
+			vals [benchmarkVNum][benchmarkVLen]byte
+			args [benchmarkVNum + 1]interface{}
+		)
+		args[0] = i
+		for i := range vals {
+			rand.Read(vals[i][:])
+			args[i+1] = string(vals[i][:])
+		}
+		if _, err = stmt.Exec(args[:]...); err != nil {
+			b.Fatalf("Failed to setup bench environment: %v", err)
+		}
+	}
+	n = benchmarkKeySpace
+	// Setup query requests
+	var (
+		sel = `SELECT "v1", "v2", "v3" FROM "bench" WHERE "k"=?`
+		ins = `INSERT INTO "bench" VALUES (?, ?, ?, ?)
+	ON CONFLICT("k") DO UPDATE SET
+		"v1"="excluded"."v1",
+		"v2"="excluded"."v2",
+		"v3"="excluded"."v3"
+`
+		priv *ca.PrivateKey
+		src  = make([][]interface{}, benchmarkKeySpace)
+	)
+	if priv, err = kms.GetLocalPrivateKey(); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	r = make([]*types.Request, 2*benchmarkKeySpace)
+	// Read query key space [0, n-1]
+	for i := 0; i < benchmarkKeySpace; i++ {
+		r[i] = buildRequest(types.ReadQuery, []types.Query{
+			buildQuery(sel, i),
+		})
+		if err = r[i].Sign(priv); err != nil {
+			b.Fatalf("Failed to setup bench environment: %v", err)
+		}
+	}
+	// Write query key space [n, 2n-1]
+	for i := range src {
+		var vals [benchmarkVNum][benchmarkVLen]byte
+		src[i] = make([]interface{}, benchmarkVNum+1)
+		src[i][0] = i + benchmarkKeySpace
+		for j := range vals {
+			rand.Read(vals[j][:])
+			src[i][j+1] = string(vals[j][:])
+		}
+	}
+	for i := 0; i < benchmarkKeySpace; i++ {
+		r[benchmarkKeySpace+i] = buildRequest(types.WriteQuery, []types.Query{
+			buildQuery(ins, src[i]...),
+		})
+		if err = r[i+benchmarkKeySpace].Sign(priv); err != nil {
+			b.Fatalf("Failed to setup bench environment: %v", err)
+		}
+	}
+
+	b.ResetTimer()
+	return
+}
+
+func teardownBenchmarkChain(b *testing.B, c *Chain) {
+	b.StopTimer()
+
+	var (
+		fl  = path.Join(testingDataDir, b.Name())
+		err error
+	)
+	if err = c.Stop(); err != nil {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+	if err = os.Remove(fl); err != nil {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+	if err = os.Remove(fmt.Sprint(fl, "-shm")); err != nil && !os.IsNotExist(err) {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+	if err = os.Remove(fmt.Sprint(fl, "-wal")); err != nil && !os.IsNotExist(err) {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+}
+
+func BenchmarkChainParallelWrite(b *testing.B) {
+	var c, n, r = setupBenchmarkChain(b)
+	b.RunParallel(func(pb *testing.PB) {
+		var err error
+		for i := 0; pb.Next(); i++ {
+			if _, err = c.Query(r[n+rand.Intn(n)]); err != nil {
+				b.Fatalf("Failed to execute: %v", err)
+			}
+			if (i+1)%benchmarkQueriesPerBlock == 0 {
+				if err = c.state.commit(); err != nil {
+					b.Fatalf("Failed to commit block: %v", err)
+				}
+			}
+		}
+	})
+	teardownBenchmarkChain(b, c)
+}
+
+func BenchmarkChainParallelMixRW(b *testing.B) {
+	var c, n, r = setupBenchmarkChain(b)
+	b.RunParallel(func(pb *testing.PB) {
+		var err error
+		for i := 0; pb.Next(); i++ {
+			if _, err = c.Query(r[rand.Intn(2*n)]); err != nil {
+				b.Fatalf("Failed to execute: %v", err)
+			}
+			if (i+1)%benchmarkQueriesPerBlock == 0 {
+				if err = c.state.commit(); err != nil {
+					b.Fatalf("Failed to commit block: %v", err)
+				}
+			}
+		}
+	})
+	teardownBenchmarkChain(b, c)
+}
diff --git a/xenomint/doc.go b/xenomint/doc.go
new file mode 100644
index 000000000..3ee1ded09
--- /dev/null
+++ b/xenomint/doc.go
@@ -0,0 +1,18 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Package xenomint provides an eventual consistency implementation of the blockchain database.
+package xenomint
diff --git a/xenomint/errors.go b/xenomint/errors.go
new file mode 100644
index 000000000..725b140cb
--- /dev/null
+++ b/xenomint/errors.go
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xenomint
+
+import (
+	"errors"
+)
+
+var (
+	// ErrMissingParent indicates the parent of the current query attempt is missing.
+	ErrMissingParent = errors.New("query missing parent")
+	// ErrInvalidRequest indicates the query is invalid.
+	ErrInvalidRequest = errors.New("invalid request")
+	// ErrQueryExists indicates the query already exists in pool.
+	ErrQueryExists = errors.New("query already exists")
+	// ErrStateClosed indicates the state is closed.
+	ErrStateClosed = errors.New("state is closed")
+	// ErrQueryConflict indicates the there is a conflict on query replay.
+	ErrQueryConflict = errors.New("query conflict")
+	// ErrLocalBehindRemote indicates the local state is behind the remote.
+	ErrLocalBehindRemote = errors.New("local state is behind the remote")
+	// ErrMuxServiceNotFound indicates that the multiplexing service endpoint is not found.
+	ErrMuxServiceNotFound = errors.New("mux service not found")
+)
diff --git a/chain/interfaces/doc.go b/xenomint/interfaces/doc.go
similarity index 88%
rename from chain/interfaces/doc.go
rename to xenomint/interfaces/doc.go
index 222335fed..c873b128c 100644
--- a/chain/interfaces/doc.go
+++ b/xenomint/interfaces/doc.go
@@ -14,5 +14,5 @@
  * limitations under the License.
  */
 
-// Package interfaces defines commonly used interfaces for block chain.
+// Package interfaces defines common used interfaces of the xenomint package.
 package interfaces
diff --git a/xenomint/interfaces/interfaces.go b/xenomint/interfaces/interfaces.go
new file mode 100644
index 000000000..17427cde9
--- /dev/null
+++ b/xenomint/interfaces/interfaces.go
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package interfaces
+
+import (
+	"database/sql"
+)
+
+// Storage is the interface implemented by an object that returns standard *sql.DB as DirtyReader,
+// Reader, or Writer and can be closed by Close.
+type Storage interface {
+	DirtyReader() *sql.DB
+	Reader() *sql.DB
+	Writer() *sql.DB
+	Close() error
+}
diff --git a/xenomint/mux.go b/xenomint/mux.go
new file mode 100644
index 000000000..b1bd308ee
--- /dev/null
+++ b/xenomint/mux.go
@@ -0,0 +1,124 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xenomint
+
+import (
+	//"context"
+	//"runtime/trace"
+	"sync"
+
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/rpc"
+	"github.com/CovenantSQL/CovenantSQL/types"
+)
+
+// MuxService defines multiplexing service of xenomint chain.
+type MuxService struct {
+	ServiceName string
+	// serviceMap maps DatabaseID to *Chain.
+	serviceMap sync.Map
+}
+
+// NewMuxService returns a new MuxService instance and registers it to server.
+func NewMuxService(name string, server *rpc.Server) (service *MuxService, err error) {
+	var s = &MuxService{
+		ServiceName: name,
+	}
+	if err = server.RegisterService(name, s); err != nil {
+		return
+	}
+	service = s
+	return
+}
+
+func (s *MuxService) register(id proto.DatabaseID, c *Chain) {
+	s.serviceMap.Store(id, c)
+}
+
+func (s *MuxService) unregister(id proto.DatabaseID) {
+	s.serviceMap.Delete(id)
+}
+
+func (s *MuxService) route(id proto.DatabaseID) (c *Chain, err error) {
+	var (
+		i  interface{}
+		ok bool
+	)
+	if i, ok = s.serviceMap.Load(id); !ok {
+		err = ErrMuxServiceNotFound
+		return
+	}
+	if c, ok = i.(*Chain); !ok {
+		err = ErrMuxServiceNotFound
+		return
+	}
+	return
+}
+
+// MuxQueryRequest defines a request of the Query RPC method.
+type MuxQueryRequest struct {
+	proto.DatabaseID
+	proto.Envelope
+	Request *types.Request
+}
+
+// MuxQueryResponse defines a response of the Query RPC method.
+type MuxQueryResponse struct {
+	proto.DatabaseID
+	proto.Envelope
+	Response *types.Response
+}
+
+// Query is the RPC method to process database query on mux service.
+func (s *MuxService) Query(req *MuxQueryRequest, resp *MuxQueryResponse) (err error) {
+	//var ctx, task = trace.NewTask(context.Background(), "MuxService.Query")
+	//defer task.End()
+	//defer trace.StartRegion(ctx, "Total").End()
+	var (
+		c *Chain
+		r *types.Response
+	)
+	if c, err = s.route(req.DatabaseID); err != nil {
+		return
+	}
+	if r, err = c.Query(req.Request); err != nil {
+		return
+	}
+	resp = &MuxQueryResponse{
+		Envelope:   req.Envelope,
+		DatabaseID: req.DatabaseID,
+		Response:   r,
+	}
+	return
+}
+
+// MuxLeaderCommitRequest a request of the MuxLeaderCommitResponse RPC method.
+type MuxLeaderCommitRequest struct {
+	proto.DatabaseID
+	proto.Envelope
+	// Height is the expected block height of this commit.
+	Height int32
+}
+
+// MuxLeaderCommitResponse a response of the MuxLeaderCommitResponse RPC method.
+type MuxLeaderCommitResponse struct {
+	proto.DatabaseID
+	proto.Envelope
+	// Height is the expected block height of this commit.
+	Height int32
+	Offset uint64
+}
diff --git a/xenomint/mux_test.go b/xenomint/mux_test.go
new file mode 100644
index 000000000..e4385ac5a
--- /dev/null
+++ b/xenomint/mux_test.go
@@ -0,0 +1,289 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xenomint
+
+import (
+	"database/sql"
+	"fmt"
+	"math/rand"
+	"os"
+	"path"
+	"strings"
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/conf"
+	con "github.com/CovenantSQL/CovenantSQL/consistent"
+	ca "github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/route"
+	"github.com/CovenantSQL/CovenantSQL/rpc"
+	"github.com/CovenantSQL/CovenantSQL/types"
+)
+
+type nodeRPCInfo struct {
+	node   proto.Node
+	server *rpc.Server
+}
+
+func setupBenchmarkMuxParallel(b *testing.B) (
+	bp, miner *nodeRPCInfo, ms *MuxService, r []*MuxQueryRequest,
+) {
+	var (
+		priv       *ca.PrivateKey
+		nis        []proto.Node
+		dht        *route.DHTService
+		bpSv, mnSv *rpc.Server
+		err        error
+	)
+	// Use testing private key to create several nodes
+	if priv, err = kms.GetLocalPrivateKey(); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	if nis, err = createNodesWithPublicKey(priv.PubKey(), testingNonceDifficulty, 3); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	} else if l := len(nis); l != 3 {
+		b.Fatalf("Failed to setup bench environment: unexpected length %d", l)
+	}
+	// Setup block producer RPC and register server address
+	bpSv = rpc.NewServer()
+	if err = bpSv.InitRPCServer(
+		"localhost:0", testingPrivateKeyFile, testingMasterKey,
+	); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	nis[0].Addr = bpSv.Listener.Addr().String()
+	nis[0].Role = proto.Leader
+	// Setup miner RPC and register server address
+	mnSv = rpc.NewServer()
+	if err = mnSv.InitRPCServer(
+		"localhost:0", testingPrivateKeyFile, testingMasterKey,
+	); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	nis[1].Addr = mnSv.Listener.Addr().String()
+	nis[1].Role = proto.Miner
+	// Setup client
+	nis[2].Role = proto.Client
+	// Setup global config
+	conf.GConf = &conf.Config{
+		IsTestMode:          true,
+		GenerateKeyPair:     false,
+		MinNodeIDDifficulty: testingNonceDifficulty,
+		BP: &conf.BPInfo{
+			PublicKey: priv.PubKey(),
+			NodeID:    nis[0].ID,
+			Nonce:     nis[0].Nonce,
+		},
+		KnownNodes: nis,
+	}
+	// Register DHT service, this will also initialize the public key store
+	if dht, err = route.NewDHTService(
+		testingPublicKeyStoreFile, &con.KMSStorage{}, true,
+	); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	} else if err = bpSv.RegisterService(route.DHTRPCName, dht); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	kms.SetLocalNodeIDNonce(nis[2].ID.ToRawNodeID().CloneBytes(), &nis[2].Nonce)
+	for i := range nis {
+		route.SetNodeAddrCache(nis[i].ID.ToRawNodeID(), nis[i].Addr)
+		kms.SetNode(&nis[i])
+	}
+	// Register mux service
+	if ms, err = NewMuxService(benchmarkRPCName, mnSv); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+
+	// Setup query requests
+	var (
+		sel = `SELECT "v1", "v2", "v3" FROM "bench" WHERE "k"=?`
+		ins = `INSERT INTO "bench" VALUES (?, ?, ?, ?)
+	ON CONFLICT("k") DO UPDATE SET
+		"v1"="excluded"."v1",
+		"v2"="excluded"."v2",
+		"v3"="excluded"."v3"
+`
+		src = make([][]interface{}, benchmarkKeySpace)
+	)
+	r = make([]*MuxQueryRequest, 2*benchmarkKeySpace)
+	// Read query key space [0, n-1]
+	for i := 0; i < benchmarkKeySpace; i++ {
+		var req = buildRequest(types.ReadQuery, []types.Query{
+			buildQuery(sel, i),
+		})
+		if err = req.Sign(priv); err != nil {
+			b.Fatalf("Failed to setup bench environment: %v", err)
+		}
+		r[i] = &MuxQueryRequest{
+			DatabaseID: benchmarkDatabaseID,
+			Request:    req,
+		}
+	}
+	// Write query key space [n, 2n-1]
+	for i := range src {
+		var vals [benchmarkVNum][benchmarkVLen]byte
+		src[i] = make([]interface{}, benchmarkVNum+1)
+		src[i][0] = i + benchmarkKeySpace
+		for j := range vals {
+			rand.Read(vals[j][:])
+			src[i][j+1] = string(vals[j][:])
+		}
+	}
+	for i := 0; i < benchmarkKeySpace; i++ {
+		var req = buildRequest(types.WriteQuery, []types.Query{
+			buildQuery(ins, src[i]...),
+		})
+		if err = req.Sign(priv); err != nil {
+			b.Fatalf("Failed to setup bench environment: %v", err)
+		}
+		r[benchmarkKeySpace+i] = &MuxQueryRequest{
+			DatabaseID: benchmarkDatabaseID,
+			Request:    req,
+		}
+	}
+
+	bp = &nodeRPCInfo{
+		node:   nis[0],
+		server: bpSv,
+	}
+	miner = &nodeRPCInfo{
+		node:   nis[1],
+		server: mnSv,
+	}
+
+	go bpSv.Serve()
+	go mnSv.Serve()
+	//ca.BypassSignature = true
+	return
+}
+
+func teardownBenchmarkMuxParallel(b *testing.B, bpSv, mnSv *rpc.Server) {
+	//ca.BypassSignature = false
+	mnSv.Stop()
+	bpSv.Stop()
+}
+
+func setupSubBenchmarkMuxParallel(b *testing.B, ms *MuxService) (c *Chain) {
+	// Setup chain state
+	var (
+		fl   = path.Join(testingDataDir, strings.Replace(b.Name(), "/", "-", -1))
+		err  error
+		stmt *sql.Stmt
+	)
+	if c, err = NewChain(fmt.Sprint("file:", fl)); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	if _, err = c.state.strg.Writer().Exec(
+		`CREATE TABLE "bench" ("k" INT, "v1" TEXT, "v2" TEXT, "v3" TEXT, PRIMARY KEY("k"))`,
+	); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	if stmt, err = c.state.strg.Writer().Prepare(
+		`INSERT INTO "bench" VALUES (?, ?, ?, ?)`,
+	); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	for i := 0; i < benchmarkKeySpace; i++ {
+		var (
+			vals [benchmarkVNum][benchmarkVLen]byte
+			args [benchmarkVNum + 1]interface{}
+		)
+		args[0] = i
+		for i := range vals {
+			rand.Read(vals[i][:])
+			args[i+1] = string(vals[i][:])
+		}
+		if _, err = stmt.Exec(args[:]...); err != nil {
+			b.Fatalf("Failed to setup bench environment: %v", err)
+		}
+	}
+	ms.register(benchmarkDatabaseID, c)
+
+	b.ResetTimer()
+	return
+}
+
+func teardownSubBenchmarkMuxParallel(b *testing.B, ms *MuxService) {
+	b.StopTimer()
+
+	var (
+		fl  = path.Join(testingDataDir, strings.Replace(b.Name(), "/", "-", -1))
+		err error
+		c   *Chain
+	)
+	// Stop RPC server
+	if c, err = ms.route(benchmarkDatabaseID); err != nil {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+	ms.unregister(benchmarkDatabaseID)
+	// Close chain
+	if err = c.Stop(); err != nil {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+	if err = os.Remove(fl); err != nil {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+	if err = os.Remove(fmt.Sprint(fl, "-shm")); err != nil && !os.IsNotExist(err) {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+	if err = os.Remove(fmt.Sprint(fl, "-wal")); err != nil && !os.IsNotExist(err) {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+}
+
+func BenchmarkMuxParallel(b *testing.B) {
+	var bp, s, ms, r = setupBenchmarkMuxParallel(b)
+	defer teardownBenchmarkMuxParallel(b, bp.server, s.server)
+	var benchmarks = []struct {
+		name    string
+		randkey func(n int) int // Returns a random key from given key space
+	}{
+		{
+			name:    "Write",
+			randkey: func(n int) int { return n + rand.Intn(n) },
+		}, {
+			name:    "MixRW",
+			randkey: func(n int) int { return rand.Intn(2 * n) },
+		},
+	}
+	for _, bm := range benchmarks {
+		b.Run(bm.name, func(b *testing.B) {
+			var c = setupSubBenchmarkMuxParallel(b, ms)
+			defer teardownSubBenchmarkMuxParallel(b, ms)
+			b.RunParallel(func(pb *testing.PB) {
+				var (
+					err    error
+					method = fmt.Sprintf("%s.%s", benchmarkRPCName, "Query")
+					caller = rpc.NewPersistentCaller(s.node.ID)
+				)
+				for i := 0; pb.Next(); i++ {
+					if err = caller.Call(
+						method, &r[bm.randkey(benchmarkKeySpace)], &MuxQueryResponse{},
+					); err != nil {
+						b.Fatalf("Failed to execute: %v", err)
+					}
+					if (i+1)%benchmarkQueriesPerBlock == 0 {
+						if err = c.state.commit(); err != nil {
+							b.Fatalf("Failed to commit block: %v", err)
+						}
+					}
+				}
+			})
+		})
+	}
+}
diff --git a/xenomint/pool.go b/xenomint/pool.go
new file mode 100644
index 000000000..38a1f6511
--- /dev/null
+++ b/xenomint/pool.go
@@ -0,0 +1,141 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xenomint
+
+import (
+	"sync"
+	"sync/atomic"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/types"
+)
+
+// QueryTracker defines an object to track query as a request - response pair.
+type QueryTracker struct {
+	sync.RWMutex
+	Req  *types.Request
+	Resp *types.Response
+}
+
+// UpdateResp updates response of the QueryTracker within locking scope.
+func (q *QueryTracker) UpdateResp(resp *types.Response) {
+	q.Lock()
+	defer q.Unlock()
+	q.Resp = resp
+}
+
+// Ready reports whether the query is ready for block producing. It is assumed that all objects
+// should be ready shortly.
+func (q *QueryTracker) Ready() bool {
+	q.RLock()
+	defer q.RUnlock()
+	return q.Resp != nil
+}
+
+type pool struct {
+	// Failed queries: hash => Request
+	failed map[hash.Hash]*types.Request
+	// Succeeded queries and their index
+	queries []*QueryTracker
+	index   map[uint64]int
+	// Atomic counters for stats
+	failedRequestCount int32
+	trackerCount       int32
+}
+
+func newPool() *pool {
+	return &pool{
+		failed:  make(map[hash.Hash]*types.Request),
+		queries: make([]*QueryTracker, 0),
+		index:   make(map[uint64]int),
+	}
+}
+
+func (p *pool) enqueue(sp uint64, q *QueryTracker) {
+	var pos = len(p.queries)
+	p.queries = append(p.queries, q)
+	p.index[sp] = pos
+	atomic.StoreInt32(&p.trackerCount, int32(len(p.queries)))
+	return
+}
+
+func (p *pool) setFailed(req *types.Request) {
+	p.failed[req.Header.Hash()] = req
+	atomic.StoreInt32(&p.failedRequestCount, int32(len(p.failed)))
+}
+
+func (p *pool) failedList() (reqs []*types.Request) {
+	reqs = make([]*types.Request, 0, len(p.failed))
+	for _, v := range p.failed {
+		reqs = append(reqs, v)
+	}
+	return
+}
+
+func (p *pool) removeFailed(req *types.Request) {
+	delete(p.failed, req.Header.Hash())
+	atomic.StoreInt32(&p.failedRequestCount, int32(len(p.failed)))
+}
+
+func (p *pool) match(sp uint64, req *types.Request) bool {
+	var (
+		pos int
+		ok  bool
+	)
+	if pos, ok = p.index[sp]; !ok {
+		return false
+	}
+	if p.queries[pos].Req.Header.Hash() != req.Header.Hash() {
+		return false
+	}
+	return true
+}
+
+func (p *pool) matchLast(sp uint64) bool {
+	var (
+		pos int
+		ok  bool
+	)
+	if pos, ok = p.index[sp]; !ok {
+		return false
+	}
+	if pos != len(p.queries)-1 {
+		return false
+	}
+	return true
+}
+
+func (p *pool) truncate(sp uint64) {
+	var (
+		pos int
+		ok  bool
+		ni  map[uint64]int
+	)
+	if pos, ok = p.index[sp]; !ok {
+		return
+	}
+	// Rebuild index
+	ni = make(map[uint64]int)
+	for k, v := range p.index {
+		if k > sp {
+			ni[k] = v - (pos + 1)
+		}
+	}
+	p.index = ni
+	p.queries = p.queries[pos+1:]
+	atomic.StoreInt32(&p.trackerCount, int32(len(p.queries)))
+}
diff --git a/xenomint/pool_test.go b/xenomint/pool_test.go
new file mode 100644
index 000000000..f68ede27a
--- /dev/null
+++ b/xenomint/pool_test.go
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xenomint
diff --git a/xenomint/sqlite/doc.go b/xenomint/sqlite/doc.go
new file mode 100644
index 000000000..bd513d369
--- /dev/null
+++ b/xenomint/sqlite/doc.go
@@ -0,0 +1,18 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Package sqlite introduces a sqlite3 implementation of the xenomint/interfaces.Storage interface.
+package sqlite
diff --git a/xenomint/sqlite/sqlite.go b/xenomint/sqlite/sqlite.go
new file mode 100644
index 000000000..0ea8bf846
--- /dev/null
+++ b/xenomint/sqlite/sqlite.go
@@ -0,0 +1,120 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sqlite
+
+import (
+	"database/sql"
+
+	"github.com/CovenantSQL/CovenantSQL/storage"
+	"github.com/CovenantSQL/go-sqlite3-encrypt"
+)
+
+const (
+	serializableDriver = "sqlite3"
+	dirtyReadDriver    = "sqlite3-dirty-reader"
+)
+
+func init() {
+	sql.Register(dirtyReadDriver, &sqlite3.SQLiteDriver{
+		ConnectHook: func(c *sqlite3.SQLiteConn) (err error) {
+			if _, err = c.Exec("PRAGMA read_uncommitted=1", nil); err != nil {
+				return
+			}
+			return
+		},
+	})
+}
+
+// SQLite3 is the sqlite3 implementation of the xenomint/interfaces.Storage interface.
+type SQLite3 struct {
+	filename    string
+	dirtyReader *sql.DB
+	reader      *sql.DB
+	writer      *sql.DB
+}
+
+// NewSqlite returns a new SQLite3 instance attached to filename.
+func NewSqlite(filename string) (s *SQLite3, err error) {
+	var (
+		instance  = &SQLite3{filename: filename}
+		shmRODSN  string
+		privRODSN string
+		shmRWDSN  string
+		dsn       *storage.DSN
+	)
+
+	if dsn, err = storage.NewDSN(filename); err != nil {
+		return
+	}
+
+	dsnRO := dsn.Clone()
+	dsnRO.AddParam("_journal_mode", "WAL")
+	dsnRO.AddParam("_query_only", "on")
+	dsnRO.AddParam("cache", "shared")
+	shmRODSN = dsnRO.Format()
+
+	dsnPrivRO := dsn.Clone()
+	dsnPrivRO.AddParam("_journal_mode", "WAL")
+	dsnPrivRO.AddParam("_query_only", "on")
+	privRODSN = dsnPrivRO.Format()
+
+	dsnSHMRW := dsn.Clone()
+	dsnSHMRW.AddParam("_journal_mode", "WAL")
+	dsnSHMRW.AddParam("cache", "shared")
+	shmRWDSN = dsnSHMRW.Format()
+
+	if instance.dirtyReader, err = sql.Open(dirtyReadDriver, shmRODSN); err != nil {
+		return
+	}
+	if instance.reader, err = sql.Open(serializableDriver, privRODSN); err != nil {
+		return
+	}
+	if instance.writer, err = sql.Open(serializableDriver, shmRWDSN); err != nil {
+		return
+	}
+	s = instance
+	return
+}
+
+// DirtyReader implements DirtyReader method of the xenomint/interfaces.Storage interface.
+func (s *SQLite3) DirtyReader() *sql.DB {
+	return s.dirtyReader
+}
+
+// Reader implements Reader method of the xenomint/interfaces.Storage interface.
+func (s *SQLite3) Reader() *sql.DB {
+	return s.reader
+}
+
+// Writer implements Writer method of the xenomint/interfaces.Storage interface.
+func (s *SQLite3) Writer() *sql.DB {
+	return s.writer
+}
+
+// Close implements Close method of the xenomint/interfaces.Storage interface.
+func (s *SQLite3) Close() (err error) {
+	if err = s.dirtyReader.Close(); err != nil {
+		return
+	}
+	if err = s.reader.Close(); err != nil {
+		return
+	}
+	if err = s.writer.Close(); err != nil {
+		return
+	}
+	return
+}
diff --git a/xenomint/sqlite/sqlite_test.go b/xenomint/sqlite/sqlite_test.go
new file mode 100644
index 000000000..6288b8f51
--- /dev/null
+++ b/xenomint/sqlite/sqlite_test.go
@@ -0,0 +1,1072 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sqlite
+
+import (
+	"database/sql"
+	"fmt"
+	"math/rand"
+	"os"
+	"path"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	xi "github.com/CovenantSQL/CovenantSQL/xenomint/interfaces"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestStorage(t *testing.T) {
+	Convey("Given a sqlite storage implementation", t, func() {
+		const passes = 1000
+		var (
+			fl  = path.Join(testingDataDir, t.Name())
+			st  xi.Storage
+			err error
+		)
+		st, err = NewSqlite(fmt.Sprint("file:", fl))
+		So(err, ShouldBeNil)
+		So(st, ShouldNotBeNil)
+		Reset(func() {
+			// Clean database file after each pass
+			err = st.Close()
+			So(err, ShouldBeNil)
+			err = os.Remove(fl)
+			So(err, ShouldBeNil)
+			err = os.Remove(fmt.Sprint(fl, "-shm"))
+			So(err == nil || os.IsNotExist(err), ShouldBeTrue)
+			err = os.Remove(fmt.Sprint(fl, "-wal"))
+			So(err == nil || os.IsNotExist(err), ShouldBeTrue)
+		})
+		Convey("When a basic KV table is created", func(c C) {
+			// Create basic table for testing
+			_, err = st.Writer().Exec(`CREATE TABLE "t1" ("k" INT, "v" TEXT, PRIMARY KEY("k"))`)
+			So(err, ShouldBeNil)
+			Convey("When storage is closed", func() {
+				err = st.Close()
+				So(err, ShouldBeNil)
+				Convey("The storage should report error for any incoming query", func() {
+					err = st.DirtyReader().QueryRow(`SELECT "v" FROM "t1" WHERE "k"=?`, 1).Scan(nil)
+					So(err, ShouldNotBeNil)
+					So(err.Error(), ShouldEqual, "sql: database is closed")
+					err = st.Reader().QueryRow(`SELECT "v" FROM "t1" WHERE "k"=?`, 1).Scan(nil)
+					So(err, ShouldNotBeNil)
+					So(err.Error(), ShouldEqual, "sql: database is closed")
+					_, err = st.Writer().Exec(`INSERT INTO "t1" ("k", "v") VALUES (?, ?)`, 1, "v1")
+					So(err, ShouldNotBeNil)
+					So(err.Error(), ShouldEqual, "sql: database is closed")
+				})
+			})
+			Convey("The storage should report error when readers attempt to write", func() {
+				_, err = st.DirtyReader().Exec(`INSERT INTO "t1" ("k", "v") VALUES (?, ?)`, 1, "v1")
+				So(err, ShouldNotBeNil)
+				So(err.Error(), ShouldEqual, "attempt to write a readonly database")
+				_, err = st.Reader().Exec(`INSERT INTO "t1" ("k", "v") VALUES (?, ?)`, 1, "v1")
+				So(err, ShouldNotBeNil)
+				So(err.Error(), ShouldEqual, "attempt to write a readonly database")
+			})
+			Convey("The storage should work properly under concurrent reading/writing", func(c C) {
+				var (
+					ec = make(chan error, passes)
+					sc = make(chan struct{})
+					wg = &sync.WaitGroup{}
+
+					abortReaders = func() { close(sc) }
+				)
+				for i := 0; i < passes; i++ {
+					wg.Add(1)
+					go func(k int) {
+						var ticker = time.NewTicker(1 * time.Millisecond)
+						defer func() {
+							ticker.Stop()
+							wg.Done()
+						}()
+						for {
+							select {
+							case <-ticker.C:
+								var (
+									err error
+									v   string
+								)
+								if err = st.Reader().QueryRow(
+									`SELECT "v" FROM "t1" WHERE "k"=?`, k,
+								).Scan(&v); err != sql.ErrNoRows {
+									if err != nil {
+										ec <- err
+									} else {
+										c.Printf("\n        Read pair from t1: k=%d v=%s ", k, v)
+									}
+									return
+								}
+							case <-sc:
+								return
+							}
+						}
+					}(i)
+				}
+				defer func() {
+					wg.Wait()
+					close(ec)
+					var errs = len(ec)
+					for err = range ec {
+						Printf("\n        Get error from channel: %v ", err)
+					}
+					So(errs, ShouldBeZeroValue)
+				}()
+				for i := 0; i < passes; i++ {
+					if _, err = st.Writer().Exec(
+						`INSERT INTO "t1" ("k", "v") VALUES (?, ?)`, i, fmt.Sprintf("v%d", i),
+					); err != nil {
+						abortReaders()
+					}
+					So(err, ShouldBeNil)
+					c.Printf("\n        Write pair to t1: k=%d v=v%d ", i, i)
+				}
+			})
+			Convey("The storage should see uncommitted changes from dirty reader", func(c C) {
+				var (
+					tx *sql.Tx
+					ec = make(chan error, passes)
+					sc = make(chan struct{})
+					wg = &sync.WaitGroup{}
+
+					abortReaders = func() { close(sc) }
+				)
+				// Open transaction
+				tx, err = st.Writer().Begin()
+				So(err, ShouldBeNil)
+				So(tx, ShouldNotBeNil)
+				for i := 0; i < passes; i++ {
+					wg.Add(1)
+					go func(k int) {
+						var ticker = time.NewTicker(1 * time.Millisecond)
+						defer func() {
+							ticker.Stop()
+							wg.Done()
+						}()
+						for {
+							select {
+							case <-ticker.C:
+								var (
+									err error
+									v   string
+								)
+								if err = st.DirtyReader().QueryRow(
+									`SELECT "v" FROM "t1" WHERE "k"=?`, k,
+								).Scan(&v); err != sql.ErrNoRows {
+									if err != nil {
+										ec <- err
+									} else {
+										c.Printf("\n        Dirty read pair from t1: k=%d v=%s ",
+											k, v)
+									}
+									return
+								}
+							case <-sc:
+								return
+							}
+						}
+					}(i)
+				}
+				defer func() {
+					wg.Wait()
+					close(ec)
+					var errs = len(ec)
+					for err = range ec {
+						Printf("\n        Get error from channel: %v ", err)
+					}
+					So(errs, ShouldBeZeroValue)
+					err = tx.Commit()
+					So(err, ShouldBeNil)
+				}()
+				for i := 0; i < passes; i++ {
+					var (
+						v  = fmt.Sprintf("v%d", i)
+						rv string
+					)
+					if _, err = tx.Exec(
+						`INSERT INTO "t1" ("k", "v") VALUES (?, ?)`, i, v,
+					); err != nil {
+						abortReaders()
+					}
+					So(err, ShouldBeNil)
+					// No isolation between operations on the same database connection
+					if err = tx.QueryRow(
+						`SELECT "v" FROM "t1" WHERE "k"=?`, i,
+					).Scan(&rv); err != nil || rv != v {
+						abortReaders()
+					}
+					So(err, ShouldBeNil)
+					So(rv, ShouldEqual, v)
+					c.Printf("\n        Write pair to t1 in transaction: k=%d v=%s ", i, v)
+				}
+				// Reader connection should not see any uncommitted change
+				for i := 0; i < passes; i++ {
+					err = st.Reader().QueryRow(`SELECT "v" FROM "t1" WHERE "k"=?`, i).Scan(nil)
+					So(err, ShouldEqual, sql.ErrNoRows)
+				}
+			})
+		})
+	})
+}
+
+const (
+	benchmarkQueriesPerTx      = 100
+	benchmarkVNum              = 3
+	benchmarkVLen              = 333
+	benchmarkKeySubspaceLength = 1000000
+
+	benchmarkReservedKeyOffset = iota * benchmarkKeySubspaceLength
+	benchmarkNewKeyOffset
+	benchmarkKeySpace
+)
+
+type keygen interface {
+	next() int
+	reset()
+}
+
+type randKeygen struct {
+	offset int
+	length int
+}
+
+func newRandKeygen(offset, length int) *randKeygen {
+	return &randKeygen{
+		offset: offset,
+		length: length,
+	}
+}
+
+func newIndexRandKeygen(length int) *randKeygen { return newRandKeygen(0, length) }
+
+func (k *randKeygen) next() int { return rand.Intn(k.length) + k.offset }
+func (k *randKeygen) reset()    {}
+
+type permKeygen struct {
+	offset int
+	length int
+	perm   []int
+	pos    int32
+}
+
+func newPermKeygen(offset, length int) *permKeygen {
+	return &permKeygen{
+		offset: offset,
+		length: length,
+		perm:   rand.Perm(length),
+	}
+}
+
+func newIndexPermKeygen(length int) *permKeygen { return newPermKeygen(0, length) }
+
+func (k *permKeygen) next() int {
+	var pos = atomic.AddInt32(&k.pos, 1) - 1
+	if pos >= int32(k.length) {
+		panic("permKeygen: keys have been exhausted")
+	}
+	return k.perm[pos] + k.offset
+}
+
+func (k *permKeygen) reset() { k.pos = 0 }
+
+var (
+	irkg = newIndexRandKeygen(benchmarkKeySubspaceLength)
+	ipkg = newIndexPermKeygen(benchmarkKeySubspaceLength)
+	rrkg = newRandKeygen(benchmarkReservedKeyOffset, benchmarkKeySubspaceLength)
+	nrkg = newRandKeygen(benchmarkNewKeyOffset, benchmarkKeySubspaceLength)
+	trkg = newRandKeygen(0, benchmarkKeySpace)
+)
+
+func setupBenchmarkStorage(b *testing.B) (
+	st xi.Storage,
+	q string, makeDest func() []interface{},
+	e string, src [][]interface{},
+) {
+	// Setup storage
+	var (
+		fl   = path.Join(testingDataDir, b.Name())
+		err  error
+		stmt *sql.Stmt
+	)
+	if st, err = NewSqlite(fmt.Sprint("file:", fl)); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	if _, err = st.Writer().Exec(
+		`CREATE TABLE "t2" ("k" INT, "v1" TEXT, "v2" TEXT, "v3" TEXT, PRIMARY KEY("k"))`,
+	); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	if stmt, err = st.Writer().Prepare(
+		`INSERT INTO "t2" VALUES (?, ?, ?, ?)`,
+	); err != nil {
+		b.Fatalf("Failed to setup bench environment: %v", err)
+	}
+	for i := 0; i < benchmarkKeySubspaceLength; i++ {
+		var (
+			vals [benchmarkVNum][benchmarkVLen]byte
+			args [benchmarkVNum + 1]interface{}
+		)
+		args[0] = benchmarkReservedKeyOffset + i
+		for i := range vals {
+			rand.Read(vals[i][:])
+			args[i+1] = string(vals[i][:])
+		}
+		if _, err = stmt.Exec(args[:]...); err != nil {
+			b.Fatalf("Failed to setup bench environment: %v", err)
+		}
+		if i%10000 == 0 {
+			fmt.Printf("Done setup key at %v\n", i)
+		}
+	}
+	// Setup query string and dest slice
+	q = `SELECT "v1", "v2", "v3" FROM "t2" WHERE "k"=?`
+	makeDest = func() (dest []interface{}) {
+		var outv [benchmarkVNum]string
+		dest = make([]interface{}, benchmarkVNum)
+		for i := range outv {
+			dest[i] = &outv[i]
+		}
+		return
+	}
+	// Setup execute string and src table
+	//
+	// NOTE(leventeliu): allowing IGNORE and REPLACE both have impact on benchmark result,
+	// while UPSERT is the best!
+	//
+	// e = `INSERT OR IGNORE INTO "t2" VALUES (?, ?, ?, ?)`
+	// e = `REPLACE INTO "t2" VALUES (?, ?, ?, ?)`
+	e = `INSERT INTO "t2" VALUES (?, ?, ?, ?)
+	ON CONFLICT("k") DO UPDATE SET
+		"v1"="excluded"."v1",
+		"v2"="excluded"."v2",
+		"v3"="excluded"."v3"
+`
+	src = make([][]interface{}, benchmarkKeySubspaceLength)
+	for i := range src {
+		var vals [benchmarkVNum][benchmarkVLen]byte
+		src[i] = make([]interface{}, benchmarkVNum+1)
+		src[i][0] = benchmarkNewKeyOffset + i
+		for j := range vals {
+			rand.Read(vals[j][:])
+			src[i][j+1] = string(vals[j][:])
+		}
+	}
+
+	return
+}
+
+func teardownBenchmarkStorage(b *testing.B, st xi.Storage) {
+	var (
+		fl  = path.Join(testingDataDir, b.Name())
+		err error
+	)
+	if err = st.Close(); err != nil {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+	if err = os.Remove(fl); err != nil {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+	if err = os.Remove(fmt.Sprint(fl, "-shm")); err != nil && !os.IsNotExist(err) {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+	if err = os.Remove(fmt.Sprint(fl, "-wal")); err != nil && !os.IsNotExist(err) {
+		b.Fatalf("Failed to teardown bench environment: %v", err)
+	}
+}
+
+func setupSubBenchmarkStorage(b *testing.B, st xi.Storage) {
+	// Reset key generators
+	irkg.reset()
+	ipkg.reset()
+	rrkg.reset()
+	nrkg.reset()
+	trkg.reset()
+}
+
+func teardownSubBenchmarkStorage(b *testing.B, st xi.Storage) {
+	var (
+		d   = `DELETE FROM "t2" WHERE "k">=?`
+		err error
+	)
+	if _, err = st.Writer().Exec(d, benchmarkNewKeyOffset); err != nil {
+		b.Fatalf("Failed to teardown sub bench environment: %v", err)
+	}
+}
+
+type benchmarkProfile struct {
+	name   string
+	parall bool
+	proc   func(*testing.B, int)
+	pproc  func(*testing.PB)
+	bg     func(*testing.B, *sync.WaitGroup, <-chan struct{})
+}
+
+func BenchmarkStorage(b *testing.B) {
+	var (
+		st, q, dm, e, src = setupBenchmarkStorage(b)
+
+		tx   *sql.Tx
+		dest = dm()
+		read = func(b *testing.B, conn *sql.DB, dest []interface{}) {
+			var err error
+			if err = conn.QueryRow(q, rrkg.next()).Scan(dest...); err != nil {
+				b.Fatalf("Failed to query values: %v", err)
+			}
+		}
+		readTx = func(b *testing.B, i int, conn *sql.DB, dest []interface{}) {
+			var err error
+			if i%benchmarkQueriesPerTx == 0 {
+				if tx, err = conn.Begin(); err != nil {
+					b.Fatalf("Failed to begin transaction: %v", err)
+				}
+			}
+			// Query in [n, 2n-1] key space
+			if err = tx.QueryRow(q, nrkg.next()).Scan(dest...); err != nil && err != sql.ErrNoRows {
+				b.Fatalf("Failed to query values: %v", err)
+			}
+			if (i+1)%benchmarkQueriesPerTx == 0 || i == b.N-1 {
+				if err = tx.Rollback(); err != nil {
+					b.Fatalf("Failed to close transaction: %v", err)
+				}
+			}
+		}
+		write = func(b *testing.B, conn *sql.DB) {
+			var err error
+			if _, err = conn.Exec(e, src[ipkg.next()]...); err != nil {
+				b.Errorf("Failed to execute: %v", err)
+			}
+		}
+		writeTx = func(b *testing.B, i int, conn *sql.DB) {
+			var err error
+			if i%benchmarkQueriesPerTx == 0 {
+				if tx, err = st.Writer().Begin(); err != nil {
+					b.Errorf("Failed to begin transaction: %v", err)
+				}
+			}
+			if _, err = tx.Exec(e, src[ipkg.next()]...); err != nil {
+				b.Errorf("Failed to execute: %v", err)
+			}
+			if (i+1)%benchmarkQueriesPerTx == 0 || i == b.N-1 {
+				if err = tx.Commit(); err != nil {
+					b.Errorf("Failed to commit transaction: %v", err)
+				}
+			}
+		}
+		mixRW = func(b *testing.B, rconn, wconn *sql.DB, dest []interface{}) {
+			if rand.Int()%2 == 0 {
+				read(b, rconn, dest)
+			} else {
+				write(b, wconn)
+			}
+		}
+
+		bgw = func(b *testing.B, wg *sync.WaitGroup, sc <-chan struct{}) {
+			busyWrite(b, wg, sc, st, ipkg, e, src)
+		}
+		bgbwtx = func(b *testing.B, wg *sync.WaitGroup, sc <-chan struct{}) {
+			busyWriteTx(b, wg, sc, st, ipkg, e, src)
+		}
+		bgiwtx = func(b *testing.B, wg *sync.WaitGroup, sc <-chan struct{}) {
+			idleWriteTx(b, wg, sc, st, ipkg, e, src)
+		}
+
+		pproc = func(pb *testing.PB, proc func()) {
+			for pb.Next() {
+				proc()
+			}
+		}
+
+		profiles = [...]benchmarkProfile{
+			{
+				name: "SequentialDirtyRead",
+				proc: func(b *testing.B, _ int) { read(b, st.DirtyReader(), dest) },
+			}, {
+				name: "SequentialRead",
+				proc: func(b *testing.B, _ int) { read(b, st.Reader(), dest) },
+			}, {
+				name: "SequentialWrite",
+				proc: func(b *testing.B, _ int) { write(b, st.Writer()) },
+			}, {
+				name: "SequentialWriteTx",
+				proc: func(b *testing.B, i int) { writeTx(b, i, st.Writer()) },
+			}, {
+				name: "SequentialMixDRW",
+				proc: func(b *testing.B, _ int) { mixRW(b, st.DirtyReader(), st.Writer(), dest) },
+			}, {
+				name: "SequentialMixRW",
+				proc: func(b *testing.B, _ int) { mixRW(b, st.Reader(), st.Writer(), dest) },
+			}, {
+				name: "SequentialDirtyReadWithBackgroundWriter",
+				proc: func(b *testing.B, _ int) { read(b, st.DirtyReader(), dest) },
+				bg:   bgw,
+			}, {
+				name: "SequentialReadWithBackgroundWriter",
+				proc: func(b *testing.B, _ int) { read(b, st.Reader(), dest) },
+				bg:   bgw,
+			}, {
+				name: "SequentialDirtyReadWithBackgroundBusyTxWriter",
+				proc: func(b *testing.B, _ int) { read(b, st.DirtyReader(), dest) },
+				bg:   bgbwtx,
+			}, {
+				name: "SequentialReadWithBackgroundBusyTxWriter",
+				proc: func(b *testing.B, _ int) { read(b, st.Reader(), dest) },
+				bg:   bgbwtx,
+			}, {
+				name: "SequentialDirtyReadWithBackgroundIdleTxWriter",
+				proc: func(b *testing.B, _ int) { read(b, st.DirtyReader(), dest) },
+				bg:   bgiwtx,
+			}, {
+				name: "SequentialReadWithBackgroundIdleTxWriter",
+				proc: func(b *testing.B, _ int) { read(b, st.Reader(), dest) },
+				bg:   bgiwtx,
+			}, {
+				name: "SequentialDirtyReadTxWithBackgroundWriter",
+				proc: func(b *testing.B, i int) { readTx(b, i, st.DirtyReader(), dest) },
+				bg:   bgw,
+			}, {
+				name: "SequentialReadTxWithBackgroundWriter",
+				proc: func(b *testing.B, i int) { readTx(b, i, st.Reader(), dest) },
+				bg:   bgw,
+			}, {
+				name: "SequentialDirtyReadTxWithBackgroundBusyTxWriter",
+				proc: func(b *testing.B, i int) { readTx(b, i, st.DirtyReader(), dest) },
+				bg:   bgbwtx,
+			}, {
+				name: "SequentialReadTxWithBackgroundBusyTxWriter",
+				proc: func(b *testing.B, i int) { readTx(b, i, st.Reader(), dest) },
+				bg:   bgbwtx,
+			}, {
+				name: "SequentialDirtyReadTxWithBackgroundIdleTxWriter",
+				proc: func(b *testing.B, i int) { readTx(b, i, st.DirtyReader(), dest) },
+				bg:   bgiwtx,
+			}, {
+				name: "SequentialReadTxWithBackgroundIdleTxWriter",
+				proc: func(b *testing.B, i int) { readTx(b, i, st.Reader(), dest) },
+				bg:   bgiwtx,
+			}, {
+				name:   "ParallelDirtyRead",
+				parall: true,
+				pproc: func(pb *testing.PB) {
+					pproc(pb, func() { read(b, st.DirtyReader(), dm()) })
+				},
+			}, {
+				name:   "ParallelRead",
+				parall: true,
+				pproc: func(pb *testing.PB) {
+					pproc(pb, func() { read(b, st.Reader(), dm()) })
+				},
+			}, {
+				name:   "ParallelWrite",
+				parall: true,
+				pproc: func(pb *testing.PB) {
+					pproc(pb, func() { write(b, st.Writer()) })
+				},
+			}, {
+				name:   "ParallelMixDRW",
+				parall: true,
+				pproc: func(pb *testing.PB) {
+					pproc(pb, func() { mixRW(b, st.DirtyReader(), st.Writer(), dm()) })
+				},
+			}, {
+				name:   "ParallelMixRW",
+				parall: true,
+				pproc: func(pb *testing.PB) {
+					pproc(pb, func() { mixRW(b, st.Reader(), st.Writer(), dm()) })
+				},
+			},
+		}
+	)
+	defer teardownBenchmarkStorage(b, st)
+	// Run benchmark profiles
+	for _, v := range profiles {
+		b.Run(v.name, func(b *testing.B) {
+			// Setup environment for sub-benchmark
+			setupSubBenchmarkStorage(b, st)
+			defer teardownSubBenchmarkStorage(b, st)
+			// Start background goroutine
+			var (
+				wg = &sync.WaitGroup{}
+				sc = make(chan struct{})
+			)
+			if v.bg != nil {
+				wg.Add(1)
+				go v.bg(b, wg, sc)
+			}
+			defer func() {
+				close(sc)
+				wg.Wait()
+			}()
+			// Test body
+			b.ResetTimer()
+			if v.parall {
+				// Run parallel
+				b.RunParallel(v.pproc)
+			} else {
+				// Run sequential
+				for i := 0; i < b.N; i++ {
+					v.proc(b, i)
+				}
+			}
+			b.StopTimer()
+		})
+	}
+}
+
+//func BenchmarkStorageSequentialDirtyRead(b *testing.B) {
+//	var (
+//		st, q, dm, _, _ = setupBenchmarkStorage(b)
+//		dest            = dm()
+//		err             error
+//	)
+//	for i := 0; i < b.N; i++ {
+//		if err = st.DirtyReader().QueryRow(q, rrkg.next()).Scan(dest...); err != nil {
+//			b.Fatalf("Failed to query values: %v", err)
+//		}
+//	}
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+//func BenchmarkStoargeSequentialRead(b *testing.B) {
+//	var (
+//		st, q, dm, _, _ = setupBenchmarkStorage(b)
+//		dest            = dm()
+//		err             error
+//	)
+//	for i := 0; i < b.N; i++ {
+//		if err = st.Reader().QueryRow(q, rrkg.next()).Scan(dest...); err != nil {
+//			b.Fatalf("Failed to query values: %v", err)
+//		}
+//	}
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+//func BenchmarkStoargeSequentialWrite(b *testing.B) {
+//	var (
+//		st, _, _, e, src = setupBenchmarkStorage(b)
+//		err              error
+//	)
+//	b.Run("BenchmarkStoargeSequentialWrite", func(b *testing.B) {
+//		deleteBenchmarkData(b, st)
+//		b.ResetTimer()
+//		for i := 0; i < b.N; i++ {
+//			if _, err = st.Writer().Exec(e, src[ipkg.next()]...); err != nil {
+//				b.Errorf("Failed to execute: %v", err)
+//			}
+//		}
+//	})
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+//func BenchmarkStoargeSequentialWriteTx(b *testing.B) {
+//	var (
+//		st, _, _, e, src = setupBenchmarkStorage(b)
+//		tx               *sql.Tx
+//		err              error
+//	)
+//	for i := 0; i < b.N; i++ {
+//		if i%benchmarkQueriesPerTx == 0 {
+//			if tx, err = st.Writer().Begin(); err != nil {
+//				b.Errorf("Failed to begin transaction: %v", err)
+//			}
+//		}
+//		if _, err = tx.Exec(e, src[ipkg.next()]...); err != nil {
+//			b.Errorf("Failed to execute: %v", err)
+//		}
+//		if (i+1)%benchmarkQueriesPerTx == 0 || i == b.N-1 {
+//			if err = tx.Commit(); err != nil {
+//				b.Errorf("Failed to commit transaction: %v", err)
+//			}
+//		}
+//	}
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+// BW is a background writer function passed to benchmark helper.
+//type BW func(
+//	*testing.B, *sync.WaitGroup, <-chan struct{}, xi.Storage, keygen, string, [][]interface{},
+//)
+
+func busyWrite(
+	b *testing.B,
+	wg *sync.WaitGroup, sc <-chan struct{},
+	st xi.Storage, kg keygen, e string, src [][]interface{},
+) {
+	defer wg.Done()
+	var err error
+	for {
+		select {
+		case <-sc:
+			return
+		default:
+			if _, err = st.Writer().Exec(e, src[kg.next()]...); err != nil {
+				b.Errorf("Failed to execute: %v", err)
+			}
+		}
+	}
+}
+
+func busyWriteTx(
+	b *testing.B,
+	wg *sync.WaitGroup, sc <-chan struct{},
+	st xi.Storage, kg keygen, e string, src [][]interface{},
+) {
+	defer wg.Done()
+	var (
+		tx  *sql.Tx
+		err error
+	)
+	for i := 0; ; i++ {
+		// Begin
+		if i%benchmarkQueriesPerTx == 0 {
+			if tx, err = st.Writer().Begin(); err != nil {
+				b.Errorf("Failed to begin transaction: %v", err)
+			}
+		}
+		// Exec
+		select {
+		case <-sc:
+			// Also commit on exiting
+			if tx != nil {
+				if err = tx.Commit(); err != nil {
+					b.Errorf("Failed to commit transaction: %v", err)
+				}
+				tx = nil
+			}
+			return
+		default:
+			// Exec
+			if _, err = tx.Exec(e, src[kg.next()]...); err != nil {
+				b.Errorf("Failed to execute: %v", err)
+			}
+		}
+		// Commit
+		if (i+1)%benchmarkQueriesPerTx == 0 {
+			if err = tx.Commit(); err != nil {
+				b.Errorf("Failed to commit transaction: %v", err)
+			}
+			tx = nil
+		}
+	}
+}
+
+func idleWriteTx(
+	b *testing.B,
+	wg *sync.WaitGroup, sc <-chan struct{},
+	st xi.Storage, kg keygen, e string, src [][]interface{},
+) {
+	const writeIntlMS = 1
+	var (
+		tx     *sql.Tx
+		err    error
+		ticker = time.NewTicker(writeIntlMS * time.Millisecond)
+	)
+	defer func() {
+		ticker.Stop()
+		wg.Done()
+	}()
+	for i := 0; ; i++ {
+		// Begin
+		if i%benchmarkQueriesPerTx == 0 {
+			if tx, err = st.Writer().Begin(); err != nil {
+				b.Errorf("Failed to begin transaction: %v", err)
+			}
+		}
+		// Exec
+		select {
+		case <-ticker.C:
+			// Exec
+			if _, err = tx.Exec(e, src[kg.next()]...); err != nil {
+				b.Errorf("Failed to execute: %v", err)
+			}
+		case <-sc:
+			// Also commit on exiting
+			if tx != nil {
+				if err = tx.Commit(); err != nil {
+					b.Errorf("Failed to commit transaction: %v", err)
+				}
+				tx = nil
+			}
+			return
+		}
+		// Commit
+		if (i+1)%benchmarkQueriesPerTx == 0 {
+			if err = tx.Commit(); err != nil {
+				b.Errorf("Failed to commit transaction: %v", err)
+			}
+			tx = nil
+		}
+	}
+}
+
+// GR is a get reader function passed to benchmark helper.
+//type GR func(xi.Storage) *sql.DB
+//
+//func getDirtyReader(st xi.Storage) *sql.DB { return st.DirtyReader() }
+//func getReader(st xi.Storage) *sql.DB      { return st.Reader() }
+//
+//func benchmarkStorageSequentialReadWithBackgroundWriter(b *testing.B, getReader GR, write BW) {
+//	var (
+//		st, q, dm, e, src = setupBenchmarkStorage(b)
+//
+//		dest = dm()
+//		wg   = &sync.WaitGroup{}
+//		sc   = make(chan struct{})
+//
+//		err error
+//	)
+//
+//	// Start background writer
+//	wg.Add(1)
+//	go write(b, wg, sc, st, ipkg, e, src)
+//
+//	for i := 0; i < b.N; i++ {
+//		if err = getReader(st).QueryRow(
+//			q, trkg.next(),
+//		).Scan(dest...); err != nil && err != sql.ErrNoRows {
+//			b.Fatalf("Failed to query values: %v", err)
+//		}
+//	}
+//
+//	// Exit background writer
+//	close(sc)
+//	wg.Wait()
+//
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+//func BenchmarkStoargeSequentialDirtyReadWithBackgroundWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadWithBackgroundWriter(b, getDirtyReader, busyWrite)
+//}
+//
+//func BenchmarkStoargeSequentialReadWithBackgroundWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadWithBackgroundWriter(b, getReader, busyWrite)
+//}
+//
+//func BenchmarkStoargeSequentialDirtyReadWithBackgroundBusyTxWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadWithBackgroundWriter(b, getDirtyReader, busyWriteTx)
+//}
+//
+//func BenchmarkStoargeSequentialReadWithBackgroundBusyTxWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadWithBackgroundWriter(b, getReader, busyWriteTx)
+//}
+//
+//func BenchmarkStoargeSequentialDirtyReadWithBackgroundIdleTxWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadWithBackgroundWriter(b, getDirtyReader, idleWriteTx)
+//}
+//
+//func BenchmarkStoargeSequentialReadWithBackgroundIdleTxWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadWithBackgroundWriter(b, getReader, idleWriteTx)
+//}
+//
+//func benchmarkStorageSequentialReadTxWithBackgroundWriter(b *testing.B, getReader GR, write BW) {
+//	var (
+//		st, q, dm, e, src = setupBenchmarkStorage(b)
+//
+//		dest = dm()
+//		wg   = &sync.WaitGroup{}
+//		sc   = make(chan struct{})
+//
+//		err error
+//		tx  *sql.Tx
+//	)
+//
+//	// Start background writer
+//	wg.Add(1)
+//	go write(b, wg, sc, st, ipkg, e, src)
+//
+//	for i := 0; i < b.N; i++ {
+//		if i%benchmarkQueriesPerTx == 0 {
+//			if tx, err = getReader(st).Begin(); err != nil {
+//				b.Fatalf("Failed to begin transaction: %v", err)
+//			}
+//		}
+//		// Query in [n, 2n-1] key space
+//		if err = tx.QueryRow(q, nrkg.next()).Scan(dest...); err != nil && err != sql.ErrNoRows {
+//			b.Fatalf("Failed to query values: %v", err)
+//		}
+//		if (i+1)%benchmarkQueriesPerTx == 0 || i == b.N-1 {
+//			if err = tx.Rollback(); err != nil {
+//				b.Fatalf("Failed to close transaction: %v", err)
+//			}
+//		}
+//	}
+//
+//	// Exit background writer
+//	close(sc)
+//	wg.Wait()
+//
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+//func BenchmarkStoargeSequentialDirtyReadTxWithBackgroundWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadTxWithBackgroundWriter(b, getDirtyReader, busyWrite)
+//}
+//
+//func BenchmarkStoargeSequentialReadTxWithBackgroundWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadTxWithBackgroundWriter(b, getReader, busyWrite)
+//}
+//
+//func BenchmarkStoargeSequentialDirtyReadTxWithBackgroundBusyTxWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadTxWithBackgroundWriter(b, getDirtyReader, busyWriteTx)
+//}
+//
+//func BenchmarkStoargeSequentialReadTxWithBackgroundBusyTxWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadTxWithBackgroundWriter(b, getReader, busyWriteTx)
+//}
+//
+//func BenchmarkStoargeSequentialDirtyReadTxWithBackgroundIdleTxWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadTxWithBackgroundWriter(b, getDirtyReader, idleWriteTx)
+//}
+//
+//func BenchmarkStoargeSequentialReadTxWithBackgroundIdleTxWriter(b *testing.B) {
+//	benchmarkStorageSequentialReadTxWithBackgroundWriter(b, getReader, idleWriteTx)
+//}
+//
+//func BenchmarkStoargeSequentialMixDRW(b *testing.B) {
+//	var (
+//		st, q, dm, e, src = setupBenchmarkStorage(b)
+//		dest              = dm()
+//		err               error
+//	)
+//	for i := 0; i < b.N; i++ {
+//		if rand.Int()%2 == 0 {
+//			if err = st.DirtyReader().QueryRow(q, rrkg.next()).Scan(dest...); err != nil {
+//				b.Fatalf("Failed to query values: %v", err)
+//			}
+//		} else {
+//			if _, err = st.Writer().Exec(e, src[ipkg.next()]...); err != nil {
+//				b.Fatalf("Failed to execute: %v", err)
+//			}
+//		}
+//	}
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+//func BenchmarkStoargeSequentialMixRW(b *testing.B) {
+//	var (
+//		st, q, dm, e, src = setupBenchmarkStorage(b)
+//		dest              = dm()
+//		err               error
+//	)
+//	for i := 0; i < b.N; i++ {
+//		if rand.Int()%2 == 0 {
+//			if err = st.Reader().QueryRow(q, rrkg.next()).Scan(dest...); err != nil {
+//				b.Fatalf("Failed to query values: %v", err)
+//			}
+//		} else {
+//			if _, err = st.Writer().Exec(e, src[ipkg.next()]...); err != nil {
+//				b.Fatalf("Failed to execute: %v", err)
+//			}
+//		}
+//	}
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+//func BenchmarkStorageParallelDirtyRead(b *testing.B) {
+//	var (
+//		st, q, dm, _, _ = setupBenchmarkStorage(b)
+//	)
+//	b.RunParallel(func(pb *testing.PB) {
+//		var (
+//			dest = dm()
+//			err  error
+//		)
+//		for pb.Next() {
+//			if err = st.DirtyReader().QueryRow(q, rrkg.next()).Scan(dest...); err != nil {
+//				b.Fatalf("Failed to query values: %v", err)
+//			}
+//		}
+//	})
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+//func BenchmarkStorageParallelRead(b *testing.B) {
+//	var (
+//		st, q, dm, _, _ = setupBenchmarkStorage(b)
+//	)
+//	b.RunParallel(func(pb *testing.PB) {
+//		var (
+//			dest = dm()
+//			err  error
+//		)
+//		for pb.Next() {
+//			if err = st.DirtyReader().QueryRow(q, rrkg.next()).Scan(dest...); err != nil {
+//				b.Fatalf("Failed to query values: %v", err)
+//			}
+//		}
+//	})
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+//func BenchmarkStoargeParallelWrite(b *testing.B) {
+//	var st, _, _, e, src = setupBenchmarkStorage(b)
+//	b.RunParallel(func(pb *testing.PB) {
+//		var err error
+//		for pb.Next() {
+//			if _, err = st.Writer().Exec(e, src[ipkg.next()]...); err != nil {
+//				b.Fatalf("Failed to execute: %v", err)
+//			}
+//		}
+//	})
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+//func BenchmarkStorageParallelMixDRW(b *testing.B) {
+//	var st, q, dm, e, src = setupBenchmarkStorage(b)
+//	b.RunParallel(func(pb *testing.PB) {
+//		var (
+//			dest = dm()
+//			err  error
+//		)
+//		for pb.Next() {
+//			if rand.Int()%2 == 0 {
+//				if err = st.DirtyReader().QueryRow(q, rrkg.next()).Scan(dest...); err != nil {
+//					b.Fatalf("Failed to query values: %v", err)
+//				}
+//			} else {
+//				if _, err = st.Writer().Exec(e, src[ipkg.next()]...); err != nil {
+//					b.Fatalf("Failed to execute: %v", err)
+//				}
+//			}
+//		}
+//	})
+//	teardownBenchmarkStorage(b, st)
+//}
+//
+//func BenchmarkStorageParallelMixRW(b *testing.B) {
+//	var st, q, dm, e, src = setupBenchmarkStorage(b)
+//	b.RunParallel(func(pb *testing.PB) {
+//		var (
+//			dest = dm()
+//			err  error
+//		)
+//		for pb.Next() {
+//			if rand.Int()%2 == 0 {
+//				if err = st.Reader().QueryRow(q, rrkg.next()).Scan(dest...); err != nil {
+//					b.Fatalf("Failed to query values: %v", err)
+//				}
+//			} else {
+//				if _, err = st.Writer().Exec(e, src[ipkg.next()]...); err != nil {
+//					b.Fatalf("Failed to execute: %v", err)
+//				}
+//			}
+//		}
+//	})
+//	teardownBenchmarkStorage(b, st)
+//}
diff --git a/xenomint/sqlite/xxx_test.go b/xenomint/sqlite/xxx_test.go
new file mode 100644
index 000000000..3c211b975
--- /dev/null
+++ b/xenomint/sqlite/xxx_test.go
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sqlite
+
+import (
+	"io/ioutil"
+	"math/rand"
+	"os"
+	"syscall"
+	"testing"
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
+)
+
+var (
+	testingDataDir string
+)
+
+func setup() {
+	const minNoFile uint64 = 4096
+	var (
+		err error
+		lmt syscall.Rlimit
+	)
+
+	if testingDataDir, err = ioutil.TempDir("", "CovenantSQL"); err != nil {
+		panic(err)
+	}
+
+	rand.Seed(time.Now().UnixNano())
+
+	if err = syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lmt); err != nil {
+		panic(err)
+	}
+	if lmt.Max < minNoFile {
+		panic("insufficient max RLIMIT_NOFILE")
+	}
+	lmt.Cur = lmt.Max
+	if err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &lmt); err != nil {
+		panic(err)
+	}
+
+	log.SetOutput(os.Stdout)
+	log.SetLevel(log.DebugLevel)
+}
+
+func teardown() {
+	if err := os.RemoveAll(testingDataDir); err != nil {
+		panic(err)
+	}
+}
+
+func TestMain(m *testing.M) {
+	os.Exit(func() int {
+		setup()
+		defer teardown()
+		return m.Run()
+	}())
+}
diff --git a/xenomint/state.go b/xenomint/state.go
new file mode 100644
index 000000000..8599cf012
--- /dev/null
+++ b/xenomint/state.go
@@ -0,0 +1,635 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xenomint
+
+import (
+	"database/sql"
+	"io"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/types"
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
+	xi "github.com/CovenantSQL/CovenantSQL/xenomint/interfaces"
+	"github.com/CovenantSQL/sqlparser"
+	"github.com/pkg/errors"
+)
+
+// State defines a xenomint state which is bound to a underlying storage.
+type State struct {
+	sync.RWMutex
+	strg   xi.Storage
+	pool   *pool
+	closed bool
+	nodeID proto.NodeID
+
+	// TODO(leventeliu): Reload savepoint from last block on chain initialization, and rollback
+	// any ongoing transaction on exit.
+	//
+	// unc is the uncommitted transaction.
+	unc             *sql.Tx
+	origin          uint64 // origin is the original savepoint of the current transaction
+	cmpoint         uint64 // cmpoint is the last commit point of the current transaction
+	current         uint64 // current is the current savepoint of the current transaction
+	hasSchemaChange uint32 // indicates schema change happens in this uncommitted transaction
+}
+
+// NewState returns a new State bound to strg.
+func NewState(nodeID proto.NodeID, strg xi.Storage) (s *State, err error) {
+	var t = &State{
+		nodeID: nodeID,
+		strg:   strg,
+		pool:   newPool(),
+	}
+	if t.unc, err = t.strg.Writer().Begin(); err != nil {
+		return
+	}
+	t.setSavepoint()
+	s = t
+	return
+}
+
+func (s *State) incSeq() {
+	s.current++
+}
+
+func (s *State) setNextTxID() {
+	s.origin = s.current
+	s.cmpoint = s.current
+}
+
+func (s *State) setCommitPoint() {
+	s.cmpoint = s.current
+}
+
+func (s *State) rollbackID(id uint64) {
+	s.current = id
+}
+
+// InitTx sets the initial id of the current transaction. This method is not safe for concurrency
+// and should only be called at initialization.
+func (s *State) InitTx(id uint64) {
+	s.origin = id
+	s.cmpoint = id
+	s.current = id
+	s.setSavepoint()
+}
+
+func (s *State) getID() uint64 {
+	return atomic.LoadUint64(&s.current)
+}
+
+// Close commits any ongoing transaction if needed and closes the underlying storage.
+func (s *State) Close(commit bool) (err error) {
+	if s.closed {
+		return
+	}
+	if s.unc != nil {
+		if commit {
+			if err = s.uncCommit(); err != nil {
+				return
+			}
+		} else {
+			// Only rollback to last commmit point
+			if err = s.rollback(); err != nil {
+				return
+			}
+			if err = s.uncCommit(); err != nil {
+				return
+			}
+		}
+	}
+	if err = s.strg.Close(); err != nil {
+		return
+	}
+	s.closed = true
+	return
+}
+
+func convertQueryAndBuildArgs(pattern string, args []types.NamedArg) (containsDDL bool, p string, ifs []interface{}, err error) {
+	var (
+		tokenizer  = sqlparser.NewStringTokenizer(pattern)
+		stmt       sqlparser.Statement
+		lastPos    int
+		query      string
+		queryParts []string
+	)
+
+	for {
+		stmt, err = sqlparser.ParseNext(tokenizer)
+
+		if err != nil && err != io.EOF {
+			return
+		}
+
+		if err == io.EOF {
+			err = nil
+			break
+		}
+
+		query = pattern[lastPos : tokenizer.Position-1]
+		lastPos = tokenizer.Position + 1
+
+		// translate show statement
+		if showStmt, ok := stmt.(*sqlparser.Show); ok {
+			origQuery := query
+
+			switch showStmt.Type {
+			case "table":
+				if showStmt.ShowCreate {
+					query = "SELECT sql FROM sqlite_master WHERE type = \"table\" AND tbl_name = \"" +
+						showStmt.OnTable.Name.String() + "\""
+				} else {
+					query = "PRAGMA table_info(" + showStmt.OnTable.Name.String() + ")"
+				}
+			case "index":
+				query = "SELECT name FROM sqlite_master WHERE type = \"index\" AND tbl_name = \"" +
+					showStmt.OnTable.Name.String() + "\""
+			case "tables":
+				query = "SELECT name FROM sqlite_master WHERE type = \"table\""
+			}
+
+			log.WithFields(log.Fields{
+				"from": origQuery,
+				"to":   query,
+			}).Debug("query translated")
+		} else if _, ok := stmt.(*sqlparser.DDL); ok {
+			containsDDL = true
+		}
+
+		queryParts = append(queryParts, query)
+	}
+
+	p = strings.Join(queryParts, "; ")
+
+	ifs = make([]interface{}, len(args))
+	for i, v := range args {
+		ifs[i] = sql.NamedArg{
+			Name:  v.Name,
+			Value: v.Value,
+		}
+	}
+	return
+}
+
+func buildTypeNamesFromSQLColumnTypes(types []*sql.ColumnType) (names []string) {
+	names = make([]string, len(types))
+	for i, v := range types {
+		names[i] = v.DatabaseTypeName()
+	}
+	return
+}
+
+type sqlQuerier interface {
+	Query(query string, args ...interface{}) (*sql.Rows, error)
+}
+
+func readSingle(
+	qer sqlQuerier, q *types.Query) (names []string, types []string, data [][]interface{}, err error,
+) {
+	var (
+		rows    *sql.Rows
+		cols    []*sql.ColumnType
+		pattern string
+		args    []interface{}
+	)
+
+	if _, pattern, args, err = convertQueryAndBuildArgs(q.Pattern, q.Args); err != nil {
+		return
+	}
+	if rows, err = qer.Query(pattern, args...); err != nil {
+		return
+	}
+	defer rows.Close()
+	// Fetch column names and types
+	if names, err = rows.Columns(); err != nil {
+		return
+	}
+	if cols, err = rows.ColumnTypes(); err != nil {
+		return
+	}
+	types = buildTypeNamesFromSQLColumnTypes(cols)
+	// Scan data row by row
+	data = make([][]interface{}, 0)
+	for rows.Next() {
+		var (
+			row  = make([]interface{}, len(cols))
+			dest = make([]interface{}, len(cols))
+		)
+		for i := range row {
+			dest[i] = &row[i]
+		}
+		if err = rows.Scan(dest...); err != nil {
+			return
+		}
+		data = append(data, row)
+	}
+	return
+}
+
+func buildRowsFromNativeData(data [][]interface{}) (rows []types.ResponseRow) {
+	rows = make([]types.ResponseRow, len(data))
+	for i, v := range data {
+		rows[i].Values = v
+	}
+	return
+}
+
+func (s *State) read(req *types.Request) (ref *QueryTracker, resp *types.Response, err error) {
+	var (
+		ierr           error
+		cnames, ctypes []string
+		data           [][]interface{}
+	)
+	// TODO(leventeliu): no need to run every read query here.
+	for i, v := range req.Payload.Queries {
+		if cnames, ctypes, data, ierr = readSingle(s.strg.DirtyReader(), &v); ierr != nil {
+			err = errors.Wrapf(ierr, "query at #%d failed", i)
+			// Add to failed pool list
+			s.pool.setFailed(req)
+			return
+		}
+	}
+	// Build query response
+	ref = &QueryTracker{Req: req}
+	resp = &types.Response{
+		Header: types.SignedResponseHeader{
+			ResponseHeader: types.ResponseHeader{
+				Request:   req.Header,
+				NodeID:    s.nodeID,
+				Timestamp: s.getLocalTime(),
+				RowCount:  uint64(len(data)),
+				LogOffset: s.getID(),
+			},
+		},
+		Payload: types.ResponsePayload{
+			Columns:   cnames,
+			DeclTypes: ctypes,
+			Rows:      buildRowsFromNativeData(data),
+		},
+	}
+	return
+}
+
+func (s *State) readTx(req *types.Request) (ref *QueryTracker, resp *types.Response, err error) {
+	var (
+		tx             *sql.Tx
+		id             uint64
+		ierr           error
+		cnames, ctypes []string
+		data           [][]interface{}
+		querier        sqlQuerier
+	)
+	id = s.getID()
+	if atomic.LoadUint32(&s.hasSchemaChange) == 1 {
+		// lock transaction
+		s.Lock()
+		defer s.Unlock()
+		s.setSavepoint()
+		querier = s.unc
+		defer s.rollbackTo(id)
+	} else {
+		if tx, ierr = s.strg.DirtyReader().Begin(); ierr != nil {
+			err = errors.Wrap(ierr, "open tx failed")
+			return
+		}
+		querier = tx
+		defer tx.Rollback()
+	}
+
+	for i, v := range req.Payload.Queries {
+		if cnames, ctypes, data, ierr = readSingle(querier, &v); ierr != nil {
+			err = errors.Wrapf(ierr, "query at #%d failed", i)
+			// Add to failed pool list
+			s.pool.setFailed(req)
+			return
+		}
+	}
+	// Build query response
+	ref = &QueryTracker{Req: req}
+	resp = &types.Response{
+		Header: types.SignedResponseHeader{
+			ResponseHeader: types.ResponseHeader{
+				Request:   req.Header,
+				NodeID:    s.nodeID,
+				Timestamp: s.getLocalTime(),
+				RowCount:  uint64(len(data)),
+				LogOffset: id,
+			},
+		},
+		Payload: types.ResponsePayload{
+			Columns:   cnames,
+			DeclTypes: ctypes,
+			Rows:      buildRowsFromNativeData(data),
+		},
+	}
+	return
+}
+
+func (s *State) writeSingle(q *types.Query) (res sql.Result, err error) {
+	var (
+		containsDDL bool
+		pattern     string
+		args        []interface{}
+	)
+
+	if containsDDL, pattern, args, err = convertQueryAndBuildArgs(q.Pattern, q.Args); err != nil {
+		return
+	}
+	if res, err = s.unc.Exec(pattern, args...); err == nil {
+		if containsDDL {
+			atomic.StoreUint32(&s.hasSchemaChange, 1)
+		}
+		s.incSeq()
+	}
+	return
+}
+
+func (s *State) setSavepoint() (savepoint uint64) {
+	savepoint = s.getID()
+	s.unc.Exec("SAVEPOINT \"?\"", savepoint)
+	return
+}
+
+func (s *State) rollbackTo(savepoint uint64) {
+	s.rollbackID(savepoint)
+	s.unc.Exec("ROLLBACK TO \"?\"", savepoint)
+}
+
+func (s *State) write(req *types.Request) (ref *QueryTracker, resp *types.Response, err error) {
+	var (
+		savepoint         uint64
+		query             = &QueryTracker{Req: req}
+		totalAffectedRows int64
+		curAffectedRows   int64
+		lastInsertID      int64
+	)
+
+	// TODO(leventeliu): savepoint is a sqlite-specified solution for nested transaction.
+	if err = func() (err error) {
+		var ierr error
+		s.Lock()
+		defer s.Unlock()
+		savepoint = s.getID()
+		for i, v := range req.Payload.Queries {
+			var res sql.Result
+			if res, ierr = s.writeSingle(&v); ierr != nil {
+				err = errors.Wrapf(ierr, "execute at #%d failed", i)
+				// Add to failed pool list
+				s.pool.setFailed(req)
+				s.rollbackTo(savepoint)
+				return
+			}
+
+			curAffectedRows, _ = res.RowsAffected()
+			lastInsertID, _ = res.LastInsertId()
+			totalAffectedRows += curAffectedRows
+		}
+		s.setSavepoint()
+		s.pool.enqueue(savepoint, query)
+		return
+	}(); err != nil {
+		return
+	}
+	// Build query response
+	ref = query
+	resp = &types.Response{
+		Header: types.SignedResponseHeader{
+			ResponseHeader: types.ResponseHeader{
+				Request:      req.Header,
+				NodeID:       s.nodeID,
+				Timestamp:    s.getLocalTime(),
+				RowCount:     0,
+				LogOffset:    savepoint,
+				AffectedRows: totalAffectedRows,
+				LastInsertID: lastInsertID,
+			},
+		},
+	}
+	return
+}
+
+func (s *State) replay(req *types.Request, resp *types.Response) (err error) {
+	var (
+		ierr      error
+		savepoint uint64
+		query     = &QueryTracker{Req: req, Resp: resp}
+	)
+	s.Lock()
+	defer s.Unlock()
+	savepoint = s.getID()
+	if resp.Header.ResponseHeader.LogOffset != savepoint {
+		err = errors.Wrapf(
+			ErrQueryConflict,
+			"local id %d vs replaying id %d", savepoint, resp.Header.ResponseHeader.LogOffset,
+		)
+		return
+	}
+	for i, v := range req.Payload.Queries {
+		if _, ierr = s.writeSingle(&v); ierr != nil {
+			err = errors.Wrapf(ierr, "execute at #%d failed", i)
+			s.rollbackTo(savepoint)
+			return
+		}
+	}
+	s.setSavepoint()
+	s.pool.enqueue(savepoint, query)
+	return
+}
+
+// ReplayBlock replays the queries from block. It also checks and skips some preceding pooled
+// queries.
+func (s *State) ReplayBlock(block *types.Block) (err error) {
+	var (
+		ierr   error
+		lastsp uint64 // Last savepoint
+	)
+	s.Lock()
+	defer s.Unlock()
+	for i, q := range block.QueryTxs {
+		var query = &QueryTracker{Req: q.Request, Resp: &types.Response{Header: *q.Response}}
+		lastsp = s.getID()
+		if q.Response.ResponseHeader.LogOffset > lastsp {
+			err = ErrMissingParent
+			return
+		}
+		// Match and skip already pooled query
+		if q.Response.ResponseHeader.LogOffset < lastsp {
+			if !s.pool.match(q.Response.ResponseHeader.LogOffset, q.Request) {
+				err = ErrQueryConflict
+				return
+			}
+			continue
+		}
+		// Replay query
+		for j, v := range q.Request.Payload.Queries {
+			if q.Request.Header.QueryType == types.ReadQuery {
+				continue
+			}
+			if q.Request.Header.QueryType != types.WriteQuery {
+				err = errors.Wrapf(ErrInvalidRequest, "replay block at %d:%d", i, j)
+				s.rollbackTo(lastsp)
+				return
+			}
+			if _, ierr = s.writeSingle(&v); ierr != nil {
+				err = errors.Wrapf(ierr, "execute at %d:%d failed", i, j)
+				s.rollbackTo(lastsp)
+				return
+			}
+		}
+		s.setSavepoint()
+		s.pool.enqueue(lastsp, query)
+	}
+	// Remove duplicate failed queries from local pool
+	for _, r := range block.FailedReqs {
+		s.pool.removeFailed(r)
+	}
+	// Check if the current transaction is ok to commit
+	if s.pool.matchLast(lastsp) {
+		if err = s.uncCommit(); err != nil {
+			// FATAL ERROR
+			return
+		}
+		if s.unc, err = s.strg.Writer().Begin(); err != nil {
+			// FATAL ERROR
+			return
+		}
+		s.setNextTxID()
+	} else {
+		// Set commit point only, transaction is not actually committed. This commit point will be
+		// used on exiting.
+		s.setCommitPoint()
+	}
+	s.setSavepoint()
+	// Truncate pooled queries
+	s.pool.truncate(lastsp)
+	return
+}
+
+func (s *State) commit() (err error) {
+	s.Lock()
+	defer s.Unlock()
+	if err = s.uncCommit(); err != nil {
+		return
+	}
+	if s.unc, err = s.strg.Writer().Begin(); err != nil {
+		return
+	}
+	s.setNextTxID()
+	s.setSavepoint()
+	_ = s.pool.queries
+	s.pool = newPool()
+	return
+}
+
+// CommitEx commits the current transaction and returns all the pooled queries.
+func (s *State) CommitEx() (failed []*types.Request, queries []*QueryTracker, err error) {
+	s.Lock()
+	defer s.Unlock()
+	if err = s.uncCommit(); err != nil {
+		// FATAL ERROR
+		return
+	}
+	if s.unc, err = s.strg.Writer().Begin(); err != nil {
+		// FATAL ERROR
+		return
+	}
+	s.setNextTxID()
+	s.setSavepoint()
+	// Return pooled items and reset
+	failed = s.pool.failedList()
+	queries = s.pool.queries
+	s.pool = newPool()
+	return
+}
+
+func (s *State) uncCommit() (err error) {
+	if err = s.unc.Commit(); err != nil {
+		return
+	}
+
+	// reset schema change flag
+	atomic.StoreUint32(&s.hasSchemaChange, 0)
+
+	return
+}
+
+func (s *State) rollback() (err error) {
+	s.Lock()
+	defer s.Unlock()
+	s.rollbackTo(s.cmpoint)
+	s.current = s.cmpoint
+	return
+}
+
+func (s *State) getLocalTime() time.Time {
+	return time.Now().UTC()
+}
+
+// Query does the query(ies) in req, pools the request and persists any change to
+// the underlying storage.
+func (s *State) Query(req *types.Request) (ref *QueryTracker, resp *types.Response, err error) {
+	switch req.Header.QueryType {
+	case types.ReadQuery:
+		return s.readTx(req)
+	case types.WriteQuery:
+		return s.write(req)
+	default:
+		err = ErrInvalidRequest
+	}
+	return
+}
+
+// Replay replays a write log from other peer to replicate storage state.
+func (s *State) Replay(req *types.Request, resp *types.Response) (err error) {
+	// NOTE(leventeliu): in the current implementation, failed requests are not tracked in remote
+	// nodes (while replaying via Replay calls). Because we don't want to actually replay read
+	// queries in all synchronized nodes, meanwhile, whether a request will fail or not
+	// remains unknown until we actually replay it -- a dead end here.
+	// So we just keep failed requests in local pool and report them in the next local block
+	// producing.
+	switch req.Header.QueryType {
+	case types.ReadQuery:
+		return
+	case types.WriteQuery:
+		return s.replay(req, resp)
+	default:
+		err = ErrInvalidRequest
+	}
+	return
+}
+
+// Stat prints the statistic message of the State object.
+func (s *State) Stat(id proto.DatabaseID) {
+	var (
+		p = func() *pool {
+			s.RLock()
+			defer s.RUnlock()
+			return s.pool
+		}()
+		fc = atomic.LoadInt32(&p.failedRequestCount)
+		tc = atomic.LoadInt32(&p.trackerCount)
+	)
+	log.WithFields(log.Fields{
+		"database_id":               id,
+		"pooled_fail_request_count": fc,
+		"pooled_query_tracker":      tc,
+	}).Info("Xeno pool stats")
+}
diff --git a/xenomint/state_test.go b/xenomint/state_test.go
new file mode 100644
index 000000000..783142a15
--- /dev/null
+++ b/xenomint/state_test.go
@@ -0,0 +1,521 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xenomint
+
+import (
+	"database/sql"
+	"fmt"
+	"os"
+	"path"
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/types"
+	xi "github.com/CovenantSQL/CovenantSQL/xenomint/interfaces"
+	xs "github.com/CovenantSQL/CovenantSQL/xenomint/sqlite"
+	"github.com/pkg/errors"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestState(t *testing.T) {
+	Convey("Given a chain state object", t, func() {
+		var (
+			id1          = proto.DatabaseID("db-x1")
+			fl1          = path.Join(testingDataDir, fmt.Sprint(t.Name(), "x1"))
+			fl2          = path.Join(testingDataDir, fmt.Sprint(t.Name(), "x2"))
+			st1, st2     *State
+			strg1, strg2 xi.Storage
+			err          error
+		)
+		nodeID := proto.NodeID("0000000000000000000000000000000000000000000000000000000000000000")
+		strg1, err = xs.NewSqlite(fmt.Sprint("file:", fl1))
+		So(err, ShouldBeNil)
+		So(strg1, ShouldNotBeNil)
+		st1, err = NewState(nodeID, strg1)
+		So(err, ShouldBeNil)
+		So(st1, ShouldNotBeNil)
+		Reset(func() {
+			// Clean database file after each pass
+			err = st1.Close(true)
+			So(err, ShouldBeNil)
+			err = os.Remove(fl1)
+			So(err, ShouldBeNil)
+			err = os.Remove(fmt.Sprint(fl1, "-shm"))
+			So(err == nil || os.IsNotExist(err), ShouldBeTrue)
+			err = os.Remove(fmt.Sprint(fl1, "-wal"))
+			So(err == nil || os.IsNotExist(err), ShouldBeTrue)
+		})
+		strg2, err = xs.NewSqlite(fmt.Sprint("file:", fl2))
+		So(err, ShouldBeNil)
+		So(strg1, ShouldNotBeNil)
+		st2, err = NewState(nodeID, strg2)
+		So(err, ShouldBeNil)
+		So(st1, ShouldNotBeNil)
+		Reset(func() {
+			// Clean database file after each pass
+			err = st2.Close(true)
+			So(err, ShouldBeNil)
+			err = os.Remove(fl2)
+			So(err, ShouldBeNil)
+			err = os.Remove(fmt.Sprint(fl2, "-shm"))
+			So(err == nil || os.IsNotExist(err), ShouldBeTrue)
+			err = os.Remove(fmt.Sprint(fl2, "-wal"))
+			So(err == nil || os.IsNotExist(err), ShouldBeTrue)
+		})
+		Convey("When storage is closed", func() {
+			err = st1.Close(false)
+			So(err, ShouldBeNil)
+			Convey("The storage should report error for any incoming query", func() {
+				var req = buildRequest(types.WriteQuery, []types.Query{
+					buildQuery(`CREATE TABLE t1 (k INT, v TEXT, PRIMARY KEY(k))`),
+				})
+				_, _, err = st1.Query(req)
+				So(err, ShouldNotBeNil)
+				err = errors.Cause(err)
+				So(err, ShouldNotBeNil)
+				So(err, ShouldEqual, sql.ErrTxDone)
+			})
+		})
+		Convey("The state will report error on read with uncommitted schema change", func() {
+			var (
+				req = buildRequest(types.WriteQuery, []types.Query{
+					buildQuery(`CREATE TABLE t1 (k INT, v TEXT, PRIMARY KEY(k))`),
+				})
+				resp *types.Response
+			)
+			_, resp, err = st1.Query(req)
+			So(err, ShouldBeNil)
+			So(resp, ShouldNotBeNil)
+			_, resp, err = st1.Query(buildRequest(types.ReadQuery, []types.Query{
+				buildQuery(`SELECT * FROM t1`),
+			}))
+			// any schema change query will trigger performance degradation mode in current block
+			So(err, ShouldBeNil)
+		})
+		Convey("When a basic KV table is created", func() {
+			var (
+				values = [][]interface{}{
+					{int64(1), []byte("v1")},
+					{int64(2), []byte("v2")},
+					{int64(3), []byte("v3")},
+					{int64(4), []byte("v4")},
+				}
+				req = buildRequest(types.WriteQuery, []types.Query{
+					buildQuery(`CREATE TABLE t1 (k INT, v TEXT, PRIMARY KEY(k))`),
+				})
+				resp *types.Response
+			)
+			_, resp, err = st1.Query(req)
+			So(err, ShouldBeNil)
+			So(resp, ShouldNotBeNil)
+			err = st1.commit()
+			So(err, ShouldBeNil)
+			_, resp, err = st2.Query(req)
+			So(err, ShouldBeNil)
+			So(resp, ShouldNotBeNil)
+			err = st2.commit()
+			Convey("The state should not change after attempted writing in read query", func() {
+				_, resp, err = st1.Query(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?)`, 1, "v1"),
+					buildQuery(`SELECT v FROM t1 WHERE k=?`, 1),
+				}))
+				// The use of Query instead of Exec won't produce an "attempt to write" error
+				// like Exec, but it should still keep it readonly -- which means writes will
+				// be ignored in this case.
+				So(err, ShouldBeNil)
+				So(resp.Header.RowCount, ShouldEqual, 0)
+			})
+			Convey("The state should report invalid request with unknown query type", func() {
+				req = buildRequest(types.QueryType(0xff), []types.Query{
+					buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?)`, values[0]...),
+				})
+				_, resp, err = st1.Query(req)
+				So(err, ShouldEqual, ErrInvalidRequest)
+				So(resp, ShouldBeNil)
+				err = st1.Replay(req, nil)
+				So(err, ShouldEqual, ErrInvalidRequest)
+			})
+			Convey("The state should report error on malformed queries", func() {
+				_, resp, err = st1.Query(buildRequest(types.WriteQuery, []types.Query{
+					buildQuery(`XXXXXX INTO t1 (k, v) VALUES (?, ?)`, values[0]...),
+				}))
+				So(err, ShouldNotBeNil)
+				So(resp, ShouldBeNil)
+				st1.Stat(id1)
+				err = st1.Replay(buildRequest(types.WriteQuery, []types.Query{
+					buildQuery(`XXXXXX INTO t1 (k, v) VALUES (?, ?)`, values[0]...),
+				}), &types.Response{
+					Header: types.SignedResponseHeader{
+						ResponseHeader: types.ResponseHeader{
+							LogOffset: st1.getID(),
+						},
+					},
+				})
+				So(err, ShouldNotBeNil)
+				_, resp, err = st1.Query(buildRequest(types.WriteQuery, []types.Query{
+					buildQuery(`INSERT INTO t2 (k, v) VALUES (?, ?)`, values[0]...),
+				}))
+				So(err, ShouldNotBeNil)
+				So(resp, ShouldBeNil)
+				st1.Stat(id1)
+				err = st1.Replay(buildRequest(types.WriteQuery, []types.Query{
+					buildQuery(`INSERT INTO t2 (k, v) VALUES (?, ?)`, values[0]...),
+				}), &types.Response{
+					Header: types.SignedResponseHeader{
+						ResponseHeader: types.ResponseHeader{
+							LogOffset: st1.getID(),
+						},
+					},
+				})
+				So(err, ShouldNotBeNil)
+				st1.Stat(id1)
+				_, resp, err = st1.Query(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`XXXXXX v FROM t1`),
+				}))
+				So(err, ShouldNotBeNil)
+				So(resp, ShouldBeNil)
+				st1.Stat(id1)
+				_, resp, err = st1.Query(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`SELECT v FROM t2`),
+				}))
+				So(err, ShouldNotBeNil)
+				So(resp, ShouldBeNil)
+				st1.Stat(id1)
+				_, resp, err = st1.read(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`SELECT v FROM t2`),
+				}))
+				So(err, ShouldNotBeNil)
+				So(resp, ShouldBeNil)
+				st1.Stat(id1)
+			})
+			Convey("The state should work properly with reading/writing queries", func() {
+				_, resp, err = st1.Query(buildRequest(types.WriteQuery, []types.Query{
+					buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?)`, values[0]...),
+				}))
+				So(err, ShouldBeNil)
+				So(resp.Header.RowCount, ShouldEqual, 0)
+				_, resp, err = st1.Query(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`SELECT v FROM t1 WHERE k=?`, values[0][0]),
+				}))
+				So(err, ShouldBeNil)
+				So(resp.Header.RowCount, ShouldEqual, 1)
+				So(resp.Payload, ShouldResemble, types.ResponsePayload{
+					Columns:   []string{"v"},
+					DeclTypes: []string{"TEXT"},
+					Rows:      []types.ResponseRow{{Values: values[0][1:]}},
+				})
+				st1.Stat(id1)
+
+				_, resp, err = st1.Query(buildRequest(types.WriteQuery, []types.Query{
+					buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?)`, values[1]...),
+					buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?);
+INSERT INTO t1 (k, v) VALUES (?, ?)`, concat(values[2:4])...),
+				}))
+				So(err, ShouldBeNil)
+				So(resp.Header.RowCount, ShouldEqual, 0)
+				_, resp, err = st1.Query(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`SELECT v FROM t1`),
+				}))
+				So(err, ShouldBeNil)
+				So(resp.Header.RowCount, ShouldEqual, 4)
+				So(resp.Payload, ShouldResemble, types.ResponsePayload{
+					Columns:   []string{"v"},
+					DeclTypes: []string{"TEXT"},
+					Rows: []types.ResponseRow{
+						{Values: values[0][1:]},
+						{Values: values[1][1:]},
+						{Values: values[2][1:]},
+						{Values: values[3][1:]},
+					},
+				})
+				st1.Stat(id1)
+
+				_, resp, err = st1.Query(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`SELECT * FROM t1`),
+				}))
+				So(err, ShouldBeNil)
+				So(resp.Payload, ShouldResemble, types.ResponsePayload{
+					Columns:   []string{"k", "v"},
+					DeclTypes: []string{"INT", "TEXT"},
+					Rows: []types.ResponseRow{
+						{Values: values[0][:]},
+						{Values: values[1][:]},
+						{Values: values[2][:]},
+						{Values: values[3][:]},
+					},
+				})
+				st1.Stat(id1)
+
+				// Test show statements
+				_, resp, err = st1.Query(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`SHOW TABLE t1`),
+				}))
+				So(err, ShouldBeNil)
+				So(resp, ShouldNotBeNil)
+				_, resp, err = st1.Query(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`SHOW CREATE TABLE t1`),
+				}))
+				So(err, ShouldBeNil)
+				So(resp, ShouldNotBeNil)
+				_, resp, err = st1.Query(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`SHOW INDEX FROM TABLE t1`),
+				}))
+				So(err, ShouldBeNil)
+				So(resp, ShouldNotBeNil)
+				_, resp, err = st1.Query(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`SHOW TABLES`),
+				}))
+				So(err, ShouldBeNil)
+				So(resp, ShouldNotBeNil)
+				st1.Stat(id1)
+
+				// Also test a non-transaction read implementation
+				_, resp, err = st1.read(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`SELECT * FROM t1`),
+				}))
+				So(err, ShouldBeNil)
+				So(resp.Payload, ShouldResemble, types.ResponsePayload{
+					Columns:   []string{"k", "v"},
+					DeclTypes: []string{"INT", "TEXT"},
+					Rows: []types.ResponseRow{
+						{Values: values[0][:]},
+						{Values: values[1][:]},
+						{Values: values[2][:]},
+						{Values: values[3][:]},
+					},
+				})
+				st1.Stat(id1)
+			})
+			Convey("The state should skip read query while replaying", func() {
+				err = st1.Replay(buildRequest(types.ReadQuery, []types.Query{
+					buildQuery(`SELECT * FROM t1`),
+				}), nil)
+				So(err, ShouldBeNil)
+			})
+			Convey("The state should report conflict state while replaying bad request", func() {
+				err = st1.Replay(buildRequest(types.WriteQuery, []types.Query{
+					buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?)`, values[0]...),
+				}), &types.Response{
+					Header: types.SignedResponseHeader{
+						ResponseHeader: types.ResponseHeader{
+							LogOffset: uint64(0xff),
+						},
+					},
+				})
+				err = errors.Cause(err)
+				So(err, ShouldEqual, ErrQueryConflict)
+			})
+			Convey("The state should be reproducible in another instance", func() {
+				var (
+					qt   *QueryTracker
+					reqs = []*types.Request{
+						buildRequest(types.WriteQuery, []types.Query{
+							buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?)`, values[0]...),
+						}),
+						buildRequest(types.WriteQuery, []types.Query{
+							buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?)`, values[1]...),
+							buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?);
+INSERT INTO t1 (k, v) VALUES (?, ?)`, concat(values[2:4])...),
+						}),
+						buildRequest(types.WriteQuery, []types.Query{
+							buildQuery(`DELETE FROM t1 WHERE k=?`, values[2][0]),
+						}),
+					}
+				)
+				for i := range reqs {
+					qt, resp, err = st1.Query(reqs[i])
+					So(err, ShouldBeNil)
+					So(qt, ShouldNotBeNil)
+					So(resp, ShouldNotBeNil)
+					qt.UpdateResp(resp)
+					// Replay to st2
+					err = st2.Replay(reqs[i], resp)
+					So(err, ShouldBeNil)
+				}
+				// Should be in same state
+				for i := range values {
+					var resp1, resp2 *types.Response
+					req = buildRequest(types.ReadQuery, []types.Query{
+						buildQuery(`SELECT v FROM t1 WHERE k=?`, values[i][0]),
+					})
+					_, resp1, err = st1.Query(req)
+					So(err, ShouldBeNil)
+					So(resp1, ShouldNotBeNil)
+					_, resp2, err = st2.Query(req)
+					So(err, ShouldBeNil)
+					So(resp2, ShouldNotBeNil)
+					So(resp1.Payload, ShouldResemble, resp2.Payload)
+				}
+			})
+			Convey("When queries are committed to blocks on state instance #1", func() {
+				var (
+					qt   *QueryTracker
+					reqs = []*types.Request{
+						buildRequest(types.WriteQuery, []types.Query{
+							buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?)`, values[0]...),
+						}),
+						buildRequest(types.WriteQuery, []types.Query{
+							buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?)`, values[1]...),
+							buildQuery(`INSERT INTO t1 (k, v) VALUES (?, ?);
+INSERT INTO t1 (k, v) VALUES (?, ?)`, concat(values[2:4])...),
+						}),
+						buildRequest(types.WriteQuery, []types.Query{
+							buildQuery(`DELETE FROM t1 WHERE k=?`, values[2][0]),
+						}),
+					}
+
+					cmtpos = 0
+					cmtps  = []int{1, len(reqs) - 1}
+					blocks = make([]*types.Block, len(cmtps))
+				)
+				for i := range reqs {
+					var resp *types.Response
+					qt, resp, err = st1.Query(reqs[i])
+					So(err, ShouldBeNil)
+					So(qt, ShouldNotBeNil)
+					So(resp, ShouldNotBeNil)
+					qt.UpdateResp(resp)
+					// Commit block if matches the next commit point
+					if cmtpos < len(cmtps) && i == cmtps[cmtpos] {
+						var qts []*QueryTracker
+						_, qts, err = st1.CommitEx()
+						So(err, ShouldBeNil)
+						So(qts, ShouldNotBeNil)
+						blocks[cmtpos] = &types.Block{
+							QueryTxs: make([]*types.QueryAsTx, len(qts)),
+						}
+						for i, v := range qts {
+							blocks[cmtpos].QueryTxs[i] = &types.QueryAsTx{
+								Request:  v.Req,
+								Response: &v.Resp.Header,
+							}
+						}
+						cmtpos++
+					}
+				}
+				Convey(
+					"The state should report missing parent while replaying later block first",
+					func() {
+						err = st2.ReplayBlock(blocks[len(blocks)-1])
+						So(err, ShouldEqual, ErrMissingParent)
+					},
+				)
+				Convey(
+					"The state should report conflict error while replaying modified query",
+					func() {
+						// Replay by request to st2 first
+						for _, v := range blocks {
+							for _, w := range v.QueryTxs {
+								err = st2.Replay(w.Request, &types.Response{
+									Header: *w.Response,
+								})
+								So(err, ShouldBeNil)
+							}
+						}
+						// Try to replay modified block #0
+						var blockx = &types.Block{
+							QueryTxs: []*types.QueryAsTx{
+								&types.QueryAsTx{
+									Request: &types.Request{
+										Header: types.SignedRequestHeader{
+											DefaultHashSignVerifierImpl: verifier.DefaultHashSignVerifierImpl{
+												DataHash: [32]byte{
+													0, 0, 0, 0, 0, 0, 0, 1,
+													0, 0, 0, 0, 0, 0, 0, 1,
+													0, 0, 0, 0, 0, 0, 0, 1,
+													0, 0, 0, 0, 0, 0, 0, 1,
+												},
+											},
+										},
+									},
+									Response: &types.SignedResponseHeader{
+										ResponseHeader: types.ResponseHeader{
+											LogOffset: blocks[0].QueryTxs[0].Response.LogOffset,
+										},
+									},
+								},
+							},
+						}
+						blockx.QueryTxs[0].Request.Header.DataHash = hash.Hash{0x0, 0x0, 0x0, 0x1}
+						err = st2.ReplayBlock(blockx)
+						So(err, ShouldEqual, ErrQueryConflict)
+					},
+				)
+				Convey(
+					"The state should be reproducible with block replaying in empty instance #2",
+					func() {
+						// Block replaying
+						for i := range blocks {
+							err = st2.ReplayBlock(blocks[i])
+							So(err, ShouldBeNil)
+						}
+						// Should be in same state
+						for i := range values {
+							var resp1, resp2 *types.Response
+							req = buildRequest(types.ReadQuery, []types.Query{
+								buildQuery(`SELECT v FROM t1 WHERE k=?`, values[i][0]),
+							})
+							_, resp1, err = st1.Query(req)
+							So(err, ShouldBeNil)
+							So(resp1, ShouldNotBeNil)
+							_, resp2, err = st2.Query(req)
+							So(err, ShouldBeNil)
+							So(resp2, ShouldNotBeNil)
+							So(resp1.Payload, ShouldResemble, resp2.Payload)
+						}
+					},
+				)
+				Convey(
+					"The state should be reproducible with block replaying in synchronized"+
+						" instance #2",
+					func() {
+						// Replay by request to st2 first
+						for _, v := range blocks {
+							for _, w := range v.QueryTxs {
+								err = st2.Replay(w.Request, &types.Response{
+									Header: *w.Response,
+								})
+								So(err, ShouldBeNil)
+							}
+						}
+						// Block replaying
+						for i := range blocks {
+							err = st2.ReplayBlock(blocks[i])
+							So(err, ShouldBeNil)
+						}
+						// Should be in same state
+						for i := range values {
+							var resp1, resp2 *types.Response
+							req = buildRequest(types.ReadQuery, []types.Query{
+								buildQuery(`SELECT v FROM t1 WHERE k=?`, values[i][0]),
+							})
+							_, resp1, err = st1.Query(req)
+							So(err, ShouldBeNil)
+							So(resp1, ShouldNotBeNil)
+							_, resp2, err = st2.Query(req)
+							So(err, ShouldBeNil)
+							So(resp2, ShouldNotBeNil)
+							So(resp1.Payload, ShouldResemble, resp2.Payload)
+						}
+					},
+				)
+			})
+		})
+	})
+}
diff --git a/xenomint/types/block.go b/xenomint/types/block.go
new file mode 100644
index 000000000..2621786ab
--- /dev/null
+++ b/xenomint/types/block.go
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/merkle"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/types"
+)
+
+//go:generate hsp
+
+// BlockHeader defines a block header.
+type BlockHeader struct {
+	Version     int32
+	Producer    proto.NodeID
+	GenesisHash hash.Hash
+	ParentHash  hash.Hash
+	MerkleRoot  hash.Hash
+	Timestamp   time.Time
+}
+
+// SignedBlockHeader defines a block along with its hasher, signer and verifier.
+type SignedBlockHeader struct {
+	BlockHeader
+	DefaultHashSignVerifierImpl
+}
+
+// Sign signs the block header.
+func (h *SignedBlockHeader) Sign(signer *asymmetric.PrivateKey) error {
+	return h.DefaultHashSignVerifierImpl.Sign(&h.BlockHeader, signer)
+}
+
+// Verify verifies the block header.
+func (h *SignedBlockHeader) Verify() error {
+	return h.DefaultHashSignVerifierImpl.Verify(&h.BlockHeader)
+}
+
+// Block defines a block including a signed block header and its query list.
+type Block struct {
+	SignedBlockHeader
+	ReadQueries  []*types.Ack
+	WriteQueries []*types.Ack
+}
+
+// Sign signs the block.
+func (b *Block) Sign(signer *asymmetric.PrivateKey) (err error) {
+	// Update header fields: generate merkle root from queries
+	var hashes []*hash.Hash
+	for _, v := range b.ReadQueries {
+		h := v.Header.Hash()
+		hashes = append(hashes, &h)
+	}
+	for _, v := range b.WriteQueries {
+		h := v.Header.Hash()
+		hashes = append(hashes, &h)
+	}
+	if err = b.MerkleRoot.SetBytes(merkle.NewMerkle(hashes).GetRoot()[:]); err != nil {
+		return
+	}
+	// Sign block header
+	return b.SignedBlockHeader.Sign(signer)
+}
+
+// Verify verifies the block.
+func (b *Block) Verify() error {
+	// Verify header fields: compare merkle root from queries
+	var hashes []*hash.Hash
+	for _, v := range b.ReadQueries {
+		h := v.Header.Hash()
+		hashes = append(hashes, &h)
+	}
+	for _, v := range b.WriteQueries {
+		h := v.Header.Hash()
+		hashes = append(hashes, &h)
+	}
+	if mroot := merkle.NewMerkle(hashes).GetRoot(); !mroot.IsEqual(
+		&b.SignedBlockHeader.MerkleRoot,
+	) {
+		return ErrMerkleRootNotMatch
+	}
+	// Verify block header signature
+	return b.SignedBlockHeader.Verify()
+}
diff --git a/xenomint/types/block_gen.go b/xenomint/types/block_gen.go
new file mode 100644
index 000000000..4c19a8bf2
--- /dev/null
+++ b/xenomint/types/block_gen.go
@@ -0,0 +1,143 @@
+package types
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	hsp "github.com/CovenantSQL/HashStablePack/marshalhash"
+)
+
+// MarshalHash marshals for hash
+func (z *Block) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 3
+	// map header, size 2
+	o = append(o, 0x83, 0x83, 0x82, 0x82)
+	if oTemp, err := z.SignedBlockHeader.BlockHeader.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.SignedBlockHeader.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x83)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.ReadQueries)))
+	for za0001 := range z.ReadQueries {
+		if z.ReadQueries[za0001] == nil {
+			o = hsp.AppendNil(o)
+		} else {
+			if oTemp, err := z.ReadQueries[za0001].MarshalHash(); err != nil {
+				return nil, err
+			} else {
+				o = hsp.AppendBytes(o, oTemp)
+			}
+		}
+	}
+	o = append(o, 0x83)
+	o = hsp.AppendArrayHeader(o, uint32(len(z.WriteQueries)))
+	for za0002 := range z.WriteQueries {
+		if z.WriteQueries[za0002] == nil {
+			o = hsp.AppendNil(o)
+		} else {
+			if oTemp, err := z.WriteQueries[za0002].MarshalHash(); err != nil {
+				return nil, err
+			} else {
+				o = hsp.AppendBytes(o, oTemp)
+			}
+		}
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *Block) Msgsize() (s int) {
+	s = 1 + 18 + 1 + 12 + z.SignedBlockHeader.BlockHeader.Msgsize() + 28 + z.SignedBlockHeader.DefaultHashSignVerifierImpl.Msgsize() + 12 + hsp.ArrayHeaderSize
+	for za0001 := range z.ReadQueries {
+		if z.ReadQueries[za0001] == nil {
+			s += hsp.NilSize
+		} else {
+			s += z.ReadQueries[za0001].Msgsize()
+		}
+	}
+	s += 13 + hsp.ArrayHeaderSize
+	for za0002 := range z.WriteQueries {
+		if z.WriteQueries[za0002] == nil {
+			s += hsp.NilSize
+		} else {
+			s += z.WriteQueries[za0002].Msgsize()
+		}
+	}
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *BlockHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 6
+	o = append(o, 0x86, 0x86)
+	if oTemp, err := z.GenesisHash.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x86)
+	if oTemp, err := z.ParentHash.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x86)
+	if oTemp, err := z.MerkleRoot.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x86)
+	o = hsp.AppendInt32(o, z.Version)
+	o = append(o, 0x86)
+	if oTemp, err := z.Producer.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x86)
+	o = hsp.AppendTime(o, z.Timestamp)
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *BlockHeader) Msgsize() (s int) {
+	s = 1 + 12 + z.GenesisHash.Msgsize() + 11 + z.ParentHash.Msgsize() + 11 + z.MerkleRoot.Msgsize() + 8 + hsp.Int32Size + 9 + z.Producer.Msgsize() + 10 + hsp.TimeSize
+	return
+}
+
+// MarshalHash marshals for hash
+func (z *SignedBlockHeader) MarshalHash() (o []byte, err error) {
+	var b []byte
+	o = hsp.Require(b, z.Msgsize())
+	// map header, size 2
+	o = append(o, 0x82, 0x82)
+	if oTemp, err := z.BlockHeader.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	o = append(o, 0x82)
+	if oTemp, err := z.DefaultHashSignVerifierImpl.MarshalHash(); err != nil {
+		return nil, err
+	} else {
+		o = hsp.AppendBytes(o, oTemp)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *SignedBlockHeader) Msgsize() (s int) {
+	s = 1 + 12 + z.BlockHeader.Msgsize() + 28 + z.DefaultHashSignVerifierImpl.Msgsize()
+	return
+}
diff --git a/xenomint/types/block_gen_test.go b/xenomint/types/block_gen_test.go
new file mode 100644
index 000000000..9d948edad
--- /dev/null
+++ b/xenomint/types/block_gen_test.go
@@ -0,0 +1,121 @@
+package types
+
+// Code generated by github.com/CovenantSQL/HashStablePack DO NOT EDIT.
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/binary"
+	"testing"
+)
+
+func TestMarshalHashBlock(t *testing.T) {
+	v := Block{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashBlock(b *testing.B) {
+	v := Block{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgBlock(b *testing.B) {
+	v := Block{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashBlockHeader(t *testing.T) {
+	v := BlockHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashBlockHeader(b *testing.B) {
+	v := BlockHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgBlockHeader(b *testing.B) {
+	v := BlockHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
+
+func TestMarshalHashSignedBlockHeader(t *testing.T) {
+	v := SignedBlockHeader{}
+	binary.Read(rand.Reader, binary.BigEndian, &v)
+	bts1, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	bts2, err := v.MarshalHash()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bts1, bts2) {
+		t.Fatal("hash not stable")
+	}
+}
+
+func BenchmarkMarshalHashSignedBlockHeader(b *testing.B) {
+	v := SignedBlockHeader{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalHash()
+	}
+}
+
+func BenchmarkAppendMsgSignedBlockHeader(b *testing.B) {
+	v := SignedBlockHeader{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalHash()
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalHash()
+	}
+}
diff --git a/xenomint/types/block_test.go b/xenomint/types/block_test.go
new file mode 100644
index 000000000..e971bfffe
--- /dev/null
+++ b/xenomint/types/block_test.go
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	"github.com/CovenantSQL/CovenantSQL/crypto/verifier"
+	"github.com/CovenantSQL/CovenantSQL/types"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestBlock(t *testing.T) {
+	Convey("Given a block and a pair of keys", t, func() {
+		var (
+			block = &Block{
+				SignedBlockHeader: SignedBlockHeader{
+					BlockHeader: BlockHeader{},
+				},
+				ReadQueries: []*types.Ack{
+					{
+						Header: types.SignedAckHeader{
+							DefaultHashSignVerifierImpl: verifier.DefaultHashSignVerifierImpl{
+								DataHash: hash.Hash{0x0, 0x0, 0x0, 0x1},
+							},
+						},
+					},
+				},
+				WriteQueries: []*types.Ack{
+					{
+						Header: types.SignedAckHeader{
+							DefaultHashSignVerifierImpl: verifier.DefaultHashSignVerifierImpl{
+								DataHash: hash.Hash{0x0, 0x0, 0x0, 0x2},
+							},
+						},
+					},
+				},
+			}
+			priv, _, err = asymmetric.GenSecp256k1KeyPair()
+		)
+		So(err, ShouldBeNil)
+		So(priv, ShouldNotBeNil)
+		Convey("When the block is signed by the key pair", func() {
+			err = block.Sign(priv)
+			So(err, ShouldBeNil)
+			Convey("The block should be verifiable", func() {
+				err = block.Verify()
+				So(err, ShouldBeNil)
+			})
+			Convey("The object should have data hash", func() {
+				var enc, err = block.BlockHeader.MarshalHash()
+				So(err, ShouldBeNil)
+				So(enc, ShouldNotBeNil)
+				So(block.SignedBlockHeader.Hash(), ShouldEqual, hash.THashH(enc))
+			})
+			Convey("When the queries is modified", func() {
+				block.ReadQueries = append(block.ReadQueries, &types.Ack{
+					Header: types.SignedAckHeader{
+						DefaultHashSignVerifierImpl: verifier.DefaultHashSignVerifierImpl{
+							DataHash: hash.Hash{0x0, 0x0, 0x0, 0x3},
+						},
+					},
+				})
+				Convey("The verifier should return merkle root not match error", func() {
+					err = block.Verify()
+					So(err, ShouldEqual, ErrMerkleRootNotMatch)
+				})
+			})
+		})
+	})
+}
diff --git a/blockproducer/types/common.go b/xenomint/types/common.go
similarity index 81%
rename from blockproducer/types/common.go
rename to xenomint/types/common.go
index 024cc9646..cd4f48a1f 100644
--- a/blockproducer/types/common.go
+++ b/xenomint/types/common.go
@@ -21,20 +21,24 @@ import (
 	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
 )
 
-type marshalHasher interface {
-	MarshalHash() ([]byte, error)
-}
+//go:generate hsp
 
 // DefaultHashSignVerifierImpl defines a default implementation of hashSignVerifier.
 type DefaultHashSignVerifierImpl struct {
-	Hash      hash.Hash
+	DataHash  hash.Hash
 	Signee    *asymmetric.PublicKey
 	Signature *asymmetric.Signature
 }
 
-// GetHash implements hashSignVerifier.GetHash.
-func (i *DefaultHashSignVerifierImpl) GetHash() hash.Hash {
-	return i.Hash
+// marshalHasher is the interface implemented by an object that can be stably
+// marshalled and hashed.
+type marshalHasher interface {
+	MarshalHash() ([]byte, error)
+}
+
+// Hash implements hashSignVerifier.Hash.
+func (i *DefaultHashSignVerifierImpl) Hash() hash.Hash {
+	return i.DataHash
 }
 
 // Sign implements hashSignVerifier.Sign.
@@ -49,7 +53,7 @@ func (i *DefaultHashSignVerifierImpl) Sign(
 	if i.Signature, err = signer.Sign(h[:]); err != nil {
 		return
 	}
-	i.Hash = h
+	i.DataHash = h
 	i.Signee = signer.PubKey()
 	return
 }
@@ -61,12 +65,12 @@ func (i *DefaultHashSignVerifierImpl) Verify(obj marshalHasher) (err error) {
 		return
 	}
 	var h = hash.THashH(enc)
-	if !i.Hash.IsEqual(&h) {
-		err = ErrSignVerification
+	if !i.DataHash.IsEqual(&h) {
+		err = ErrHashValueNotMatch
 		return
 	}
 	if !i.Signature.Verify(h[:], i.Signee) {
-		err = ErrSignVerification
+		err = ErrSignatureNotMatch
 		return
 	}
 	return
diff --git a/blockproducer/types/common_gen.go b/xenomint/types/common_gen.go
similarity index 93%
rename from blockproducer/types/common_gen.go
rename to xenomint/types/common_gen.go
index 9f8cefc8a..8fdb3ee08 100644
--- a/blockproducer/types/common_gen.go
+++ b/xenomint/types/common_gen.go
@@ -32,7 +32,7 @@ func (z *DefaultHashSignVerifierImpl) MarshalHash() (o []byte, err error) {
 		}
 	}
 	o = append(o, 0x83)
-	if oTemp, err := z.Hash.MarshalHash(); err != nil {
+	if oTemp, err := z.DataHash.MarshalHash(); err != nil {
 		return nil, err
 	} else {
 		o = hsp.AppendBytes(o, oTemp)
@@ -54,6 +54,6 @@ func (z *DefaultHashSignVerifierImpl) Msgsize() (s int) {
 	} else {
 		s += z.Signature.Msgsize()
 	}
-	s += 5 + z.Hash.Msgsize()
+	s += 9 + z.DataHash.Msgsize()
 	return
 }
diff --git a/blockproducer/types/common_gen_test.go b/xenomint/types/common_gen_test.go
similarity index 100%
rename from blockproducer/types/common_gen_test.go
rename to xenomint/types/common_gen_test.go
diff --git a/xenomint/types/common_test.go b/xenomint/types/common_test.go
new file mode 100644
index 000000000..76f6c43b7
--- /dev/null
+++ b/xenomint/types/common_test.go
@@ -0,0 +1,100 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/hash"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+var (
+	dummyHash = []byte{
+		0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+		0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+		0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+		0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+	}
+)
+
+type DummyHeader struct{}
+
+func (h *DummyHeader) MarshalHash() ([]byte, error) {
+	return dummyHash, nil
+}
+
+type DummyObject struct {
+	DummyHeader
+	DefaultHashSignVerifierImpl
+}
+
+func (o *DummyObject) Sign(signer *asymmetric.PrivateKey) error {
+	return o.DefaultHashSignVerifierImpl.Sign(&o.DummyHeader, signer)
+}
+
+func (o *DummyObject) Verify() error {
+	return o.DefaultHashSignVerifierImpl.Verify(&o.DummyHeader)
+}
+
+func TestDefaultHashSignVerifierImpl(t *testing.T) {
+	Convey("Given a dummy object and a pair of keys", t, func() {
+		var (
+			obj          = &DummyObject{}
+			priv, _, err = asymmetric.GenSecp256k1KeyPair()
+		)
+		So(err, ShouldBeNil)
+		So(priv, ShouldNotBeNil)
+		Convey("When the object is signed by the key pair", func() {
+			err = obj.Sign(priv)
+			So(err, ShouldBeNil)
+			Convey("The object should be verifiable", func() {
+				err = obj.Verify()
+				So(err, ShouldBeNil)
+			})
+			Convey("The object should have data hash", func() {
+				So(obj.Hash(), ShouldEqual, hash.THashH(dummyHash))
+			})
+			Convey("When the hash is modified", func() {
+				obj.DefaultHashSignVerifierImpl.DataHash = hash.Hash{0x0, 0x0, 0x0, 0x1}
+				Convey("The verifier should return hash value not match error", func() {
+					err = obj.Verify()
+					So(err, ShouldEqual, ErrHashValueNotMatch)
+				})
+			})
+			Convey("When the signee is modified", func() {
+				var _, pub, err = asymmetric.GenSecp256k1KeyPair()
+				So(err, ShouldBeNil)
+				obj.DefaultHashSignVerifierImpl.Signee = pub
+				Convey("The verifier should return signature not match error", func() {
+					err = obj.Verify()
+					So(err, ShouldEqual, ErrSignatureNotMatch)
+				})
+			})
+			Convey("When the signature is modified", func() {
+				var val = obj.DefaultHashSignVerifierImpl.Signature.R
+				val.Add(val, big.NewInt(1))
+				Convey("The verifier should return signature not match error", func() {
+					err = obj.Verify()
+					So(err, ShouldEqual, ErrSignatureNotMatch)
+				})
+			})
+		})
+	})
+}
diff --git a/worker/types/doc.go b/xenomint/types/doc.go
similarity index 92%
rename from worker/types/doc.go
rename to xenomint/types/doc.go
index cf6b420cc..28c02e239 100644
--- a/worker/types/doc.go
+++ b/xenomint/types/doc.go
@@ -14,7 +14,4 @@
  * limitations under the License.
  */
 
-/*
-Package types defines miner node export types.
-*/
 package types
diff --git a/xenomint/types/errors.go b/xenomint/types/errors.go
new file mode 100644
index 000000000..10bb609f8
--- /dev/null
+++ b/xenomint/types/errors.go
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"errors"
+)
+
+var (
+	// ErrMerkleRootNotMatch indicates the merkle root not match error from verifier.
+	ErrMerkleRootNotMatch = errors.New("merkle root not match")
+	// ErrHashValueNotMatch indicates the hash value not match error from verifier.
+	ErrHashValueNotMatch = errors.New("hash value not match")
+	// ErrSignatureNotMatch indicates the signature not match error from verifier.
+	ErrSignatureNotMatch = errors.New("signature not match")
+)
diff --git a/xenomint/types/xxx_test.go b/xenomint/types/xxx_test.go
new file mode 100644
index 000000000..04c291621
--- /dev/null
+++ b/xenomint/types/xxx_test.go
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package types
+
+import (
+	"math/rand"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
+)
+
+func setup() {
+	rand.Seed(time.Now().UnixNano())
+	log.SetOutput(os.Stdout)
+	log.SetLevel(log.DebugLevel)
+}
+
+func teardown() {
+}
+
+func TestMain(m *testing.M) {
+	os.Exit(func() int {
+		setup()
+		defer teardown()
+		return m.Run()
+	}())
+}
diff --git a/xenomint/xxx_test.go b/xenomint/xxx_test.go
new file mode 100644
index 000000000..aabe8fe80
--- /dev/null
+++ b/xenomint/xxx_test.go
@@ -0,0 +1,221 @@
+/*
+ * Copyright 2018 The CovenantSQL Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xenomint
+
+import (
+	"io/ioutil"
+	"math/rand"
+	"os"
+	"path"
+	//"runtime/trace"
+	"sync"
+	"syscall"
+	"testing"
+	"time"
+
+	ca "github.com/CovenantSQL/CovenantSQL/crypto/asymmetric"
+	"github.com/CovenantSQL/CovenantSQL/crypto/kms"
+	pc "github.com/CovenantSQL/CovenantSQL/pow/cpuminer"
+	"github.com/CovenantSQL/CovenantSQL/proto"
+	"github.com/CovenantSQL/CovenantSQL/types"
+	"github.com/CovenantSQL/CovenantSQL/utils/log"
+)
+
+const (
+	benchmarkQueriesPerBlock = 100
+
+	benchmarkRPCName    = "BENCH"
+	benchmarkDatabaseID = "0x0"
+
+	benchmarkVNum = 3
+	benchmarkVLen = 333
+	// benchmarkKeySpace defines the key space for benchmarking.
+	//
+	// We will have `benchmarkKeySpace` preserved records in the generated testing table and
+	// another `benchmarkKeySpace` constructed incoming records returned from the setup function.
+	benchmarkKeySpace = 100000
+)
+
+var (
+	testingDataDir            string
+	testingTraceFile          *os.File
+	testingPrivateKeyFile     string
+	testingPublicKeyStoreFile string
+	testingNonceDifficulty    int
+
+	testingPrivateKey *ca.PrivateKey
+	testingPublicKey  *ca.PublicKey
+
+	testingMasterKey = []byte(`?08Rl%WUih4V0H+c`)
+)
+
+func buildQuery(query string, args ...interface{}) types.Query {
+	var nargs = make([]types.NamedArg, len(args))
+	for i := range args {
+		nargs[i] = types.NamedArg{
+			Name:  "",
+			Value: args[i],
+		}
+	}
+	return types.Query{
+		Pattern: query,
+		Args:    nargs,
+	}
+}
+
+func buildRequest(qt types.QueryType, qs []types.Query) *types.Request {
+	var (
+		id  proto.NodeID
+		err error
+	)
+	if id, err = kms.GetLocalNodeID(); err != nil {
+		id = proto.NodeID("00000000000000000000000000000000")
+	}
+	return &types.Request{
+		Header: types.SignedRequestHeader{
+			RequestHeader: types.RequestHeader{
+				NodeID:    id,
+				Timestamp: time.Now().UTC(),
+				QueryType: qt,
+			},
+		},
+		Payload: types.RequestPayload{Queries: qs},
+	}
+}
+
+func concat(args [][]interface{}) (ret []interface{}) {
+	var (
+		tlen int
+	)
+	for _, v := range args {
+		tlen += len(v)
+	}
+	ret = make([]interface{}, 0, tlen)
+	for _, v := range args {
+		ret = append(ret, v...)
+	}
+	return
+}
+
+func createNodesWithPublicKey(
+	pub *ca.PublicKey, diff int, num int) (nis []proto.Node, err error,
+) {
+	var (
+		nic   = make(chan pc.NonceInfo)
+		block = pc.MiningBlock{Data: pub.Serialize(), NonceChan: nic, Stop: nil}
+		miner = pc.NewCPUMiner(nil)
+		wg    = &sync.WaitGroup{}
+
+		next pc.Uint256
+		ni   pc.NonceInfo
+	)
+
+	defer func() {
+		wg.Wait()
+		close(nic)
+	}()
+
+	nis = make([]proto.Node, num)
+	for i := range nis {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			miner.ComputeBlockNonce(block, next, diff)
+		}()
+		ni = <-nic
+		nis[i] = proto.Node{
+			ID:        proto.NodeID(ni.Hash.String()),
+			Nonce:     ni.Nonce,
+			PublicKey: pub,
+		}
+		next = ni.Nonce
+		next.Inc()
+	}
+
+	return
+}
+
+func setup() {
+	const minNoFile uint64 = 4096
+	var (
+		err error
+		lmt syscall.Rlimit
+	)
+
+	if testingDataDir, err = ioutil.TempDir("", "CovenantSQL"); err != nil {
+		panic(err)
+	}
+
+	rand.Seed(time.Now().UnixNano())
+
+	// Set NOFILE limit
+	if err = syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lmt); err != nil {
+		panic(err)
+	}
+	if lmt.Max < minNoFile {
+		panic("insufficient max RLIMIT_NOFILE")
+	}
+	lmt.Cur = lmt.Max
+	if err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &lmt); err != nil {
+		panic(err)
+	}
+
+	// Initialze kms
+	testingNonceDifficulty = 2
+	testingPrivateKeyFile = path.Join(testingDataDir, "private.key")
+	testingPublicKeyStoreFile = path.Join(testingDataDir, "public.keystore")
+	if testingPrivateKey, testingPublicKey, err = ca.GenSecp256k1KeyPair(); err != nil {
+		panic(err)
+	}
+	kms.Unittest = true
+	kms.SetLocalKeyPair(testingPrivateKey, testingPublicKey)
+	if err = kms.SavePrivateKey(
+		testingPrivateKeyFile, testingPrivateKey, testingMasterKey,
+	); err != nil {
+		panic(err)
+	}
+
+	// Setup runtime trace for testing
+	//if testingTraceFile, err = ioutil.TempFile("", "CovenantSQL.trace."); err != nil {
+	//	panic(err)
+	//}
+	//if err = trace.Start(testingTraceFile); err != nil {
+	//	panic(err)
+	//}
+
+	log.SetOutput(os.Stdout)
+	log.SetLevel(log.DebugLevel)
+}
+
+func teardown() {
+	//trace.Stop()
+	var err error
+	//if err = testingTraceFile.Close(); err != nil {
+	//	panic(err)
+	//}
+	if err = os.RemoveAll(testingDataDir); err != nil {
+		panic(err)
+	}
+}
+
+func TestMain(m *testing.M) {
+	os.Exit(func() int {
+		setup()
+		defer teardown()
+		return m.Run()
+	}())
+}