// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.

// This source code is licensed under both the GPLv2 (found in the

// COPYING file in the root directory) and Apache 2.0 License

// (found in the LICENSE.Apache file in the root directory).

package org.rocksdb;

import static org.assertj.core.api.Assertions.assertThat;

import java.util.Arrays;

import java.util.List;

import org.junit.ClassRule;

import org.junit.Rule;

import org.junit.Test;

import org.junit.rules.TemporaryFolder;

public class SnapshotTest {

@ClassRule

public static final RocksNativeLibraryResource ROCKS_NATIVE_LIBRARY_RESOURCE =

new RocksNativeLibraryResource();

@Rule

public TemporaryFolder dbFolder = new TemporaryFolder();

@Test

public void snapshots() throws RocksDBException {

try (final Options options = new Options().setCreateIfMissing(true);

final RocksDB db = RocksDB.open(options,

dbFolder.getRoot().getAbsolutePath())) {

db.put("key".getBytes(), "value".getBytes());

// Get new Snapshot of database

try (final Snapshot snapshot = db.getSnapshot()) {

assertThat(snapshot.getSequenceNumber()).isGreaterThan(0);

assertThat(snapshot.getSequenceNumber()).isEqualTo(1);

try (final ReadOptions readOptions = new ReadOptions()) {

// set snapshot in ReadOptions

readOptions.setSnapshot(snapshot);

// retrieve key value pair

assertThat(new String(db.get("key".getBytes()))).

isEqualTo("value");

// retrieve key value pair created before

// the snapshot was made

assertThat(new String(db.get(readOptions,

"key".getBytes()))).isEqualTo("value");

// add new key/value pair

db.put("newkey".getBytes(), "newvalue".getBytes());

final GetWithMetadataResult createdAfterSnapshot =

db.getWithMetadata(readOptions, "newkey".getBytes());

assertThat(createdAfterSnapshot.value).isNull();

assertThat(createdAfterSnapshot.newerVersionPresent).isTrue();

final List<GetWithMetadataResult> metadataResults = db.multiGetWithMetadata(

readOptions, Arrays.asList("key".getBytes(), "newkey".getBytes()));

assertThat(new String(metadataResults.get(0).value)).isEqualTo("value");

assertThat(metadataResults.get(0).newerVersionPresent).isFalse();

assertThat(metadataResults.get(1).value).isNull();

assertThat(metadataResults.get(1).newerVersionPresent).isTrue();

// using no snapshot the latest db entries

// will be taken into account

assertThat(new String(db.get("newkey".getBytes()))).

isEqualTo("newvalue");

// snapshopot was created before newkey

assertThat(db.get(readOptions, "newkey".getBytes())).

isNull();

// Retrieve snapshot from read options

try (final Snapshot sameSnapshot = readOptions.snapshot()) {

readOptions.setSnapshot(sameSnapshot);

// results must be the same with new Snapshot

// instance using the same native pointer

assertThat(new String(db.get(readOptions,

"key".getBytes()))).isEqualTo("value");

// update key value pair to newvalue

db.put("key".getBytes(), "newvalue".getBytes());

// read with previously created snapshot will

// read previous version of key value pair

assertThat(new String(db.get(readOptions,

"key".getBytes()))).isEqualTo("value");

// read for newkey using the snapshot must be

// null

assertThat(db.get(readOptions, "newkey".getBytes())).

isNull();

// setting null to snapshot in ReadOptions leads

// to no Snapshot being used.

readOptions.setSnapshot(null);

assertThat(new String(db.get(readOptions,

"newkey".getBytes()))).isEqualTo("newvalue");

// release Snapshot

db.releaseSnapshot(snapshot);

}

}

}

}

}

@Test

public void iteratorWithSnapshot() throws RocksDBException {

try (final Options options = new Options().setCreateIfMissing(true);

final RocksDB db = RocksDB.open(options,

dbFolder.getRoot().getAbsolutePath())) {

db.put("key".getBytes(), "value".getBytes());

// Get new Snapshot of database

// set snapshot in ReadOptions

try (final Snapshot snapshot = db.getSnapshot();

final ReadOptions readOptions =

new ReadOptions().setSnapshot(snapshot)) {

db.put("key2".getBytes(), "value2".getBytes());

// iterate over current state of db

try (final RocksIterator iterator = db.newIterator()) {

iterator.seekToFirst();

assertThat(iterator.isValid()).isTrue();

assertThat(iterator.key()).isEqualTo("key".getBytes());

iterator.next();

assertThat(iterator.isValid()).isTrue();

assertThat(iterator.key()).isEqualTo("key2".getBytes());

iterator.next();

assertThat(iterator.isValid()).isFalse();

}

// iterate using a snapshot

try (final RocksIterator snapshotIterator =

db.newIterator(readOptions)) {

snapshotIterator.seekToFirst();

assertThat(snapshotIterator.isValid()).isTrue();

assertThat(snapshotIterator.key()).isEqualTo("key".getBytes());

snapshotIterator.next();

assertThat(snapshotIterator.isValid()).isFalse();

}

// release Snapshot

db.releaseSnapshot(snapshot);

}

}

}

@Test

public void iteratorWithSnapshotOnColumnFamily() throws RocksDBException {

try (final Options options = new Options()

.setCreateIfMissing(true);

final RocksDB db = RocksDB.open(options,

dbFolder.getRoot().getAbsolutePath())) {

db.put("key".getBytes(), "value".getBytes());

// Get new Snapshot of database

// set snapshot in ReadOptions

try (final Snapshot snapshot = db.getSnapshot();

final ReadOptions readOptions = new ReadOptions()

.setSnapshot(snapshot)) {

db.put("key2".getBytes(), "value2".getBytes());

// iterate over current state of column family

try (final RocksIterator iterator = db.newIterator(

db.getDefaultColumnFamily())) {

iterator.seekToFirst();

assertThat(iterator.isValid()).isTrue();

assertThat(iterator.key()).isEqualTo("key".getBytes());

iterator.next();

assertThat(iterator.isValid()).isTrue();

assertThat(iterator.key()).isEqualTo("key2".getBytes());

iterator.next();

assertThat(iterator.isValid()).isFalse();

}

// iterate using a snapshot on default column family

try (final RocksIterator snapshotIterator = db.newIterator(

db.getDefaultColumnFamily(), readOptions)) {

snapshotIterator.seekToFirst();

assertThat(snapshotIterator.isValid()).isTrue();

assertThat(snapshotIterator.key()).isEqualTo("key".getBytes());

snapshotIterator.next();

assertThat(snapshotIterator.isValid()).isFalse();

// release Snapshot

db.releaseSnapshot(snapshot);

}

}

}

}

}