# Reference configuration for the DataStax Java driver for Apache Cassandra®.

#

# Unless you use a custom mechanism to load your configuration (see

# SessionBuilder.withConfigLoader), all the values declared here will be used as defaults. You can

# place your own `application.conf` in the classpath to override them.

#

# Options are classified into two categories:

# - basic: what is most likely to be customized first when kickstarting a new application.

# - advanced: more elaborate tuning options, or "expert"-level customizations.

#

# This file is in HOCON format, see https://github.com/typesafehub/config/blob/master/HOCON.md.

datastax-java-driver {

# BASIC OPTIONS ----------------------------------------------------------------------------------

# The contact points to use for the initial connection to the cluster.

#

# These are addresses of Cassandra nodes that the driver uses to discover the cluster topology.

# Only one contact point is required (the driver will retrieve the address of the other nodes

# automatically), but it is usually a good idea to provide more than one contact point, because if

# that single contact point is unavailable, the driver cannot initialize itself correctly.

#

# This must be a list of strings with each contact point specified as "host:port". If the host is

# a DNS name that resolves to multiple A-records, all the corresponding addresses will be used. Do

# not use "localhost" as the host name (since it resolves to both IPv4 and IPv6 addresses on some

# platforms).

#

# Note that Cassandra 3 and below requires all nodes in a cluster to share the same port (see

# CASSANDRA-7544).

#

# Contact points can also be provided programmatically when you build a cluster instance. If both

# are specified, they will be merged. If both are absent, the driver will default to

# 127.0.0.1:9042.

#

# Required: no

# Modifiable at runtime: no

# Overridable in a profile: no

// basic.contact-points = [ "127.0.0.1:9042", "127.0.0.2:9042" ]

# A name that uniquely identifies the driver instance created from this configuration. This is

# used as a prefix for log messages and metrics.

#

# If this option is absent, the driver will generate an identifier composed of the letter 's'

# followed by an incrementing counter. If you provide a different value, try to keep it short to

# keep the logs readable. Also, make sure it is unique: reusing the same value will not break the

# driver, but it will mix up the logs and metrics.

#

# Required: no

# Modifiable at runtime: no

# Overridable in a profile: no

// basic.session-name = my_session

# The name of the keyspace that the session should initially be connected to.

#

# This expects the same format as in a CQL query: case-sensitive names must be quoted (note that

# the quotes must be escaped in HOCON format). For example:

# session-keyspace = case_insensitive_name

# session-keyspace = \"CaseSensitiveName\"

#

# If this option is absent, the session won't be connected to any keyspace, and you'll have to

# either qualify table names in your queries, or use the per-query keyspace feature available in

# Cassandra 4 and above (see Request.getKeyspace()).

#

# This can also be provided programatically in CqlSessionBuilder.

#

# Required: no

# Modifiable at runtime: no

# Overridable in a profile: no

// basic.session-keyspace = my_keyspace

# How often the driver tries to reload the configuration.

#

# To disable periodic reloading, set this to 0.

#

# Required: yes (unless you pass a different ConfigLoader to the session builder).

# Modifiable at runtime: yes, the new value will be used after the next time the configuration

# gets reloaded.

# Overridable in a profile: no

basic.config-reload-interval = 5 minutes

basic.request {

# How long the driver waits for a request to complete. This is a global limit on the duration of

# a session.execute() call, including any internal retries the driver might do.

#

# By default, this value is set pretty high to ensure that DDL queries don't time out, in order

# to provide the best experience for new users trying the driver with the out-of-the-box

# configuration.

# For any serious deployment, we recommend that you use separate configuration profiles for DDL

# and DML; you can then set the DML timeout much lower (down to a few milliseconds if needed).

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for requests issued after the change.

# Overridable in a profile: yes

timeout = 2 seconds

# The consistency level.

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for requests issued after the change.

# Overridable in a profile: yes

consistency = LOCAL_ONE

# The page size. This controls how many rows will be retrieved simultaneously in a single

# network roundtrip (the goal being to avoid loading too many results in memory at the same

# time). If there are more results, additional requests will be used to retrieve them (either

# automatically if you iterate with the sync API, or explicitly with the async API's

# fetchNextPage method).

# If the value is 0 or negative, it will be ignored and the request will not be paged.

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for requests issued after the change.

# Overridable in a profile: yes

page-size = 5000

# The serial consistency level.

# The allowed values are SERIAL and LOCAL_SERIAL.

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for requests issued after the change.

# Overridable in a profile: yes

serial-consistency = SERIAL

# The default idempotence of a request, that will be used for all `Request` instances where

# `isIdempotent()` returns null.

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for requests issued after the change.

# Overridable in a profile: yes

default-idempotence = false

}

# The policy that decides the "query plan" for each query; that is, which nodes to try as

# coordinators, and in which order.

#

# Required: yes

# Modifiable at runtime: no (but custom implementations may elect to watch configuration changes

# and allow child options to be changed at runtime).

# Overridable in a profile: yes. Note that the driver creates as few instances as possible: if a

# named profile inherits from the default profile, or if two sibling profiles have the exact

# same configuration, they will share a single policy instance at runtime.

# If there are multiple load balancing policies in a single driver instance, they work together

# in the following way:

# - each request gets a query plan from its profile's policy (or the default policy if the

# request has no profile, or the profile does not override the policy).

# - when the policies assign distances to nodes, the driver uses the closest assigned distance

# for any given node.

basic.load-balancing-policy {

# The class of the policy. If it is not qualified, the driver assumes that it resides in the

# package com.datastax.oss.driver.internal.core.loadbalancing.

#

# The driver provides a single implementation out of the box: DefaultLoadBalancingPolicy.

#

# You can also specify a custom class that implements LoadBalancingPolicy and has a public

# constructor with two arguments: the DriverContext and a String representing the profile name.

class = DefaultLoadBalancingPolicy

# The datacenter that is considered "local": the default policy will only include nodes from

# this datacenter in its query plans.

#

# This option can only be absent if you specified no contact points: in that case, the driver

# defaults to 127.0.0.1:9042, and that node's datacenter is used as the local datacenter.

#

# As soon as you provide contact points (either through the configuration or through the cluster

# builder), you must define the local datacenter explicitly, and initialization will fail if

# this property is absent. In addition, all contact points should be from this datacenter;

# warnings will be logged for nodes that are from a different one.

// local-datacenter = datacenter1

# A custom filter to include/exclude nodes.

#

# This option is not required; if present, it must be the fully-qualified name of a class that

# implements `java.util.function.Predicate<Node>`, and has a public constructor taking a single

# `DriverContext` argument.

#

# Alternatively, you can pass an instance of your filter to

# CqlSession.builder().withNodeFilter(). In that case, this option will be ignored.

#

# The predicate's `test(Node)` method will be invoked each time the policy processes a

# topology or state change: if it returns false, the node will be set at distance IGNORED

# (meaning the driver won't ever connect to it), and never included in any query plan.

// filter.class=

}

# ADVANCED OPTIONS -------------------------------------------------------------------------------

advanced.connection {

# The timeout to use for internal queries that run as part of the initialization process, just

# after we open a connection. If this timeout fires, the initialization of the connection will

# fail. If this is the first connection ever, the driver will fail to initialize as well,

# otherwise it will retry the connection later.

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for connections created after the

# change.

# Overridable in a profile: no

init-query-timeout = 500 milliseconds

# The timeout to use when the driver changes the keyspace on a connection at runtime (this

# happens when the client issues a `USE ...` query, and all connections belonging to the current

# session need to be updated).

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for connections created after the

# change.

# Overridable in a profile: no

set-keyspace-timeout = ${datastax-java-driver.advanced.connection.init-query-timeout}

# The driver maintains a connection pool to each node, according to the distance assigned to it

# by the load balancing policy. If the distance is IGNORED, no connections are maintained.

pool {

local {

# The number of connections in the pool.

#

# Required: yes

# Modifiable at runtime: yes; when the change is detected, all active pools will be notified

# and will adjust their size.

# Overridable in a profile: no

size = 1

}

remote {

size = 1

}

}

# The maximum number of requests that can be executed concurrently on a connection. This must be

# between 1 and 32768.

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for connections created after the

# change.

# Overridable in a profile: no

max-requests-per-connection = 1024

# The maximum number of "orphaned" requests before a connection gets closed automatically.

#

# Sometimes the driver writes to a node but stops listening for a response (for example if the

# request timed out, or was completed by another node). But we can't safely reuse the stream id

# on this connection until we know for sure that the server is done with it. Therefore the id is

# marked as "orphaned" until we get a response from the node.

#

# If the response never comes (or is lost because of a network issue), orphaned ids can

# accumulate over time, eventually affecting the connection's throughput. So we monitor them

# and close the connection above a given threshold (the pool will replace it).

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for connections created after the

# change.

# Overridable in a profile: no

max-orphan-requests = 24576

# Whether to log non-fatal errors when the driver tries to open a new connection.

#

# This error as recoverable, as the driver will try to reconnect according to the reconnection

# policy. Therefore some users see them as unnecessary clutter in the logs. On the other hand,

# those logs can be handy to debug a misbehaving node.

#

# Note that some type of errors are always logged, regardless of this option:

# - protocol version mismatches (the node gets forced down)

# - when the cluster name in system.local doesn't match the other nodes (the node gets forced

# down)

# - authentication errors (will be retried)

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for connections created after the

# change.

# Overridable in a profile: no

warn-on-init-error = true

}

# Whether to schedule reconnection attempts if all contact points are unreachable on the first

# initialization attempt.

#

# If this is true, the driver will retry according to the reconnection policy. The

# `SessionBuilder.build()` call -- or the future returned by `SessionBuilder.buildAsync()` --

# won't complete until a contact point has been reached.

#

# If this is false and no contact points are available, the driver will fail with an

# AllNodesFailedException.

#

# Required: yes

# Modifiable at runtime: no

# Overridable in a profile: no

advanced.reconnect-on-init = false

# The policy that controls how often the driver tries to re-establish connections to down nodes.

#

# Required: yes

# Modifiable at runtime: no (but custom implementations may elect to watch configuration changes

# and allow child options to be changed at runtime).

# Overridable in a profile: no

advanced.reconnection-policy {

# The class of the policy. If it is not qualified, the driver assumes that it resides in the

# package com.datastax.oss.driver.internal.core.connection.

#

# The driver provides two implementations out of the box: ExponentialReconnectionPolicy and

# ConstantReconnectionPolicy.

#

# You can also specify a custom class that implements ReconnectionPolicy and has a public

# constructor with a DriverContext argument.

class = ExponentialReconnectionPolicy

# ExponentialReconnectionPolicy starts with the base delay, and doubles it after each failed

# reconnection attempt, up to the maximum delay (after that it stays constant).

#

# ConstantReconnectionPolicy only uses the base-delay value, the interval never changes.

base-delay = 1 second

max-delay = 60 seconds

}

# The policy that controls if the driver retries requests that have failed on one node.

#

# Required: yes

# Modifiable at runtime: no (but custom implementations may elect to watch configuration changes

# and allow child options to be changed at runtime).

# Overridable in a profile: yes. Note that the driver creates as few instances as possible: if a

# named profile inherits from the default profile, or if two sibling profiles have the exact

# same configuration, they will share a single policy instance at runtime.

advanced.retry-policy {

# The class of the policy. If it is not qualified, the driver assumes that it resides in the

# package com.datastax.oss.driver.internal.core.retry.

#

# The driver provides a single implementation out of the box: DefaultRetryPolicy.

#

# You can also specify a custom class that implements RetryPolicy and has a public constructor

# with two arguments: the DriverContext and a String representing the profile name.

class = DefaultRetryPolicy

}

# The policy that controls if the driver pre-emptively tries other nodes if a node takes too long

# to respond.

#

# Required: yes

# Modifiable at runtime: no (but custom implementations may elect to watch configuration changes

# and allow child options to be changed at runtime).

# Overridable in a profile: yes. Note that the driver creates as few instances as possible: if a

# named profile inherits from the default profile, or if two sibling profiles have the exact

# same configuration, they will share a single policy instance at runtime.

advanced.speculative-execution-policy {

# The class of the policy. If it is not qualified, the driver assumes that it resides in the

# package com.datastax.oss.driver.internal.core.specex.

#

# The following implementations are available out of the box:

# - NoSpeculativeExecutionPolicy: never schedule any speculative execution

# - ConstantSpeculativeExecutionPolicy: schedule executions based on constant delays. This

# requires the `max-executions` and `delay` options below.

#

# You can also specify a custom class that implements SpeculativeExecutionPolicy and has a

# public constructor with two arguments: the DriverContext and a String representing the

# profile name.

class = NoSpeculativeExecutionPolicy

# The maximum number of executions (including the initial, non-speculative execution).

# This must be at least one.

// max-executions = 3

# The delay between each execution. 0 is allowed, and will result in all executions being sent

# simultaneously when the request starts.

# Note that sub-millisecond precision is not supported, any excess precision information will be

# dropped; in particular, delays of less than 1 millisecond are equivalent to 0.

# This must be positive or 0.

// delay = 100 milliseconds

}

# The component that handles authentication on each new connection.

#

# Required: no. If the 'class' child option is absent, no authentication will occur.

# Modifiable at runtime: no

# Overridable in a profile: no

advanced.auth-provider {

# The class of the provider. If it is not qualified, the driver assumes that it resides in the

# package com.datastax.oss.driver.internal.core.auth.

#

# The driver provides a single implementation out of the box: PlainTextAuthProvider, that uses

# plain-text credentials. It requires the `username` and `password` options below.

#

# You can also specify a custom class that implements AuthProvider and has a public

# constructor with a DriverContext argument.

// class = PlainTextAuthProvider

# Sample configuration for the plain-text provider:

// username = cassandra

// password = cassandra

}

# The SSL engine factory that will initialize an SSL engine for each new connection to a server.

#

# Required: no. If the 'class' child option is absent, SSL won't be activated.

# Modifiable at runtime: no

# Overridable in a profile: no

advanced.ssl-engine-factory {

# The class of the factory. If it is not qualified, the driver assumes that it resides in the

# package com.datastax.oss.driver.internal.core.ssl.

#

# The driver provides a single implementation out of the box: DefaultSslEngineFactory, that uses

# the JDK's built-in SSL implementation.

#

# You can also specify a custom class that implements SslEngineFactory and has a public

# constructor with a DriverContext argument.

// class = DefaultSslEngineFactory

# Sample configuration for the default SSL factory:

# The cipher suites to enable when creating an SSLEngine for a connection.

# This property is optional. If it is not present, the driver won't explicitly enable cipher

# suites on the engine, which according to the JDK documentations results in "a minimum quality

# of service".

// cipher-suites = [ "TLS_RSA_WITH_AES_128_CBC_SHA", "TLS_RSA_WITH_AES_256_CBC_SHA" ]

# Whether or not to require validation that the hostname of the server certificate's common

# name matches the hostname of the server being connected to.

hostname-validation = false

# The locations and passwords used to access truststore and keystore contents.

# These properties are optional. If either truststore-path or keystore-path are specified,

# the driver builds an SSLContext from these files. If neither option is specified, the

# default SSLContext is used, which is based on system property configuration.

// truststore-path = /path/to/client.truststore

// truststore-password = password123

// keystore-path = /path/to/client.keystore

// keystore-password = password123

}

# The generator that assigns a microsecond timestamp to each request.

#

# Required: yes

# Modifiable at runtime: no (but custom implementations may elect to watch configuration changes

# and allow child options to be changed at runtime).

# Overridable in a profile: yes. Note that the driver creates as few instances as possible: if a

# named profile inherits from the default profile, or if two sibling profiles have the exact

# same configuration, they will share a single generator instance at runtime.

advanced.timestamp-generator {

# The class of the generator. If it is not qualified, the driver assumes that it resides in the

# package com.datastax.oss.driver.internal.core.time.

#

# The driver provides the following implementations out of the box:

# - AtomicTimestampGenerator: timestamps are guaranteed to be unique across all client threads.

# - ThreadLocalTimestampGenerator: timestamps that are guaranteed to be unique within each

# thread only.

# - ServerSideTimestampGenerator: do not generate timestamps, let the server assign them.

#

# You can also specify a custom class that implements TimestampGenerator and has a public

# constructor with two arguments: the DriverContext and a String representing the profile name.

class = AtomicTimestampGenerator

# To guarantee that queries are applied on the server in the same order as the client issued

# them, timestamps must be strictly increasing. But this means that, if the driver sends more

# than one query per microsecond, timestamps will drift in the future. While this could happen

# occasionally under high load, it should not be a regular occurrence. Therefore the built-in

# implementations log a warning to detect potential issues.

drift-warning {

# How far in the future timestamps are allowed to drift before the warning is logged.

# If it is undefined or set to 0, warnings are disabled.

threshold = 1 second

# How often the warning will be logged if timestamps keep drifting above the threshold.

interval = 10 seconds

}

# Whether to force the driver to use Java's millisecond-precision system clock.

# If this is false, the driver will try to access the microsecond-precision OS clock via native

# calls (and fallback to the Java one if the native calls fail).

# Unless you explicitly want to avoid native calls, there's no reason to change this.

force-java-clock = false

}

# A session-wide component that tracks the outcome of requests.

#

# Required: yes

# Modifiable at runtime: no (but custom implementations may elect to watch configuration changes

# and allow child options to be changed at runtime).

# Overridable in a profile: no

advanced.request-tracker {

# The class of the tracker. If it is not qualified, the driver assumes that it resides in the

# package com.datastax.oss.driver.internal.core.tracker.

#

# The driver provides the following implementations out of the box:

# - NoopRequestTracker: does nothing.

# - RequestLogger: logs requests (see the parameters below).

#

# You can also specify a custom class that implements RequestTracker and has a public

# constructor with a DriverContext argument.

class = NoopRequestTracker

# Parameters for RequestLogger. All of them can be overridden in a profile, and changed at

# runtime (the new values will be taken into account for requests logged after the change).

logs {

# Whether to log successful requests.

// success.enabled = true

slow {

# The threshold to classify a successful request as "slow". If this is unset, all successful

# requests will be considered as normal.

// threshold = 1 second

# Whether to log slow requests.

// enabled = true

}

# Whether to log failed requests.

// error.enabled = true

# The maximum length of the query string in the log message. If it is longer than that, it

# will be truncated.

// max-query-length = 500

# Whether to log bound values in addition to the query string.

// show-values = true

# The maximum length for bound values in the log message. If the formatted representation of a

# value is longer than that, it will be truncated.

// max-value-length = 50

# The maximum number of bound values to log. If a request has more values, the list of values

# will be truncated.

// max-values = 50

# Whether to log stack traces for failed queries. If this is disabled, the log will just

# include the exception's string representation (generally the class name and message).

// show-stack-traces = true

}

}

# A session-wide component that controls the rate at which requests are executed.

#

# Implementations vary, but throttlers generally track a metric that represents the level of

# utilization of the session, and prevent new requests from starting when that metric exceeds a

# threshold. Pending requests may be enqueued and retried later.

#

# From the public API's point of view, this process is mostly transparent: any time that the

# request is throttled is included in the session.execute() or session.executeAsync() call.

# Similarly, the request timeout encompasses throttling: the timeout starts ticking before the

# throttler has started processing the request; a request may time out while it is still in the

# throttler's queue, before the driver has even tried to send it to a node.

#

# The only visible effect is that a request may fail with a RequestThrottlingException, if the

# throttler has determined that it can neither allow the request to proceed now, nor enqueue it;

# this indicates that your session is overloaded.

#

# Required: yes

# Modifiable at runtime: no (but custom implementations may elect to watch configuration changes

# and allow child options to be changed at runtime).

# Overridable in a profile: no

advanced.throttler {

# The class of the throttler. If it is not qualified, the driver assumes that it resides in

# the package com.datastax.oss.driver.internal.core.session.throttling.

#

# The driver provides the following implementations out of the box:

#

# - PassThroughRequestThrottler: does not perform any kind of throttling, all requests are

# allowed to proceed immediately. Required options: none.

#

# - ConcurrencyLimitingRequestThrottler: limits the number of requests that can be executed in

# parallel. Required options: max-concurrent-requests, max-queue-size.

#

# - RateLimitingRequestThrottler: limits the request rate per second. Required options:

# max-requests-per-second, max-queue-size, drain-interval.

#

# You can also specify a custom class that implements RequestThrottler and has a public

# constructor with a DriverContext argument.

class = PassThroughRequestThrottler

# The maximum number of requests that can be enqueued when the throttling threshold is exceeded.

# Beyond that size, requests will fail with a RequestThrottlingException.

// max-queue-size = 10000

# The maximum number of requests that are allowed to execute in parallel.

# Only used by ConcurrencyLimitingRequestThrottler.

// max-concurrent-requests = 10000

# The maximum allowed request rate.

# Only used by RateLimitingRequestThrottler.

// max-requests-per-second = 10000

# How often the throttler attempts to dequeue requests. This is the only way for rate-based

# throttling, because the completion of an active request does not necessarily free a "slot" for

# a queued one (the rate might still be too high).

#

# You want to set this high enough that each attempt will process multiple entries in the queue,

# but not delay requests too much. A few milliseconds is probably a happy medium.

#

# Only used by RateLimitingRequestThrottler.

// drain-interval = 10 milliseconds

}

# A session-wide component that listens for node state changes. If it is not qualified, the driver

# assumes that it resides in the package com.datastax.oss.driver.internal.core.metadata.

#

# The driver provides a single no-op implementation out of the box: NoopNodeStateListener.

#

# You can also specify a custom class that implements NodeStateListener and has a public

# constructor with a DriverContext argument.

#

# Alternatively, you can pass an instance of your listener programmatically with

# CqlSession.builder().withNodeStateListener(). In that case, this option will be ignored.

#

# Required: unless a listener has been provided programmatically

# Modifiable at runtime: no (but custom implementations may elect to watch configuration changes

# and allow child options to be changed at runtime).

# Overridable in a profile: no

advanced.node-state-listener.class = NoopNodeStateListener

# A session-wide component that listens for node state changes. If it is not qualified, the driver

# assumes that it resides in the package com.datastax.oss.driver.internal.core.metadata.schema.

#

# The driver provides a single no-op implementation out of the box: NoopSchemaChangeListener.

#

# You can also specify a custom class that implements SchemaChangeListener and has a public

# constructor with a DriverContext argument.

#

# Alternatively, you can pass an instance of your listener programmatically with

# CqlSession.builder().withSchemaChangeListener(). In that case, this option will be ignored.

#

# Required: unless a listener has been provided programmatically

# Modifiable at runtime: no (but custom implementations may elect to watch configuration changes

# and allow child options to be changed at runtime).

# Overridable in a profile: no

advanced.schema-change-listener.class = NoopSchemaChangeListener

# The address translator to use to convert the addresses sent by Cassandra nodes into ones that

# the driver uses to connect.

# This is only needed if the nodes are not directly reachable from the driver (for example, the

# driver is in a different network region and needs to use a public IP, or it connects through a

# proxy).

#

# Required: yes

# Modifiable at runtime: no

# Overridable in a profile: no

advanced.address-translator {

# The class of the translator. If it is not qualified, the driver assumes that it resides in

# the package com.datastax.oss.driver.internal.core.addresstranslation.

#

# The driver provides the following implementations out of the box:

# - PassThroughAddressTranslator: returns all addresses unchanged

#

# You can also specify a custom class that implements AddressTranslator and has a public

# constructor with a DriverContext argument.

class = PassThroughAddressTranslator

}

advanced.protocol {

# The native protocol version to use.

#

# If this option is absent, the driver looks up the versions of the nodes at startup (by default

# in system.peers.release_version), and chooses the highest common protocol version.

# For example, if you have a mixed cluster with Apache Cassandra 2.1 nodes (protocol v3) and

# Apache Cassandra 3.0 nodes (protocol v3 and v4), then protocol v3 is chosen. If the nodes

# don't have a common protocol version, initialization fails.

#

# If this option is set, then the given version will be used for all connections, without any

# negotiation or downgrading. If any of the contact points doesn't support it, that contact

# point will be skipped.

#

# Once the protocol version is set, it can't change for the rest of the driver's lifetime; if

# an incompatible node joins the cluster later, connection will fail and the driver will force

# it down (i.e. never try to connect to it again).

#

# You can check the actual version at runtime with Cluster.getContext().protocolVersion().

#

# Required: no

# Modifiable at runtime: no

# Overridable in a profile: no

// version = V4

# The name of the algorithm used to compress protocol frames.

#

# The possible values are:

# - lz4: requires net.jpountz.lz4:lz4 in the classpath.

# - snappy: requires org.xerial.snappy:snappy-java in the classpath.

#

# The driver depends on the compression libraries, but they are optional. Make sure you

# redeclare an explicit dependency in your project. Refer to the driver's POM or manual for the

# exact version.

#

# Required: no. If the option is absent, protocol frames are not compressed.

# Modifiable at runtime: no

# Overridable in a profile: no

// compression = lz4

# The maximum length of the frames supported by the driver. Beyond that limit, requests will

# fail with an exception

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for connections created after the

# change.

# Overridable in a profile: no

max-frame-length = 256 MB

}

advanced.request {

# Whether a warning is logged when a request (such as a CQL `USE ...`) changes the active

# keyspace.

# Switching keyspace at runtime is highly discouraged, because it is inherently unsafe (other

# requests expecting the old keyspace might be running concurrently), and may cause statements

# prepared before the change to fail.

# It should only be done in very specific use cases where there is only a single client thread

# executing synchronous queries (such as a cqlsh-like interpreter). In other cases, clients

# should prefix table names in their queries instead.

#

# Note that CASSANDRA-10145 (scheduled for C* 4.0) will introduce a per-request keyspace option

# as a workaround to this issue.

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for keyspace switches occurring after

# the change.

# Overridable in a profile: no

warn-if-set-keyspace = true

# If tracing is enabled for a query, this controls how the trace is fetched.

trace {

# How many times the driver will attempt to fetch the query if it is not ready yet.

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for traces fetched after the change.

# Overridable in a profile: yes

attempts = 5

# The interval between each attempt.

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for traces fetched after the change.

# Overridable in a profile: yes

interval = 3 milliseconds

# The consistency level to use for trace queries.

# Note that the default replication strategy for the system_traces keyspace is SimpleStrategy

# with RF=2, therefore LOCAL_ONE might not work if the local DC has no replicas for a given

# trace id.

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for traces fetched after the change.

# Overridable in a profile: yes

consistency = ONE

}

}

advanced.metrics {

# The session-level metrics (all disabled by default).

#

# Required: yes

# Modifiable at runtime: no

# Overridable in a profile: no

session {

enabled = [

# The number and rate of bytes sent for the entire session (exposed as a Meter).

// bytes-sent,

# The number and rate of bytes received for the entire session (exposed as a Meter).

// bytes-received

# The number of nodes to which the driver has at least one active connection (exposed as a

# Gauge<Integer>).

// connected-nodes,

# The throughput and latency percentiles of CQL requests (exposed as a Timer).

#

# This corresponds to the overall duration of the session.execute() call, including any

# retry.

// cql-requests,

# The number of CQL requests that timed out -- that is, the session.execute() call failed

# with a DriverTimeoutException (exposed as a Counter).

// cql-client-timeouts,

# How long requests are being throttled (exposed as a Timer).

#

# This is the time between the start of the session.execute() call, and the moment when

# the throttler allows the request to proceed.

// throttling.delay,

# The size of the throttling queue (exposed as a Gauge<Integer>).

#

# This is the number of requests that the throttler is currently delaying in order to

# preserve its SLA. This metric only works with the built-in concurrency- and rate-based

# throttlers; in other cases, it will always be 0.

// throttling.queue-size,

# The number of times a request was rejected with a RequestThrottlingException (exposed as

# a Counter)

// throttling.errors,

]

# Extra configuration (for the metrics that need it)

# Required: if the 'cql-requests' metric is enabled

# Modifiable at runtime: no

# Overridable in a profile: no

cql-requests {

# The largest latency that we expect to record.

#

# This should be slightly higher than request.timeout (in theory, readings can't be higher

# than the timeout, but there might be a small overhead due to internal scheduling).

#

# This is used to scale internal data structures. If a higher recording is encountered at

# runtime, it is discarded and a warning is logged.

highest-latency = 3 seconds

# The number of significant decimal digits to which internal structures will maintain

# value resolution and separation (for example, 3 means that recordings up to 1 second

# will be recorded with a resolution of 1 millisecond or better).

#

# This must be between 0 and 5. If the value is out of range, it defaults to 3 and a

# warning is logged.

significant-digits = 3

# The interval at which percentile data is refreshed.

#

# The driver records latency data in a "live" histogram, and serves results from a cached

# snapshot. Each time the snapshot gets older than the interval, the two are switched.

# Note that this switch happens upon fetching the metrics, so if you never fetch the

# recording interval might grow higher (that shouldn't be an issue in a production

# environment because you would typically have a metrics reporter that exports to a

# monitoring tool at a regular interval).

#

# In practice, this means that if you set this to 5 minutes, you're looking at data from a

# 5-minute interval in the past, that is at most 5 minutes old. If you fetch the metrics

# at a faster pace, you will observe the same data for 5 minutes until the interval

# expires.

#

# Note that this does not apply to the total count and rates (those are updated in real

# time).

refresh-interval = 5 minutes

}

# Required: if the 'throttling.delay' metric is enabled

# Modifiable at runtime: no

# Overridable in a profile: no

throttling.delay {

highest-latency = 3 seconds

significant-digits = 3

refresh-interval = 5 minutes

}

}

# The node-level metrics (all disabled by default).

#

# Required: yes

# Modifiable at runtime: no

# Overridable in a profile: no

node {

enabled = [

# The number of connections open to this node for regular requests (exposed as a

# Gauge<Integer>).

#

# This includes the control connection (which uses at most one extra connection to a

# random node in the cluster).

// pool.open-connections,

# The number of stream ids available on the connections to this node (exposed as a

# Gauge<Integer>).

#

# Stream ids are used to multiplex requests on each connection, so this is an indication

# of how many more requests the node could handle concurrently before becoming saturated

# (note that this is a driver-side only consideration, there might be other limitations on

# the server that prevent reaching that theoretical limit).

// pool.available-streams,

# The number of requests currently executing on the connections to this node (exposed as a

# Gauge<Integer>). This includes orphaned streams.

// pool.in-flight,

# The number of "orphaned" stream ids on the connections to this node (exposed as a

# Gauge<Integer>).

#

# See the description of the connection.max-orphan-requests option for more details.

// pool.orphaned-streams,

# The number and rate of bytes sent to this node (exposed as a Meter).

// bytes-sent,

# The number and rate of bytes received from this node (exposed as a Meter).

// bytes-received,

# The throughput and latency percentiles of individual CQL messages sent to this node as

# part of an overall request (exposed as a Timer).

#

# Note that this does not necessarily correspond to the overall duration of the

# session.execute() call, since the driver might query multiple nodes because of retries

# and speculative executions. Therefore a single "request" (as seen from a client of the

# driver) can be composed of more than one of the "messages" measured by this metric.

#

# Therefore this metric is intended as an insight into the performance of this particular

# node. For statistics on overall request completion, use the session-level cql-requests.

// cql-messages,

# The number of times the driver failed to send a request to this node (exposed as a

# Counter).

#

# In those case we know the request didn't even reach the coordinator, so they are retried

# on the next node automatically (without going through the retry policy).

// errors.request.unsent,

# The number of times a request was aborted before the driver even received a response

# from this node (exposed as a Counter).

#

# This can happen in two cases: if the connection was closed due to an external event

# (such as a network error or heartbeat failure); or if there was an unexpected error

# while decoding the response (this can only be a driver bug).

// errors.request.aborted,

# The number of times this node replied with a WRITE_TIMEOUT error (exposed as a Counter).

#

# Whether this error is rethrown directly to the client, rethrown or ignored is determined

# by the RetryPolicy.

// errors.request.write-timeouts,

# The number of times this node replied with a READ_TIMEOUT error (exposed as a Counter).

#

# Whether this error is rethrown directly to the client, rethrown or ignored is determined

# by the RetryPolicy.

// errors.request.read-timeouts,

# The number of times this node replied with an UNAVAILABLE error (exposed as a Counter).

#

# Whether this error is rethrown directly to the client, rethrown or ignored is determined

# by the RetryPolicy.

// errors.request.unavailables,

# The number of times this node replied with an error that doesn't fall under other

# 'errors.*' metrics (exposed as a Counter).

// errors.request.others,

# The total number of errors on this node that caused the RetryPolicy to trigger a retry

# (exposed as a Counter).

#

# This is a sum of all the other retries.* metrics.

// retries.total,

# The number of errors on this node that caused the RetryPolicy to trigger a retry, broken

# down by error type (exposed as Counters).

// retries.aborted,

// retries.read-timeout,

// retries.write-timeout,

// retries.unavailable,

// retries.other,

# The total number of errors on this node that were ignored by the RetryPolicy (exposed as

# a Counter).

#

# This is a sum of all the other ignores.* metrics.

// ignores.total,

# The number of errors on this node that were ignored by the RetryPolicy, broken down by

# error type (exposed as Counters).

// ignores.aborted,

// ignores.read-timeout,

// ignores.write-timeout,

// ignores.unavailable,

// ignores.other,

# The number of speculative executions triggered by a slow response from this node

# (exposed as a Counter).

// speculative-executions,

# The number of errors encountered while trying to establish a connection to this node

# (exposed as a Counter).

#

# Connection errors are not a fatal issue for the driver, failed connections will be

# retried periodically according to the reconnection policy. You can choose whether or not

# to log those errors at WARN level with the connection.warn-on-init-error option.

#

# Authentication errors are not included in this counter, they are tracked separately in

# errors.connection.auth.

// errors.connection.init,

# The number of authentication errors encountered while trying to establish a connection

# to this node (exposed as a Counter).

# Authentication errors are also logged at WARN level.

// errors.connection.auth,

]

# See cql-requests in the `session` section

#

# Required: if the 'cql-messages' metric is enabled

# Modifiable at runtime: no

# Overridable in a profile: no

cql-messages {

highest-latency = 3 seconds

significant-digits = 3

refresh-interval = 5 minutes

}

}

}

advanced.socket {

# Whether or not to disable the Nagle algorithm.

#

# By default, this option is set to true (Nagle disabled), because the driver has its own

# internal message coalescing algorithm.

#

# See java.net.StandardSocketOptions.TCP_NODELAY.

#

# Required: yes

# Modifiable at runtime: yes, the new value will be used for connections created after the

# change.

# Overridable in a profile: no

tcp-no-delay = true

# All other socket options are unset by default. The actual value depends on the underlying

# Netty transport:

# - NIO uses the defaults from java.net.Socket (refer to the javadocs of

# java.net.StandardSocketOptions for each option).