Apache Geode Native C++ CHANGELOG

Pool Configuration Example and Settings

Connection pools require a standard client/server distributed system and cache configuration settings. You must also configure settings for the locator, server, and pool elements.

Locator. Host and port where a server locator is listening.
Server. Host and port where a server is listening.
Pool. Client/server connection pool.

This page shows examples of creating a pool configuration programmatically using C++ code, and declaratively using XML.

Programmatic Pool Configuration

This example shows a programmatic pool configuration. For a list of the attributes you can configure, see PoolFactory in the API docs.

cache.getPoolManager()
      .createFactory()
      .addLocator("localhost", 34756)
      .setFreeConnectionTimeout(std::chrono::milliseconds(12345))
      .setLoadConditioningInterval(std::chrono::milliseconds(23456))
      .setMaxConnections(7)
      .setMinConnections(3)
      .setPingInterval(std::chrono::milliseconds(12345))
      .setReadTimeout(std::chrono::milliseconds(23456))
      .setRetryAttempts(3)
      .setServerGroup("ServerGroup1")
      .setSocketBufferSize(32768)
      .setStatisticInterval(std::chrono::milliseconds(10123))
      .setSubscriptionAckInterval(std::chrono::milliseconds(567))
      .setSubscriptionEnabled(true)
      .setSubscriptionMessageTrackingTimeout(std::chrono::milliseconds(900123))
      .setSubscriptionRedundancy(0)
      .setThreadLocalConnections(true)
      .create("test_pool_1");

Declarative Pool Configuration

This example shows a declarative pool configuration. Following the example is a table that describes the XML pool attributes you can configure.

Note: You create an instance of PoolFactory through PoolManager.

<pool free-connection-timeout="12345" idle-timeout="5555"
      load-conditioning-interval="23456"
      max-connections="7" min-connections="3"
      name="test_pool_1" ping-interval="12345"
      read-timeout="23456" retry-attempts="3" server-group="ServerGroup1"
      socket-buffer-size="32768" statistic-interval="10123"
      subscription-ack-interval="567" subscription-enabled="true"
      subscription-message-tracking-timeout="900123"
      subscription-redundancy="0" thread-local-connections="true">
   <locator host="localhost" port="34756"/>
</pool>

Pool Attributes

Attribute Name	Description	Default
`free-connection-timeout`	Number of milliseconds (ms) that the client waits for a free connection if `max-connections` limit is configured and all connections are in use.	10000 ms
`idle-timeout`	Number of milliseconds to wait for a connection to become idle for load balancing	5000 ms
`load-conditioning-interval`	Interval in which the pool checks to see if a connection to a specific server should be moved to a different server to improve the load balance.	300000 ms (5 minutes)
`max-connections`	Maximum number of connections that the pool can create. If all connections are in use, an operation requiring a client-to server-connection is blocked until a connection is available or the `free-connection-timeout` is reached. If set to -1, there is no maximum. The setting must indicate a cap greater than `min-connections`. Note: If you use this setting to cap your pool connections, disable the pool attribute `pr-single-hop-enabled`. Leaving single hop enabled can increase thrashing and lower performance.	-1
`min-connections`	Number of connections that must be created initially.	5
`name`	Pool name.
`ping-interval`	Interval between pinging the server to show the client is alive, set in milliseconds. Pings are only sent when the `ping-interval` elapses between normal client messages. This must be set lower than the server’s `maximum-time-between-pings`.	10000 ms
`pr-single-hop-enabled`	Setting used for single-hop access to partitioned region data in the servers for some data operations. See PartitionResolver. See note in `thread-local-connections` below.	True
`read-timeout`	Number of milliseconds to wait for a response from a server before the connection times out.	10000
`retry-attempts`	Number of times to retry an operation after a time-out or exception for high availability. If set to -1, the pool tries every available server once until it succeeds or has tried all servers.	-1
`server-group`	Server group from which to select connections. If not specified, the global group of all connected servers is used.	empty
`socket-buffer-size`	Size of the socket buffer, in bytes, on each connection established.	32768
`statistic-interval`	Default frequency, in milliseconds, with which the client statistics are sent to the server. A value of `-1` indicates that the statistics are not sent to the server.	-1
`subscription-ack-interval`	Number of milliseconds to wait before sending an acknowledgment to the server about events received from the subscriptions.	100
`subscription-enabled`	Whether to establish a server to client subscription.	False
`subscription-message-tracking-timeout`	Number of milliseconds for which messages sent from a server to a client are tracked. The tracking is done to minimize duplicate events.	90000
`subscription-redundancy`	Redundancy for servers that contain subscriptions established by the client. A value of `-1` causes all available servers in the specified group to be made redundant.	0
`thread-local-connections`	Whether the connections must have affinity to the thread that last used them. Note: To set this to `true`, also set `pr-single-hop-enabled` to `false`. A `true` value in `pr-single-hop-enabled` automatically assigns a `false` value to `thread-local-connections`…	False
`update-locator-list-interval`	An integer number of milliseconds defining the interval between locator list updates. If the value is less than or equal to 0, the update will be disabled.	5000