Use this page to configure connection pool settings.
This administrative console page is common to a range of resource types; for example, JDBC data sources and JMS queue connection factories. To view this page, the path depends on the type of resource, but generally you select an instance of the resource provider, then an instance of the resource type, then click Connection Pool. For example: click Resources > JDBC Providers > JDBC_provider > Data Sources > data_source > Connection Pool.
Configuration tab
The wait is necessary when the maximum value of connections (Max Connections) to a particular connection pool is reached . For example, if Connection Timeout is set to 300 and the maximum number of connections is reached, the Pool Manager waits for 300 seconds for an available physical connection. If a physical connection is not available within this time, the Pool Manager throws a ConnectionWaitTimeoutException. It usually does not make sense to retry the getConnection() method, because if a longer wait time is required, you should set the Connection Timeout setting to a higher value. Therefore, if this exception is caught by the application, the administrator should review the expected usage of the application and tune the connection pool and the database accordingly.
If Connection Timeout is set to 0, the Pool Manager waits as long as necessary until a connection is allocated (which happens when the number of connections falls below the value of Max Connections).
If Max Connections is set to 0, which enables an infinite number of physical connections, then the Connection Timeout value is ignored.
Data type | Integer |
Units | Seconds |
Default | 180 |
Range | 0 to maximum integer |
These are the physical connections to the backend resource. Once this number is reached, no new physical connections are created and the requester waits until a physical connection that is currently in use returns to the pool, or a ConnectionWaitTimeoutException is thrown. For example: If the Max Connections value is set to 5, and there are five physical connections in use, the pool manager waits for the amount of time specified in Connection Timeout for a physical connection to become free.
Knowing the number of connection pools that can potentially request connections from the backend (such as a DB2 database or a CICS server) helps you determine a value for the Maximum Connections property.
Tip: For better performance, set the value for the connection pool lower than the value for the Max Connections option in the Web container. Lower settings, such as 10-30 connections, perform better than higher settings, such as 100.
Until this number is reached, the pool maintenance thread does not discard physical connections. However, no attempt is made to bring the number of connections up to this number. If you set a value for Aged Timeout, the minimum is not maintained. All connections with an expired age are discarded.
For example if the Min Connections value is set to 3, and one physical connection is created, the Unused Timeout thread does not discard that connection. By the same token, the thread does not automatically create two additional physical connections to reach the Min Connections setting.
Data type | Integer |
Default | 1 |
Range | 0 to maximum integer |
For example, if Reap Time is set to 60, the pool maintenance thread runs every 60 seconds. The Reap Time interval affects the accuracy of the Unused Timeout and Aged Timeout settings. The smaller the interval, the greater the accuracy. If the pool maintenance thread is enabled, set the Reap Time value less than the values of Unused Timeout and Aged Timeout. When the pool maintenance thread runs, it discards any connections remaining unused for longer than the time value specified in Unused Timeout, until it reaches the number of connections specified in Min Connections. The pool maintenance thread also discards any connections that remain active longer than the time value specified in Aged Timeout.
The Reap Time interval also affects performance. Smaller intervals mean that the pool maintenance thread runs more often and degrades performance.
To disable the pool maintenance thread set Reap Time to 0, or set both Unused Timeout and Aged Timeout to 0. The recommended way to disable the pool maintenance thread is to set Reap Time to 0, in which case Unused Timeout and Aged Timeout are ignored. However, if Unused Timeout and Aged Timeout are set to 0, the pool maintenance thread runs, but only physical connections which timeout due to non-zero timeout values are discarded.
Data type | Integer |
Units | Seconds |
Default | 180 |
Range | 0 to maximum integer |
Set the Unused Timeout value higher than the Reap Timeout value for optimal performance. Unused physical connections are only discarded if the current number of connections not in use exceeds the Min Connections setting. For example, if the unused timeout value is set to 120, and the pool maintenance thread is enabled (Reap Time is not 0), any physical connection that remains unused for two minutes is discarded. Note that accuracy of this timeout, as well as performance, is affected by the Reap Time value. See Reap Time for more information.
Data type | Integer |
Units | Seconds |
Default | 1800 |
Range | 0 to maximum integer |
Setting Aged Timeout to 0 supports active physical connections remaining in the pool indefinitely. Set the Aged Timeout value higher than the Reap Timeout value for optimal performance. For example, if the Aged Timeout value is set to 1200, and the Reap Time value is not 0, any physical connection that remains in existence for 1200 seconds (20 minutes) is discarded from the pool. The only exception is if the connection is involved in a transaction when the aged timeout is reached. If it is the connection is closed immediately after the transaction completes.
Note that accuracy of this timeout, as well as performance, are affected by the Reap Time value. See Reap Time for more information.
Data type | Integer |
Units | Seconds |
Default | 0 |
Range | 0 to maximum integer |
Valid values are EntirePool and FailingConnectionOnly.
Data type | String |
Defaults |
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Range |
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