Use this page to configure connection pool settings.
For example, click . The path for JMS queue connection factories is: .
Specifies the interval, in seconds, after which a connection request times out and a ConnectionWaitTimeoutException is thrown.
This value indicates the number of seconds a request for a connection waits when there are no connections available in the free pool and no new connections can be created, usually because the maximum value of connections in the particular connection pool has been reached. For example, if Connection Timeout is set to 300, and the maximum number of connections are all in use, the pool manager waits for 300 seconds for a physical connection to become available. If a physical connection is not available within this time, the pool manager initiates a ConnectionWaitTimeout exception. It usually does not make sense to retry the getConnection() method; if a longer wait time is required you should increase the Connection Timeout setting value. If a ConnectionWaitTimeout exception is caught by the application, the administrator should review the expected connection pool usage of the application and tune the connection pool and database accordingly.
If the Connection Timeout is set to 0, the pool manager waits as long as necessary until a connection becomes available. This happens when the application completes a transaction and returns a connection to the pool, or when the number of connections falls below the value of Maximum Connections, allowing a new physical connection to be created.
If Maximum 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 max int |
Specifies the maximum number of physical connections that you can create in this pool.
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.
For multiple standalone application servers
that use the same data source configuration, or J2C connection factory
configuration, a separate physical connection pool exists for each
server. If you clone these same application servers, WebSphere Application
Server implements a separate connection pool for each clone.
Consider the number of servants that access the
same resource; at runtime, this number essentially multiplies your
Maximum Connections setting. When servants invoke the same JDBC data
source or J2C connection factory configuration, WebSphere Application
Server implements a corresponding physical connection pool for every
servant. Therefore the same connection pool exists, independently,
in each servant. Your Maximum Connections setting applies to each
one of these pools.
All of these connection pools correspond
to the same data source or connection factory configuration. Therefore
all of these connection pools can potentially request connections
from the same backend resource, at the same time. The single Maximum
Connections value that you set on this console panel applies to every
one of these connection pools. Consequently, setting a high Maximum
Connections value can result in a load of connection requests that
overwhelms your backend resource.
Potentially, every application that requires the
data source or connection factory in these servants can attempt to
use the resource simultaneously. Therefore the corresponding connection
pools require connections from the same backend, at the same time.
Do not set a Maximum Connections value that might cause the load of
connection requests to overwhelm your database or other enterprise
information system (EIS).
Data type | Integer |
Default | 10 |
Range | 0 to maximum integer If Max Connections is set to 0, the Connection Timeout value is ignored. |
You can use the Tivoli Performance Viewer to find the optimal number of connections in a pool. If the number of concurrent waiters is greater than 0, but the CPU load is not close to 100%, consider increasing the connection pool size. If the Percent Used value is consistently low under normal workload, consider decreasing the number of connections in the pool.
Specifies the minimum number of physical connections to maintain.
If the size of the connection pool is at or below the minimum connection pool size, the Unused Timeout thread does not discard physical connections. However, the pool does not create connections solely to ensure that the minimum connection pool size is maintained. Also, if you set a value for Aged Timeout, connections with an expired age are discarded, regardless of the minimum pool size setting.
For example, if the Minimum 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 Minimum Connections setting.
Data type | Integer |
Default | 1 |
Range | 0 to max int |
Specifies the interval, in seconds, between runs of the pool maintenance thread.
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 Minimum 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 max int |
Specifies the interval in seconds after which an unused or idle connection is discarded.
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 exceeds the Minimum 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.
The accuracy and performance of this timeout are affected by the Reap Time value. See Reap Time for more information.
Data type | Integer |
Units | Seconds |
Default | 1800 |
Range | 0 to max int |
Specifies the interval in seconds before a physical connection is discarded.
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, the application server will not discard the connection until after the transaction is completed and the connection is closed.
The accuracy and performance of this timeout are affected by the Reap Time value. See Reap Time for more information.
Data type | Integer |
Units | Seconds |
Default | 0 |
Range | 0 to max int |
Specifies how to purge connections when a stale connection or fatal connection error is detected.
Valid values are EntirePool and FailingConnectionOnly.
Data type | String |
Defaults |
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Range |
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