IBM BPM, V8.0.1, All platforms > Tuning > Advanced tuning > Tuning for maximum concurrency
Configure JMS and JMS queue connection factories
Multiple concurrently running threads can cause a bottleneck on resources such as JMS and database connection pools if these resources are not tuned properly. The maximum connections pool size specifies the maximum number of physical connections that can be created in this pool, to the backend resource; for example a DB2 for z/OS database.
When the thread pool limit is reached, no new physical connections can be created and the requester waits until a physical connection that is currently in use is returned to the pool, or a ConnectionWaitTimeout exception is issued.
For example, if the maximum 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. The threads waiting for connections to underlying resource are blocked until the connections are freed up and allocated to them by the pool manager. If no connection is freed in the specified interval, a ConnectionWaitTimeout exception is issued.
If the maximum connections value is set to 0, the connection pool is allowed to grow infinitely. This also has the side effect of causing the connection timeout value to be ignored.
The general guideline for tuning connection factories is that their maximum connection pool size needs to match the number of concurrent threads multiplied by the number of simultaneous connections per thread.
For each JMS, MQ, or MQJMS Import, there is a Connection Factory created during application deployment (for example SAPSAPAdpt.JMSImport_CF in ContactManager). The maximum connections property of the JMS Connection Factory's connection pool must be large enough to provide connections for all threads concurrently executing in the import component. The default value is 10.
From the Connection Factory administration panel, click Additional Properties > Connection pool properties. Set the value of the Maximum connections property to the maximum size of the connection pool.