Concurrency

The Concurrency property specifies whether the message consumers use connection consumer or serialized processing. To use concurrent processing for a connection, select the Connection consumer setting. To use serial execution, select the Serial mode setting. This property applies to topic subscribers and queue receivers, and is specified in the Basic properties dialog.

You can configure JMS clients to use connection consumers to improve message throughput through concurrent processing. Connection consumers consume messages that are specified by a destination and an optional message selector. See Message Selector.

To start processing, a connection consumer gets a server session from its pool and loads the session with a message. Server sessions associate a JMS session with a thread. The server session pool is a set of server sessions provided to a connection consumer to process its messages.

The use of connection consumers increases message processing performance by enabling concurrent processing using multiple threads. You can specify the number of message driven beans (MDBs) or server session pool to assign to a JMS Collaboration to process messages concurrently. When you use connection consumer with fully concurrent or protected concurrent FIFO processing, this setting allows the integration server to assign multiple threads to execute the Collaboration on a particular message destination.

For queues, you can also use connection consumers for concurrent processing on multiple CPUs and application servers on a single system. This configuration does affect FIFO processing. For information, refer to Message Processing Order.

You specify the maximum number of threads per server session pool as described in Server Session Pool Size. By default, the maximum number of threads is 5.

The maximum number of messages that a connection consumer can load into a server session at one time is set at 1 and cannot be changed (see Server Session Batch Size).

Default Value

The default JMS client concurrency mode is Serial mode.