You can configure a standard JMS trigger and its associated trigger service to process a group or “batch” of messages at one time. Batch processing can be an effective way of handling a high volume of small messages for the purposes of persisting them or delivering them to another back-end resource. For example, you might want to take a batch of messages, create a packet of SAP IDocs, and send the packet to SAP with a single call. Alternatively, you might want to insert multiple messages into a database at one time using only one insert. The trigger service processes the messages as a unit as opposed to in a series.

The Max batch messages property indicates the maximum number of messages that the trigger service can receive at one time. For example, if the Max batch messages property is set to 5, Integration Server passes the trigger service up to 5 messages received by the JMS trigger to process during a single execution.

Integration Server uses one consumer to receive and process a batch of messages. During pre-processing, Integration Server checks the maximum delivery count for each message and, if exactly-once processing is configured, determines whether or not the message is a duplicate. Integration Server then bundles the message into a single IData and passes it to the trigger service. If the message has exceeded the maximum delivery count or is a duplicate message, Integration Server does not include it in the message batch sent to the trigger service.

Integration Server acknowledges all the messages received in a batch from the JMS provider at one time. This includes messages that failed pre-processing. As described by the Java Message Service standard, when a client acknowledges one message, the client acknowledges all of the messages received by the session. Because Integration Server uses a consumer that includes a javax.jms.MessageConsumer and a javax.jms.Session, when Integration Server acknowledges one message in the batch, it effectively acknowledges all the messages received in the batch.

If a batch of messages is not acknowledged or they are recovered back to the JMS provider, the JMS provider can redeliver all of the messages in the batch to the JMS trigger. However, when using webMethods Broker, Integration Server can acknowledge individual messages that fail pre-processing.