[z/OS]

Messaging flow for JCA message-driven beans with WebSphere MQ as the messaging provider

The WebSphere® MQ messaging provider uses your WebSphere MQ system as the provider. The WebSphere MQ messaging provider supports the JCA Resource Adapter (RA) mechanism. When you install a message-driven bean application you provide an activation specification.

The following figure illustrates the messaging flow for JCA message-driven beans that use WebSphere MQ as the messaging provider.

The z/OS® WebSphere Application Server uses a two-part RA that supports “split” message-driven processing. The RA has a listener component which runs in the control region adjunct (CRA) and a dispatcher component which runs in each servant region (SR). The RA dispatcher component drives the application code. For some workloads, WebSphere Application Server can drive workload management directly from the CRA.

Figure 1. WebSphere MQ: message-driven bean processing
A WebSphere Application Server scalable server installation comprises a control region (CR), a control region adjunct (CRA), and several servant regions (SR). The CR contains an SR aggregator. The CRA contains a WebSphere MQ Java client, which handles messages from WebSphere MQ, and a WebSphere MQ RA listener for workload classification. Each SR contains a WebSphere MQ Java client, a WebSphere MQ RA dispatcher, and an EJB container containing a message-driven bean. The installation also has a number of WLM queues. As well as the WebSphere Application Server installation, there is a WebSphere MQ instance containing a WebSphere MQ queue where the messages originate. The text following the figure describes the path a message takes through these items.
Processing is as follows:
  1. When a message arrives at the destination, the WebSphere MQ RA listener receives and classifies a copy of the message.
  2. The WebSphere MQ RA listener invokes a control region (CR) function known as the SR aggregator.
  3. The SR aggregator uses the z/OS workload management (WLM) to pass a message token to an SR.
  4. The WebSphere MQ RA dispatcher uses the message token to receive the message and pass it to the onMessage method of the message-driven bean.

Optimization can allow the WebSphere MQ RA listener to invoke z/OS WLM directly, bypassing the SR aggregator processing in the CR.




Related concepts
Message-driven beans and tuning settings on z/OS
Related tasks
Tuning message-driven bean processing on z/OS by using WebSphere MQ as the messaging provider in ASF mode
Optimizing MDB throttle support for debugging in z/OS
Throttling inbound message flow for JCA 1.5 message-driven beans
Concept topic Concept topic    

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Last updatedLast updated: Feb 5, 2014 9:49:51 PM CST
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