Messaging flow for JCA message-driven beans with WebSphere MQ as the messaging provider
The WebSphere MQ messaging provider uses the 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 WAS 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, WAS can drive workload management directly from the CRA.
Figure 1. WebSphere MQ: message-driven bean processing
Processing is as follows:
- When a message arrives at the destination, the WebSphere MQ
RA listener receives and classifies a copy of the message.
- The WebSphere MQ RA listener invokes a control region (CR) function known as the SR aggregator.
- The SR aggregator uses z/OS workload management (WLM) to pass a message token (not the actual message) to an SR.
- 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.
Subtopics
- (zos) Tune WebSphere MQ activation specifications for workload management on WebSphere Application Server for z/OS
Tune the WebSphere MQ activation specifications to enable effective workload management (WLM) by calculating the optimal value for the Maximum server sessions property.
Related tasks
(zos) Optimizing MDB throttle support for debugging in z/OS