(ZOS) Messaging flow for JCA message-driven beans with IBM MQ as the messaging provider
The IBM MQ messaging provider uses the IBM MQ system as the provider. The IBM MQ messaging provider supports the JCA Resource Adapter (RA) mechanism. When we install a message-driven bean application we provide an activation specification.
The following figure illustrates the messaging flow for JCA message-driven beans that use IBM 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, WAS can drive workload management directly from the CRA.
Figure 1. IBM MQ: message-driven bean processing
Processing is as follows:
- When a message arrives at the destination, the IBM MQ RA listener receives and classifies a copy of the message.
- The IBM 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 IBM 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 IBM MQ RA listener to invoke z/OS WLM directly, bypassing the SR aggregator processing in the CR.
Subtopics
- Tune IBM MQ activation specifications for workload management on WAS for z/OS
Tune the IBM MQ activation specifications to enable effective workload management (WLM) by calculating the optimal value for the Maximum server sessions property.