WAS v8.5 > Troubleshoot > Troubleshooting Messaging resources > Troubleshooting messaging

Troubleshooting performance monitoring statistics

Use this task to resolve inconsistencies between performance monitoring statistics for the enterprise bean counters MethodLevelCallCount and MessageCount when deploying message driven beans in a cluster environment. This task addresses inconsistencies in performance monitoring statistics for message driven beans in a cluster environment. Sometimes the number of messages in a trace correspond with the Performance Monitoring Infrastructure (PMI)/Tivoli Performance Viewer (TPV) output statistics but not with the log message from the message driven bean. This arises because the MethodLevelCallCount enterprise bean counter has a different meaning for message driven beans than for other beans.

In general, in terms of PMI statistics collection, and with reference to the EJB container, message delivery comprises the following steps:

  1. EJB container pre-invoke processing. This prepares the execution environment for message delivery.
  2. Removing the message from the queue and invoking the message driven bean method to process that message.
  3. EJB container post-invoke processing. This cleans up the execution environment for example, committing or rolling back the transaction started during pre-invoke processing.

If there are multiple servers or threads attempting to remove a message from the queue and deliver it to a message driven bean, at Step 2 a messaging service might discover the queue is empty and there is nothing to deliver because another server or thread has already processed the message. If this happens, the message driven bean method is not called at Step 2 and therefore the MethodLevelCallCount does not correspond to the number of times a message is delivered to the message driven bean for processing. Instead, the MethodLevelCallCount indicates the number of times message delivery is attempted: the enterprise bean counter MessageCount indicates the number of successful deliveries to a message driven bean.


Related


Troubleshooting message-driven beans
Tune messaging


Reference:

Enterprise bean counters


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