(ZOS) Optimizing MDB throttle support for debugging in z/OS

We can configure the message-driven bean (MDB) throttle support so that it is optimized for debugging, for example by configuring dynamic trace support for statistics gathering and presentation.

By using the configuration options described in this task, we can collect the necessary debugging information for MDB throttle support with minimal impact on performance.

Tasks

• Trace option com.ibm.ejs.jms.listener.MessageReferenceListenerPort=all=enabled. We do not need to specify this trace option if the MDB trace option is already set.

• Configure the system property com.ibm.mdb.throttle.trace.enabled. This property can have the following values:
  • Disabled, if the property is not defined or set to 0.
  • Enabled, if the property is set to 1.

• Configure dynamic trace support for statistics gathering and presentation.

  • To enable, disable, or reset messaging statistics, use the following modify command: f <server>,mdbstats,[enable | disable | reset]. The response from the console should be:

    BBOO0211I MODIFY COMMAND MDBSTATS, [ENABLE | DISABLE | RESET] COMPLETED SUCCESSFULLY
    

    The following message appears if statistics gathering is not enabled:

    BBOO0284I  STATISTICS GATHERING NOT ENABLED FOR <string>
    

  • To display statistics, use the following modify display command: f <server>,display,work,mdb,stats. The displayed information for each listener port includes:

    NAME

    The name of the listener port for which the statistics are being displayed.

    TIME

    The amount of time, in seconds, since the statistics were enabled or reset.

    TOTAL

    Total number of message references browsed since the statistics were enabled or reset.

    IN-FLIGHT

    The current number of in-flight work requests.

    EXCS

    The number of exceptions while queuing the requests.

    BLOCKS

    The total number of instances for which the throttle restricts queuing of work requests.

Related:

(ZOS) Message-driven beans and tuning settings on z/OS

Throttling inbound message flow for JCA 1.5 message-driven beans

(ZOS) Tune message-driven bean processing on z/OS using IBM MQ as the messaging provider in ASF mode

Troubleshoot message-driven beans

Troubleshoot performance monitoring statistics