PM67364: WMQ V701 ASYNCHRONOUS CONSUMER QUEUE IS NOT CORRECTLY CLEANED UP WHEN THE MDB LISTENER IS STOPPED.

APAR status

• Closed as duplicate of another APAR.

Error description

• The asynchronous consumer (which monitors the subscription's
  queue) is not correctly cleaned up when the MDB listener is
  stopped.
  .
  If the MDB listener that is started later reuses
  the same worker thread as the earlier instance,
  then messages arriving on the new subscription
  are incorrectly delivered to the old consumer.
  .
  The ServerSession pool for the old consumer was
  closed, a javax.jms.IllegalStateException was
  produced when WMQ tried to obtain a server session
  to process the message.
  .
  The following is an example that shows that the
  ServerSessionPool is attempting to use what
  has been marked as closed or closing.
  .
  [2012/06/04 11:25:40:717] 8C5E00 >
  ServerSessionPool.close c=UNK key=P8
  (13007002)
  ThreadId:00000016
  FunctionName: close
  SourceId:
    com.ibm.ejs.jms.listener.ServerSessionPool
  Category: FINER
  ExtendedMessage: Entry;
  com.ibm.ejs.jms.listener.
  WS390ServerSessionPool@b750b75
  .
  [2012/06/04
  11:38:55:947] 8CB470 >
  ServerSessionPool.getServerSession
  c=UNK key=P8 (13007002)
  ThreadId:00000031
  FunctionName: getServerSession
  SourceId:
    com.ibm.ejs.jms.listener.ServerSessionPool
  Category: FINER
  ExtendedMessage: Entry;
  com.ibm.ejs.jms.listener.
  WS390ServerSessionPool@b750b75
  .
  We can see that this connection consumer is closed
  when the MDB ends:
  .
  [2012/04/18 11:10:39:469] 8C67D0 >
  WMQConsumerShadow.close() c=UNK
  key=P8 (13007002)
  ThreadId:00000014
  FunctionName: close()
  (com.ibm.msg.client.wmq.internal.WMQConsumerShadow)
  [:/78957895]
  SourceId:
    com.ibm.msg.client.wmq.internal.WMQConsumerShadow
  Category: FINER
  ExtendedMessage: Entry; <null>
  .
  However, suddenly 18 minutes later MQ delivers a
  message to this connection consumer:
  .
  [2012/04/18 11:28:48:846] 8C2518 ?
  DUMMY.DUMMY c=UNK key=P8 (13007002)
  ThreadId:00000038
  FunctionName: DUMMY
  SourceId: DUMMY
  Category: FINEST
  ExtendedMessage: (DUMMY) [:/52e452e4]
  DUMMY: getCallbackFunction();
  com.ibm.msg.client.wmq.internal.
  WMQConnectionBrowser$WMQConnectionBrowserShadow
  @78957895
  .
  This eventually leads to the connection consumer
  attempting to get a server session from the
  closed pool:
  .
  [2012/04/18
  11:28:49:307] 8C2518 >
  ServerSessionPool.getServerSession c=UNK key=P8
  (13007002)
  ThreadId:00000038
  FunctionName: getServerSession
  SourceId:
    com.ibm.ejs.jms.listener.ServerSessionPool
  Category: FINER
  ExtendedMessage: Entry
  .
  Which throws the IllegalStateException exception.observed which
  is the root cause of the MDB failing to consume
  messages once restarted:
  
  [2012/04/18
  11:28:49:311] 8C2518 ?
  JmsMessageReferenceHandlerImpl.com.ibm.msg.
  client.jms.internal.JmsMessageReferenceHandlerImpl
  c=UNK key=P8 (13007002)
  ThreadId:00000038
  FunctionName:
  com.ibm.msg.client.jms.internal.
  JmsMessageReferenceHandlerImpl
  SourceId:
    com.ibm.msg.client.jms.internal.
    JmsMessageReferenceHandlerImpl
  Category: FINE
  ExtendedMessage:
  (com.ibm.msg.client.jms.internal.
    JmsMessageReferenceHandlerImpl)
  [:/43d043d] Tracing exception:
  javax.jms.IllegalStateException:ServerSessionPool
  closed or closing com.ibm.ejs.jms.listener.
  ServerSessionPool.getServerSession
  (ServerSessionPool.java:387)
  at com.ibm.msg.client.jms.internal.
     JmsConnectionConsumerImpl$JmsMessage
     ReferenceHandlerImpl.endDeliverInternal
     (JmsConnectionConsumerImpl.java:350)
  at com.ibm.msg.client.jms.internal.
     JmsConnectionConsumerImpl$JmsMessage
     ReferenceHandlerImpl.handleMessageReference
     (JmsConnectionConsumerImpl.java:469)
  at com.ibm.msg.client.jms.internal.
     JmsConnectionImpl$JmsProviderMessage
     RefHandler.handleMessageReference
     (JmsConnectionImpl.java:1487)
  at com.ibm.msg.client.wmq.internal.
     WMQConnectionBrowser$WMQConnectionBrowserShadow.
     consumer(WMQConnectionBrowser.java:803)
  at com.ibm.mq.jmqi.local.internal.LocalProxyConsumer.
     jmqiConsumerMethod(LocalProxyConsumer.java:207)
  

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

• Problem summary:
  An MDB Listener, running in WebSphere Application Server on
  z/OS, is configured to connect to MQ in bindings mode and
  subscribes to a topic using a non-durable subscription.
  
  After being stopped and restarted, the MDB listener subscribes
  to the topic again, but when a message is published the
  application server receives an exception and the MDB does not
  get invoked.
  
  javax.jms.IllegalStateException: ServerSessionPool closed or
  closing.
  
  The exception is caused by residual state which was not removed
  when the previous instance of the MDB listener was stopped.
  
  
  Problem resolution:
  The MQ classes for JMS have been updated to correctly remove the
  listener state when an MDB listener is stopped.
  
  This allows the MDB to be invoked correctly when the MDB
  listener is restarted.
  
  
  This fix changes the Java component of MQ, and will be
  included in a FixPack APAR.
  
  The V7.0.1 fix will be included in FixPack 7.0.1.10 (PM72574).
  The V7.1.0 fix will be included in FixPack 7.1.0.3  (PM72577).
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  PM71124

Fix information

Applicable component levels