IT38423: MQ JMS clients fail to reconnect when using automatic client reconnection after a network break.

APAR status

• Closed as program error.

Error description

• An MQ 9.2 classes for JMS application connects to a queue
  manager and specifies the Connection Factory properties:
  
  CLIENTRECONNECTOPTIONS = ANY
  CLIENTRECONNECTTIMEOUT=1
  
  to enable automatic client reconnection. After connecting to the
  queue manager, and being disconnected, the MQ classes for JMS
  attempt to reconnect to the queue manager and time out. This
  results in a JMSException being thrown back to the application.
  After the application reconnects to the queue manager, it is
  disconnected again. However, this time the application hangs -
  the MQ classes for JMS do not reconnect to the queue manager,
  and no exception is thrown back to the application.
  
  Javacores collected when the issue occurs shows that the
  internal Remote Reconnect Thread, which is responsible for
  performing the reconnection, is stuck in a call to
  Thread.sleep(). An example of the call stack for the Remote
  Reconnect Thread when it is in this state is shown below:
  
  "JMSCCThreadPoolWorker-3" J9VMThread:0x00000000034CB500,
  omrthread_t:0x0000000012B5C390,
  java/lang/Thread:0x00000000E061A708, state:CW, prio=5
  ....
    Java callstack:
      at java/lang/Thread.sleep(Native Method)
      at java/lang/Thread.sleep(Thread.java)
      at
  com/ibm/mq/jmqi/remote/impl/RemoteReconnectThread.bestHconn(Remo
  teReconnectThread.java)
      at
  com/ibm/mq/jmqi/remote/impl/RemoteReconnectThread.run(RemoteReco
  nnectThread.java)
      at
  com/ibm/msg/client/commonservices/workqueue/WorkQueueItem.runTas
  k(WorkQueueItem.java)
      at
  com/ibm/msg/client/commonservices/workqueue/SimpleWorkQueueItem.
  runItem(SimpleWorkQueueItem.java)
      at
  com/ibm/msg/client/commonservices/workqueue/WorkQueueItem.run(Wo
  rkQueueItem.java)
      at
  com/ibm/msg/client/commonservices/workqueue/WorkQueueManager.run
  WorkQueueItem(WorkQueueManager.java)
      at
  com/ibm/msg/client/commonservices/j2se/workqueue/WorkQueueManage
  rImplementation$ThreadPoolWorker.run(WorkQueueManagerImplementat
  ion.java)
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of the MQ 9.2 classes for JMS, who have
  applications that use the automatic client reconnection
  functionality.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  The internal RemoteReconnectThread within the MQ classes for
  JMS, which was designed to handle reconnecting any broken
  connections to a queue manager, was sleeping for an extremely
  long duration of time under specific circumstances such as the
  system operating with only one connection which had been closed.
  This sleep rendered the automatic client reconnection
  functionality useless for a long period of time, meaning any new
  connections that were made are no longer being monitored to
  detect whether or not they have closed and need re-establishing.
  
  This was due to the fact that the thread was performing no
  internal checks to determine whether or not the sleep duration
  was both necessary, and thus also for a suitable duration.
  

Problem conclusion

• An extra check has been added to the internal
  RemoteReconnectThread to determine whether or not it needs to be
  sleeping at all. This means that if it does need to sleep, it
  will do so for the appropriate duration of time, as to remain
  responsive.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.2 LTS   9.2.0.5
  v9.x CD    9.2.5
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

Temporary fix

Comments

APAR Information

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

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

Fix information

• Fixed component name

  MQ BASE V9.2

• Fixed component ID

  5724H7281

Applicable component levels