IT09497: MQ EXPLORER 8.0: NOT ALL SETS OF QUEUE MANAGERS CAN BE FULLY EXPANDED AND SOME QUEUE MANAGERS ARE MISSING

APAR status

• Closed as program error.

Error description

• When using MQ Explorer 8.0 with many sets of queue managers in
  the left navigation panel, some of these sets fail to expand
  fully: some queue managers are shown, but other queue managers
  in the set are missing.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of the IBM MQ Explorer V8 who use Queue
  Manager Sets, and administer remote queue managers via an
  intermediate queue manager.
  
  
  Platforms affected:
  Windows, Linux on x86, Linux on x86-64
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When the IBM MQ Explorer starts up, a number of internal threads
  are created which look at all of the queue managers that the
  user interface has been configured to monitor, and register them
  with an internal data model. There is one internal thread for
  each queue manager that has been defined in the user interface.
  As part of the registration process, the internal threads
  associate the queue manager that they are registering with any
  Queue Manager Sets that the queue manager belongs to.
  
  While this processing was taking place, it was possible for a
  deadlock situation to occur between two internal threads which
  prevented any new queue managers from being registered with the
  IBM MQ Explorer. As a result of this, any queue managers that
  were successfully registered before the deadlock occurred would
  appear in any Queue Manager Sets that they had been assigned to.
  However, those queue managers that were still being registered
  at the time of the deadlock would not appear in any Queue
  Manager Sets.
  
  
  A Javacore taken when the deadlock occurred showed that the
  following two threads were involved:
  
  Thread 1:
  ---------------------------
  "WebSphere MQ creating : QM1"
  Blocked on: java/lang/Object@0xDCFFF8
  Owned by: "WebSphere MQ creating : QM2"
        Java callstack:
            at com/ibm/mq/explorer/core/internal/utils/
  CoreServices.sameTreeNameExists(CoreServices.java:2131)
                (entered lock:
  com/ibm/mq/explorer/core/internal/utils/CoreServices@0xD34190)
            at com/ibm/mq/explorer/core/internal/objects/
  DmQueueManager.getTreeName(DmQueueManager.java:1530(Compiled
  Code))
            at com/ibm/mq/explorer/core/internal/objects/
  DmQueueManager.(DmQueueManager.java:516)
            at com/ibm/mq/explorer/core/internal/objects/
  CreateDmQueueManager.run(CreateDmQueueManager.java:160)
                (entered lock: java/lang/Object@0x471D30)
  
  
  Thread 2:
  ---------------------------
  "WebSphere MQ creating : QM2"
  Blocked on:
  com/ibm/mq/explorer/core/internal/utils/CoreServices@0xD34190
  Owned by: "WebSphere MQ creating : QM1"
        Java callstack:
            at com/ibm/mq/explorer/core/internal/utils/
  CoreServices.getMatchingQueueManager(CoreServices.java:1625)
                (entered lock: java/lang/Object@0xDCFFF8)
            at
  com/ibm/mq/explorer/core/internal/objects/DmQueueManager.
  connectUsingVia(DmQueueManager.java:1096)
            at com/ibm/mq/explorer/core/internal/objects/
  DmQueueManager.connectToQueueManager(DmQueueManager.java:785)
            at com/ibm/mq/explorer/core/internal/objects/
  DmQueueManager.init(DmQueueManager.java:612)
            at com/ibm/mq/explorer/core/internal/objects/
  DmQueueManager.connectSynchronously(DmQueueManager.java:2289)
            at com/ibm/mq/explorer/core/internal/objects/
  CreateDmQueueManager.run(CreateDmQueueManager.java:218)
  

Problem conclusion

• The internal locking model used by the IBM MQ Explorer has been
  updated to ensure that the internal threads used to register
  queue managers with the internal data model hold all of the
  required locks before starting with the registration process.
  This ensures that the deadlock reported in the APAR no longer
  occurs.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.4
  
  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

  WMQ BASE MULTIP

• Fixed component ID

  5724H7251

Applicable component levels

• R800 PSY

     UP