IT12007: GHOST QUEUES NOT REMOVED AFTER DELETING, REDEFINING MODEL QUEUE AND RECYCLING QUEUE MANAGER AFTER ABRUPT TERMINATION.

APAR status

• Closed as program error.

Error description

• After migrating from MQ V7.5 to V8.0, user noticed many
  Temporary Dynamic Queues (TDQs) are generated by  MQ Explorer
  users.  In this case, user
  started MQ Explorer but had not yet connected to the V8 queue
  manager. However, because Autoreconnect was enabled, MQ
  Explorer was connecting and disconnecting to the new V8 qmgr
  due to the mismatch in Command Levels resulting in a large
  number of TDQs.  The customer noticed these TDQs led to large
  number of GHOST queues that could not be cleaned up by either
  deleting, recreating the MQ Explorer TDQs  or cycling the queue
  manager.
  .
  Additional symptoms:
  - ENDMQM may fail, for example with AMQ6153.
  - RCDMQIMG (or RCDMQMIMG for IBMi) may experience AMQ7047 and
    an FDC with:
     Probe Id          :- OP130012
     Component         :- AS400ReportLogTail
     Probe Description :- AMQ6125: An internal WebSphere MQ error
       has occurred.
     FDCSequenceNumber :- 0
     Arith1            :- 402 0x'192'
     Comment1          :- Checkpoint Process died !
  - STRMQM may receive FDCs for:
     AD004020 adhOpen                       arcE_OBJECT_MISSING
     AQ168001 aqpReadData                   arcE_OBJECT_MISSING
     AQ143008 aqqAccessQHeader              arcE_OBJECT_DAMAGED
  
    for Temporary Dynamic Queues (TDQs), e.g.
     Currently attached object: AMQ.5646B30D20046C02
     RealName queues/!!GHOST!797F85C3!0!EF40C4FD!16
  

Local fix

• A v8 queue manager can tolerate queue files associated with
  temporary dynamic queues being deleted while the queue manager
  is not active.
  As long as the affected queue files can be reliably identified,
  and the queue manager is stopped, these files can simply be
  deleted.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users of IBM MQ version 8 who delete a model queue and then
  abruptly terminate the queue manager before all of the temporary
  dynamic queues associated with that instance of that model queue
  have been cleaned up.
  
  
  Platforms affected:
  AIX, HP-UX Itanium, HP-UX PA-RISC, IBM iSeries, Linux on Power,
  Linux on S390, Linux on x86, Linux on x86-64, Linux on zSeries,
  Solaris SPARC, Solaris x86-64, Windows
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When an application releases a temporary dynamic queue, the
  resources associated with that queue may be kept around to be
  reused when a further TDQ is created based upon the same model
  queue.
  If a model queue is deleted then any unused resources (a.k.a
  ghost queues) associated with the current instance of that model
  are released.
  TDQs based off the deleted model that are still in use when the
  model is deleted will NOT be reused when they are eventually
  deleted.
  
  The problem arose when a TDQ created from a model still existed
  when the model was deleted, and then the queue manager was
  abruptly terminated without the TDQ first being cleaned up. In
  these circumstances the resources associated with that TDQ
  should have been deleted when the queue manager next restarts.
  This was not happening, leading to a potential accumulation of
  ghost queues.
  

Problem conclusion

• The IBM MQ V8 queue manager routines have been corrected to
  identify this condition and release the unreferenced TDQs  at
  the next queue manager restart.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.5
  
  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

  WMQ BASE MULTIP

• Fixed component ID

  5724H7251

Applicable component levels

• R800 PSY

     UP