IBM Support

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

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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 number

    IT12007

  • Reported component name

    WMQ BASE MULTIP

  • Reported component ID

    5724H7251

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2015-10-28

  • Closed date

    2015-12-22

  • Last modified date

    2016-01-28

  • 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

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Document Information

Modified date:
28 January 2016