PM75468: ABEND5C6 00C51053 CSQEOPEN OFFSETS +1FA2 +1C92 ABEND5C6 00C51024 CSQECLOS +1B62 ABEND5C6 00C510AD CSQEOCRQ +0B1A

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Attempts to open a shared queue are delayed due to system
  performance problems. By the time control is returned to the
  QMGR attempting to open the queue, the queue has been deleted
  and re-defined on a different QMGR in the QSG. The original QMGR
  accesses the list header in the CF structure for the queue and
  finds it reused due to the new instance of the queue however the
  create time does not match the DB2 record - indicating that this
  is a different queue instance. Retry logic then calls
  DB2 in order to re-read the queue definition (which obtains the
  definition for the new queue instance). After additional delays
  (before control is returned to the QMGR task) the queue is again
  deleted and re-defined by another QMGR. When the CF list header
  entry is checked this time, again it does not match. Given that
  this has now failed twice WebSphere MQ assumes something is
  wrong with the queue definition and thus abends with ABEND5C6
  00C51053.
  This apar is taken in order to determine if these abends could
  be avoided given the underlying system performance issue that
  precipitated the abends.
  
  LEVEL 2 VERIFICATION STEPS :
  Abend was seen due to a failed match between the value for
  eRQE_OpenClose_SQ_Name and mqsh.csQName as executed at
  offset +1B56 where ERQE_OPENCLOSE_SQ_NAME contains the name
  of the queue that is deleted and re-instantiated.
  

Local fix

• CORRECT UNDERLYING SYSTEM PERFORMANCE CONCERN
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of WebSphere MQ Version 7          *
  *                 Release 1 Modification 0.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Abend 5C6-00C51053 and message CSQE137E *
  *                      are generated when a shared queue is    *
  *                      opened for the first time on this queue *
  *                      manager, after the queue is recreated.  *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  This problem can occur, in a queue manager that is member of a
  QSG, when a shared queue has been recreated (deleted the defined
  again) several times.
  
  Depending on the timing of the open, this can happen when the
  shared queue is opened for first time after the recreation of
  the queue in another queue manager within the same QSG. This
  will cause an abend 5C6-00C51053 in CSQEOPEN
  (CSQE_Unexpected_ListHeader_ReUse) and the message CSQE137E to
  be issued.
  

Problem conclusion

• In this situation, CSQEOPEN has been updated to re-read shared
  queue data from DB2 and CF structure rather than abend.
  100Y
  CSQEOPEN
  

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:

  UK90221

Modules/Macros

• CSQEOPEN
  

Fix information

• Fixed component name

  WMQ Z/OS V7

• Fixed component ID

  5655R3600

Applicable component levels

• R100 PSY UK90221

     UP13/01/16 P F301

Fix is available

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