PI91842: MQ Z/OS V8:ABN=5C6-00E50001,LOC=CSQELPLM.CSQEWCMQ+00000712

APAR status

• Closed as unreproducible in next release.

Error description

• Customer complained that one queue manager in queue sharing
  group took following abend:
  CSQA,ABN=5C6-00E50001,U=SYSOPR  ,C=W9700.800.CFM
  -CSQEWCMQ,M=CSQGFRCV,LOC=CSQELPLM.CSQEWCMQ+00000712
  
  The abend occurred while resolving an indoubt QSG disposition
  unit of work, where the unit of work contained puts to a shared
  queue that were performed on a qmgr other than the one
  performing the resolve, and which is no longer running.
  CSQERRIN obtained a latch to serialise remote resolve
  processing, and called CSQERIND, which rebuilt the control
  blocks representing the uow operations. It then called CSQESYNC
  to commit the UOW. As part of this CSQEKATM was called to
  determine if the committed puts required any  other qmgrs to be
  notified (for example, due to triggering).
  However the IVSA pointer for the queue was not set, leading to
  these  checks being done using the contents of low core.
  Normally this results in it determining that no broadcast is
  required,  however in this instance, the values in low core
  caused CSQEWCMQ to be called to perform the notification - this
  requested the PCT latch, but as this has the same class as the
  remote resolve latch, a hierarchy violation was detected and
  the abend occurred.
  
  Additional Symptom(s) Search Keyword(s):
  

Local fix

• n/a
  

Problem summary

•  While committing an indoubt group unit of
  recovery for an inactive peer, CSQERIND calls CSQESYNC to
  commit any shared queue operations in the UR, while holding the
  remote resolve latch.
  CSQESYNC then calls CSQEKATM to check if any K&T notifications
  should be broadcast to other queue managers. However, the ivsa
  address is not available, leading to the notification being
  generated based on values in low core.
  If any notifications are generated, CSQEWCMQ is called and
  attempts to get the PCT latch. However this latch conflicts with
  the remote resolve latch already held, leading to the reported
  latch hierarchy violation abend.
  

Problem conclusion

Temporary fix

•  n/a
  

Comments

•  A fix for this error is no longer required at this
  release.
  

APAR Information

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

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

  PH08454

Fix information

• Fixed component name

  IBM MQ Z/OS V8

• Fixed component ID

  5655W9700

Applicable component levels