IT16872: MQ can incorrectly handle internal object reference count value during media backup

APAR status

• Closed as program error.

Error description

• A queue file might disappear from the object catalog resulting
  in a queue not being visible to
  RUNMQSC or MQ Explorer.
  An earlier set of FDCs can display a pattern similar to the
  following:
  amqzlaa0    XC027010
  xcsRequestMutexSem      STOP OK
  amqzlaa0 AO175000 aouLockQHandle          STOP OK
  amqzlaa0 AO254010 aocDeregisterQHandleUse STOP OK
  
  The problem is fully diagnosed using a temporary patch from the
  MQ L3 service team.
  The diagnostic patch shows:
  An FDC with probID AO254010 and function name
  aocDeregisterQHandleUse
  MQM Function Stack
  zlaMainThread
  zlaProcessMessage
  zlaProcessSPIRequest
  zlaSPIRecordImage
  zsqSPIRecordImage
  kpiSPIRecordImage
  apiRecordMediaImage
  aomRecordMediaImage
  aocDeregisterQHandleUse
  xcsFFST
  The body of the FDC shows:
  AOCDetail
  {
  Qid 3B16FF49.11F
  DiskOffset 406
  RealName queues/<QNAME>
  Flags aocOBJFLAG_ATTRS_DISK
  ModelQid 0.0
  ReuseCount 0
  ReferenceCount 18
  RefCountByType[0] 14
  RefCountByType[1] 1
  RefCountByType[2] 0
  RefCountByType[3] 0
  RefCountByType[4] 2
  RefCountByType[5] 0
  RefCountByType[6] 0
  RefCountByType[7] 0
  RefCountByType[8] 0
  RefCountByType[9] 0
  RefCountByType[10] 0
  RefCountByType[11] 0
  RefCountByType[12] 1
  RefCountByType[13] 0
  RefCountByType[14] 0
  RefCountByType[15] 0
  QState         0X2
  BestBeforeTime 0
  IdleCount 0
  EmptyCount 0
  UseCountOC 2441754
  UseCountQL 2441753
  LogReserve 0
  RecoveryFlags: None
  {
  Qid          : 3b16ff49.ffffffff
  hsmbQHandle  : 2.11.11.5904000
  } Synonym
  {
  Qid          : 3b16ff49.11f
  hsmbQHandle  : 2.11.11.5904000
  } SynonymO
  }
  
  The important values in the output are ReferenceCount and
  RefCountByType.
  The RefCountByType array has been added as part of the
  diagnostic.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users of IBM MQ V8.0 and later.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  The IBM MQ administration utility rcdmqimg had the potential to
  incorrectly set an internal reference count for a queue. This
  caused a problem at a later time with the queue being
  incorrectly marked as deleted.
  

Problem conclusion

• The IBM MQ functions which handle rcdmqimg have been modified to
  correctly handle the internal reference count.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.6
  v9.0 CD    9.0.1
  v9.0 LTS   9.0.0.1
  
  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