PM98668: WMQ 7.0.1 INCREASE IN MIPS DUE TO ORPHANING OF MTME CONTROL BLOCKS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The customer was experiencing an increase in MIPS which was due
  to orphaning of MTME control blocks, which can occur when there
  are multiple MDB listeners processing the same queue.
  .
  The SYSTRACE showed the following:
  00A92988  EXT   1005 077C1000 9C2A6096  00001005
              CSQMMTIN 20090729 + x'596' in CSQMLPLM
  
  00A92988  I/O  00662 077C2000 9C2A6028  6080C0C9 0A2702F0
                  00800000
              CSQMMTIN 20090729 + x'528' in CSQMLPLM
                                        00F449E0 00000000
  00A92988  EXT   1005 077C2000 9C2A6028  00001005
              CSQMMTIN 20090729 + x'528' in CSQMLPLM
  00A92988  DSP   077C2000 9C2A6028  00000000 5B1323FC 5B1323BC
              CSQMMTIN 20090729 + x'528' in CSQMLPLM
  00A92988  EXT   1005 077C2000 9C2A6028  00001005
  
              CSQMMTIN 20090729 + x'528' in CSQMLPLM
  00A92988  EXT   1005 077C0000 9C2A6880  00001005
  
              CSQMMTIN 20090729 + x'D80' in CSQMLPLM
  .
  MQTHRD out showed the following:
  *PEB 14FDA1D8 ACE 14FDA178 CCB 1BCE7D38 TCB 00A92988 RB
  00A970D8 PROG 8000
    Service Task,
    SYSTEM   212.xxxxC00
    Latch Held Mask 00000010 = (28)ASMSQL
    PSW 077C2000 9C2A6028 DSA 5B132248 (CSQMMTIN)
    5B132248 5B55A248 00016BD8
    CSQMMTIN CSQVEUS3 CSQVEUS4
  .
  
  Additional Symptom(s) Search Keyword(s):
  .
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 *
  *                 Release 0 Modification 1 and Release 1       *
  *                 Modification 0.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Increase in cpu usage and storage usage *
  *                      over time when an application uses      *
  *                      message marking and/or message          *
  *                      selection (for example, MDBs running    *
  *                      under WSAS).                            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When an application browsing a queue checks if a message has
  been marked, or if a message has already been evaluated against
  a selector, CSQMMTPR attempts to locate an MTME control block
  for the message. If no MTME exists, a new one is created for
  that message.
  It is possible for another task to delete the same message
  shortly before the check occurs, and cause any existing MTME
  to be deleted.
  When the original task performs the check, this results in a
  new MTME being created, and because the message is now deleted
  the new MTME will never be deleted.
  Over time, the number of such orphaned MTMEs can increase,
  leading to increased storage usage, and a high cpu cost when
  MTME synonym chains are searched.
  

Problem conclusion

• CSQMMTPR is changed to no longer create an MTME for a message
  when checking if that message has been marked or evaluated
  against the selector.
  010Y
  100Y
  CSQMMTPR
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  UI12025 UI12026

Modules/Macros

• CSQMMTPR
  

Fix information

• Fixed component name

  WMQ Z/OS V7

• Fixed component ID

  5655R3600

Applicable component levels

• R010 PSY UI12025

     UP13/11/20 P F311 Ž

• R100 PSY UI12026

     UP13/11/20 P F311 Ž

Fix is available

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