PI37696: WMQ MASTER STORAGE DECREASING WHEN BROWSE-MARKS ARE TIMED-OUT BYCSQMMTIN AND ASSOCIATED MTMA'S ARE NOT RELEASED

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Queue Manager suffers a progressive increase of WMQ storage
  until message CSQY222E is issued. Dumps obtained shows a high
  allocation in subpool 229, Key 7,  with a high allocation in
  MTMA.
  
  GTF trace and dumps shows the cause of the problem.  It occurs
  when browse-marks are timed-out by CSQMMTIN. It releases the
  MTME storage, but not the associated MTMA(s). Note that this
  problem will only be seen when there are more than 64 threads
  getting from the queue in question (in the customer's case
  a shared queue had 80 instances of a particular client channel
  that was processing the queue).
  .
  Additional Keywords:
  SP229 KEY7
  

Local fix

• No 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: Gradual increase in storage usage when  *
  *                      >64 applications use message marking    *
  *                      (for example WSAS MDBs) when browsing a *
  *                      shared queue simultaneously.            *
  *                                                              *
  *                      Over time the accumulation of storage   *
  *                      in the MTMA phb can lead to performance *
  *                      degradation, and can cause a short on   *
  *                      storage (SOS) condition to be detected. *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When a message is marked by multiple applications using message
  marking (MQGMO_MARK_BROWSE_HANDLE/MQGMO_MARK_BROWSE_COOP), the
  MTMA array embedded within the MTME for the message is updated
  to show which handles have marked the message.
  The embedded MTMA can only record the mark for 64 handles, so
  additional MTMA control blocks are acquired and chained to the
  MTME if more than 64 handles are marking messages on the queue.
  If a marked message is removed from a shared queue by expiry
  processing, or a different queue manager in the queue sharing
  group, CSQEMTIN detects that the MTME is no longer valid and
  flags it for deletion. However when CSQMMTIN processes the
  MTME, it only frees the MTME itself, and fails to free any
  additional MTMA control blocks that were chained to it.
  

Problem conclusion

• CSQMMTIN is changed to correctly free any chained MTMA control
  blocks prior to freeing the MTME.
  010Y
  100Y
  CSQMMTIN
  

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:

  PI43317 UI28826 UI28827

Modules/Macros

• CSQMMTIN
  

Fix information

• Fixed component name

  WMQ Z/OS V7

• Fixed component ID

  5655R3600

Applicable component levels

• R010 PSY UI28826

     UP15/08/11 P F508 ¢

• R100 PSY UI28827

     UP15/08/11 P F508 ¢

Fix is available

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