PI53551: MQ Z/OS V8: SMF 116 CLASS(3) DATA MAY BE INCORRECT FOR CICS AND CHIN THREAD CONTROL BLOCKS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• You are finding SMF data indicating queue access for CICS
  tranids that do not access those queues. Those tranids do run
  in the same CICS regions, but they access different queue names.
  
  Other issues with validity of SMF116 data include:
  - 0 latency times (time on queue)
  - 0 pageset times and counts
  - 0 Persistent messages counts
  - 0 JWN (Journal writes)
  (when those values are expected to be non-zero)
  - application queue data saying the queue is on PSID(0) when
  you do not have application queues on PSID 0
  
  Counts appear valid at the queue level for other information
  such as  max qdepth, messages sizes, Gets/Puts....
  
  Tivoli Omegamon XE for Messaging and other monitoring tools are
  affected by this incorrect data.
  
  Additional Symptom(s) Search Keyword(s):
  WTID zero
  

Local fix

• Issue the MQ command
    RECOVER QMGR(TUNE CICSFastDealloc OFF)
  (prefix it with "/cpf" without the quotes in SDSF, where "cpf"
  is the command prefix for the queue manager).
  
  This setting will not survive a queue manager restart, so
  include the command in a member in the CSQINP2 concatenation.
  
  Setting CICSFastDealloc OFF will disable a performance
  optimization introduced in MQ V8 which comes into play when
  CICS tasks and channels start and end.
  
  Once the command has been issued it will have immediate effect.
  Issuing the following command will revert back to the V8 way of
  doing things:
    RECOVER QMGR(TUNE CICSFastDealloc ON)
  
  The following command will show the current setting:
    RECOVER QMGR(TUNE CICSFastDealloc)
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 8 *
  *                 Release 0 Modification 0.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: SMF 116 accounting records generated by *
  *                      channel initiator and/or cics tasks     *
  *                      contain incorrect values in the WTID    *
  *                      control block, leading to an incorrect  *
  *                      channel name or transaction being       *
  *                      recorded against accounting data for    *
  *                      queues.                                 *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When CICS and chinit tasks end, a QRPL_END_THREAD request is
  processed by the queue manager. While processing this request
  the WTID and WTAS control blocks are passed to the SMF writing
  task CSQ7PLRT prematurely. When the end thread request
  completes, this causes a new WTID and WTAS to be allocated to
  the task prior to the ACE representing the task being added to a
  free chain.
  When a subsequent task in the same address space starts, the ACE
  is reused, and because it already has a WTID and WTAS associated
  with it, these control blocks are also reused. However they are
  not reinitialised, and continue to incorrectly represent the
  previous task that owned the ACE control block.
  This leads to SMF data for the new task being incorrectly
  recorded as having been generated by the earlier task, which
  could have been a different channel or transaction.
  

Problem conclusion

• QRPL_END_THREAD processing is changed to pass the WTID/WTAS to
  CSQ7PLRT after all recording for the task is complete, ensuring
  that when the ACE is subsequently reused, a new WTID and WTAS
  block is allocated and initialised correctly for the new task.
  000Y
  CSQMCETH
  CSQMCPRH
  CSQ7ADAL
  CSQ7LEPL
  

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:

  UI35846

Modules/Macros

• CSQMCETH CSQMCPRH CSQ7ADAL CSQ7LEPL
  

Fix information

• Fixed component name

  WMQ Z/OS 8

• Fixed component ID

  5655W9700

Applicable component levels

• R000 PSY UI35846

     UP16/04/15 P F604

Fix is available

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