PI71874: MQ Z/OS ISSUING DISPLAY USAGE TYPE(DATASET) CAN CAUSE INCREASE IN CPU WHEN USING LARGE PAGESETS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• It seems that both the DISPLAY USAGE TYPE(PAGESET)
  and the DISPLAY USAGE TYPE(DATASET) command will
  result in a read of every space map page in every
  page set in order to count the number of allocated
  pages, hence causing high CPU in the MSTR.
  .
  The customer reporting the issue was using Omegamon
  and using DISPLAY USAGE commands with
  DISPLAY USAGE TYPE(DATASET) being issued every 1
  minute.
  It is unnecessary for the number of allocated pages
  to be counted for a DISPLAY USAGE TYPE(DATASET)
  command.
  .
  Additional Symptom(s) Search Keyword(s):
  .
  NOTE:
  The DISPLAY USAGE TYPE(PAGESET) will read
  of every space map page in every page set
  in order to count the number of allocated
  pages, hence will cause high CPU if issued
  frequently.
  

Local fix

• Change the frequency of using the DISPLAY USAGE TYPE(DATASET)
  and DISPLAY USAGE TYPE(PAGESET)
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of IBM MQ for z/OS Version 9 Release 0             *
  * Modification 0.                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Command DISPLAY USAGE TYPE(DATASET) or TYPE(ALL) can         *
  * increase CPU usage if command is frequently invoked and      *
  * there are large extended pagesets defined.                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * N/A                                                          *
  ****************************************************************
  Command DISPLAY USAGE TYPE(DATASET) performs unnecessary
  processing with regards the collection of page set usage
  information.
  

Problem conclusion

• Command DISPLAY USAGE TYPE(DATASET) has been changed to skip the
  collection of page statistics that are not required.
  

Temporary fix

Comments

APAR Information

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

  PI68873

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

  UI42689

Modules/Macros

• CSQICUSE CSQIDUSE CSQISTA1
  

Fix information

• Fixed component name

  MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R000 PSY UI42689

     UP17/01/10 P F701

Fix is available

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