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

A fix is available

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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 number

    PI71874

  • Reported component name

    MQ Z/OS V9

  • Reported component ID

    5655MQ900

  • Reported release

    000

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-11-07

  • Closed date

    2016-11-17

  • Last modified date

    2017-02-01

  • 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

  • Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

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Document Information

Modified date:
01 February 2017