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PI74029: WMQ: EXCESSIVE STORAGE ALLOCATION AND FREE OPERATIONS FOR SVRCONN CHANNELS WITH A SHARECNV VALUE GREATER THAN ZERO

A fix is available

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APAR status

  • Closed as program error.

Error description

  • Excessive storage allocation and free operations for SVRCONN
    channels with a SHARECNV value greater than zero
    .
    Additional Symptom(s) Search Keyword(s):
    CHIN trace has many CSQXGETS calls obtaining 688 or 0x2B0 bytes
    for rstSTREAMQUEUE storage, which has an eyecatcher of RSTQ .
    .
    MQOPEN MQCLOSE performance
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 8 *
    *                 Release 0 Modification 0.                    *
    ****************************************************************
    * PROBLEM DESCRIPTION: Increased CPU usage in Chinit when      *
    *                      using SVRCONNs with SHARECNV greater    *
    *                      than zero with workload that frequently *
    *                      opens and closes queues.                *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    When a SVRCONN channel is using shared conversations and is
    frequently opening and closing queues, additional storage for
    control blocks is regularly obtained and released. While this is
    correct behavior, applications that perform a large number of
    queue open and close operations may find that the additional
    overhead of this storage management begins to have an impact on
    Chinit performance exhibiting high CPU in IGVGPVT.
    

Problem conclusion

  • Some control blocks associated with opening and closing queues
    have been moved to z/OS cellpools to improve efficiency.
    000Y
    CMQXRSTF
    CSQXJST
    

Temporary fix

Comments

APAR Information

  • APAR number

    PI74029

  • Reported component name

    WMQ Z/OS 8

  • Reported component ID

    5655W9700

  • Reported release

    000

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-12-20

  • Closed date

    2017-01-18

  • Last modified date

    2017-04-04

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

    PI73537

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

    UI44032

Modules/Macros

  • CMQXRSTF CSQXJST
    

Fix information

  • Fixed component name

    WMQ Z/OS 8

  • Fixed component ID

    5655W9700

Applicable component levels

  • R000 PSY UI44032

       UP17/03/04 P F703

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:
04 April 2017