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PI25795: WMQ Z/OS STORAGE LEAK AND FRAGMENTATION IN QMGR WHEN ATTRIBUTE CHADEXIT IS SET.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • When the QMGR has CHADEXIT set.
    CHADEXIT is the the name of the channel
    auto-definition exit.
    A storage leak in QMGR can cause a delay in
    communication between the Transaction Processing
    Facility (TPF) and WMQ on Z/OS.
    
    
    Additional Symptom(s) Search Keyword(s):
    subpool 0 key 8 SP0 KEY8 fragementation
    

Local fix

  • Recycle CHIN address space.
    

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: Increase in cpu and performance         *
    *                      degradation over time, when using a     *
    *                      channel auto definition exit with       *
    *                      cluster channels (CHADEXIT).            *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    During start up for a cluster channel, rriCallChadExit is called
    if the queue manager is configured with a channel auto
    definition exit (CHADEXIT).
    rriCallChadExit calls rriClusterFields to determine the name of
    the cluster the channel belongs to and stores the storage it
    acquires in MQCD.ClusterPtr.
    In subsequent channel start up processing rriInitExits is called
    to initialise any channel exits. This calls rriClusterFields
    again, and overwrites MQCD.ClusterPtr with the address of a
    second storage area containing the cluster name.
    When the channel terminates, the storage acquired by rriInitExit
    is freed, however the storage acquired in rriCallChadExit is
    not freed and is consequently leaked.
    Over time this results in increased storage usage by the
    channel initiator (although the leak is small - x48 bytes), and
    an increase in cpu usage and decrease in performance due to
    storage fragmentation.
    

Problem conclusion

  • rriClusterFields is updated to handle being called twice in
    channel startup processing, preventing the storage leak and
    consequent problems.
    010Y
    100Y
    CSQXREXT
    

Temporary fix

  • *********
    * HIPER *
    *********
    

Comments

  • ×**** PE15/08/03 FIX IN ERROR. SEE APAR PI37337  FOR DESCRIPTION
    ×**** PE16/02/12 FIX IN ERROR. SEE APAR PI57113  FOR DESCRIPTION
    

APAR Information

  • APAR number

    PI25795

  • Reported component name

    WMQ Z/OS V7

  • Reported component ID

    5655R3600

  • Reported release

    010

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2014-09-16

  • Closed date

    2014-10-22

  • Last modified date

    2016-04-14

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

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

    PI27234 UI22395 UI22396

Modules/Macros

  • CSQXREXT
    

Fix information

  • Fixed component name

    WMQ Z/OS V7

  • Fixed component ID

    5655R3600

Applicable component levels

  • R010 PSY UI22395

       UP14/11/13 P F411 Ž

  • R100 PSY UI22396

       UP14/11/13 P F411 Ž

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:
14 April 2016