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PM90755: WMQ V7.0.1 - MESSAGE HANDLE IS NOT FREED WHEN AN IMS MPP PROGRAM ENDS AND AN IMPLICIT DISCONNECT TAKES PLACE.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • Message handle is not freed when an implicit disconnect takes
    place.
    
    A small PLI/PL1 program running in an IMS MPP environment,
    linked with CSQQSTUB issues the following commands:
    
    MQCONN - MQCRTMH - MQSETMP - MQSETMP - MQPUT1
    ==> no MQDLTMH nor MQDISC are issued.
    
    When the program ends an implicit disconnect takes place and
    CSQQTTHD does not call CSQBCRMH to clear the message handle.
    In case of an explicit MQDISC call, CSQQNORM calls CSQBCRMH
    to clear the message handle.
    
    This problem may lead to a memory leak in the IMS MPP region
    which is filled with message handles ( BMSGH ) and message
    properties blocks in Subpool 131 (SP131) key8.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 *
    *                 Release 0 Modification 1 and Version 7       *
    *                 Release 1 Modification 0.                    *
    ****************************************************************
    * PROBLEM DESCRIPTION: Memory leak in IMS MPP region when      *
    *                      programs running in it issue an         *
    *                      MQCRTMH, but end without a MQDISC so    *
    *                      the message handle is not freed.        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    An application program running in an IMS MPP region creates a
    message handle with a MQCRTMH and does not issue a MQDLTMH or a
    MQDISC.
    So an implicit disconnect is done when the application ends. But
    this does not cause CSQBCRMH to be be called to free the message
    handle storage - which is done by CSQQNORM when an explicit
    MQDISC is issued.
    Over time this will cause a memory leak in the IMS MPP region.
    Another potential symptom is
    CSV002I REQUESTS FOR MODULE CSQAPEPL EXCEED MAXIMUM USE COUNT
    Additional Keywords: CSQBPAPI
    

Problem conclusion

  • CSQQSSON and CSQQTTHD have been updated to call CSQBCRMH on
    an implicit disconnect to free message handle storage.
    CSQQTMID has also been updated to free the copy of CSQBCRMH
    which may be loaded by the fix.
    010Y
    100Y
    CSQQSSON
    CSQQTMID
    CSQQTTHD
    

Temporary fix

Comments

  • ×**** PE15/02/10 FIX IN ERROR. SEE APAR PI34742  FOR DESCRIPTION
    

APAR Information

  • APAR number

    PM90755

  • Reported component name

    WMQ Z/OS V7

  • Reported component ID

    5655R3600

  • Reported release

    018

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2013-06-10

  • Closed date

    2013-10-30

  • Last modified date

    2015-03-03

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

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

    UI11930 UI11931

Modules/Macros

  • CSQQSSON CSQQTMID CSQQTTHD
    

Fix information

  • Fixed component name

    WMQ Z/OS V7

  • Fixed component ID

    5655R3600

Applicable component levels

  • R010 PSY UI11930

       UP13/11/20 P F311

  • R100 PSY UI11931

       UP13/11/20 P F311

Fix is available

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Document Information

Modified date:
03 March 2015