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PM88417: MESSAGE BROKER ADDRESS SPACES HAVE A NUMBER OF THREADS STUCK IN MQCMIT PROCESSING. 13/05/17 PTF PECHANGE

A fix is available

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APAR status

  • Closed as program error.

Error description

  • For a Message Broker application, where there is more
    than one resource manager involved in the RRS transaction
    (either two MQ qmgrs or MQ and another resource manager),
    code was added by PM75418, which can result in the committing
    thread going into wait loop which will never end.
    

Local fix

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: After application of UK91874(V710) or   *
    *                      UK91873(V701), when a WebSphere Message *
    *                      Broker application attempts to perform  *
    *                      a MQCMIT for an RRS transaction to two  *
    *                      or more resource managers, the MQCMIT   *
    *                      may hang.                               *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    APAR PM75418 added additional serialization to ensure that RRS
    exits would wait until a context EB was no longer in use by
    any other tasks before being used. To accomplish this a flag is
    used to indicate whether the context EB is still in use. The
    exit waits until the EB is no longer in use before performing
    the commit, by waiting for the flag to be set.
    
    When Message Broker attempts to commit a transaction involving
    multiple resource managers, the RRS exit is driven on the same
    TCB as the MQCMIT, through the module CSQMCCMT. As such there
    is no need to wait for the EB. The checks implemented in PM75418
    did not take this case into account. This results in the exit
    waiting indefinitely for CSQMCCMT to regain control and set the
    flag again.
    

Problem conclusion

  • The wait for this flag has been altered, to only occur if the
    flag wasn't set by this TCB. This ensures that the wait will not
    occur if it was set by CSQMCCMT.
    010Y
    100Y
    CSQARIB
    CSQMCLMT
    CSQMCTXE
    CSQMCTXS
    CSQ3AAES
    CSQ3AMT3
    CSQ3RRSF
    CSQ3RRSI
    CSQ3RRSM
    CSQ3RRSR
    CSQ3RRSX
    CSQ3RRXF
    CSQ5CONN
    CSQ5MONR
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PM88417

  • Reported component name

    WMQ Z/OS V7

  • Reported component ID

    5655R3600

  • Reported release

    010

  • Status

    CLOSED PER

  • PE

    YesPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2013-05-03

  • Closed date

    2013-05-31

  • Last modified date

    2013-08-02

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

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

    UK94741 UK94742

Modules/Macros

  • CSQARIB  CSQMCLMT CSQMCTXE CSQMCTXS CSQ3AAES
    CSQ3AMT3 CSQ3RRSF CSQ3RRSI CSQ3RRSM CSQ3RRSR CSQ3RRSX CSQ3RRXF
    CSQ5CONN CSQ5MONR
    

Fix information

  • Fixed component name

    WMQ Z/OS V7

  • Fixed component ID

    5655R3600

Applicable component levels

  • R010 PSY UK94741

       UP13/07/24 P F307 «

  • R100 PSY UK94742

       UP13/07/24 P F307 «

Fix is available

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Document Information

Modified date:
02 August 2013