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PI35954: HANG IN DB2 THREAD USING MQ WITH RRS AS SYNCPOINT COORDINATOR.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • An issue occurs when an application repeatedly calls a
    DB2 stored procedure that puts a message to MQ.  This is
    background information:
    .
    1. The customer recreated this using a distributed application,
       but for ease of doc-gathering, the customer used a batch job
       this time.  So, they started batch job BATCHPGM1.
    .
    2. Batch job BATCHPGM1 executes package PACKAGE1, which
       connects to DB2 and executes stored procedure
       STORED_PROCEDURE.
    .
    3. STORED_PROCEDURE executes package PACKAGE2, which puts a
       message to MQ series.
    .
    4. The batch job calls the stored procedure in step #3 5000
       times
    The issue with MQ support is around the fact that performing
    queue-manager abnormal termination processing, CSQVATRM, goes
    through all ASCEs looking for any threads which are in the
    middle of processing in the queue-manager (such as the backout
    exit thread mentioned above). However, CSQVATRM does not
    process the ASCE for MQ Master as ASCEACT is not set. This
    means that the thread is left suspended indefinitely following
    queue-manager termination.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 *
    *                 Release 1 Modification 0                     *
    ****************************************************************
    * PROBLEM DESCRIPTION: Following abnormal termination of a     *
    *                      queue manager any threads which were    *
    *                      acting as Server Distributed Syncpoint  *
    *                      Resource Manager SDSRM may hang         *
    *                      indefinitely.                           *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    When an address space is acting as a Server Distributed
    Syncpoint Resource Manager and a commit or abort is
    requested, a temporary dynamic ASCE is created. When a queue
    manager terminates abnormally CSQVATRM will terminate all the
    threads associated with allied ASCEs, however it overlooks
    temporary dynamic ones. If the commit or abort hadn't completed
    then the temporary dynamic ASCE will still exist and the thread
    will hang indefinitely.
    

Problem conclusion

  • CSQVATRM will now terminate EBs which are associated with
    temporary dynamic ASCEs.
    100Y
    CSQVATRM
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PI35954

  • Reported component name

    WMQ Z/OS V7

  • Reported component ID

    5655R3600

  • Reported release

    100

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2015-02-27

  • Closed date

    2015-05-05

  • Last modified date

    2017-03-14

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

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

    PI40053 UI27339 PI78136

Modules/Macros

  • CSQVATRM
    

Fix information

  • Fixed component name

    WMQ Z/OS V7

  • Fixed component ID

    5655R3600

Applicable component levels

  • R100 PSY UI27339

       UP15/06/03 P F506 ¢

Fix is available

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Document Information

Modified date:
14 March 2017