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PM63567: WMQ Z/OS: THE COMMAND SERVER HANGS. USERS ISSUING WMQ COMMANDS GET CSQO015E COMMAND ISSUED BUT NO REPLY RECEIVED.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • Error DescriptionÏ
    Users issuing WebSphere MQ commands receive
      CSQO015E : Command issued but no reply received
    STOP and START CMDSERV do not resolve the problem--a queue
    manager recycle is necessary.
    .
    In a dump, messages are built up on the
    SYSTEM.COMMAND.INPUT queue. The RTSSRV01 command server thread
    is waiting for an SSSCONN/DMCSEGAL latch.
    .
    An application has issued an MQOPEN of a dynamic shared queue.
    Because this is the first time the queue has been opened,
    CSQEOSQ invokes CSQ5STRS to allocate a list-header number in
    the structure. The request is therefore queued to the DB2SRV02
    thread. This happens while the IVSA.csObjectLatch is held.
    However, at the same time the runtime command server is
    processing a DIS Q('*') command and has switched to DB2SRV02 to
    process the shared queues. CSQM1DQU is invoked on the DB2SRV02
    thread for the dynamic shared queue and tries to get the
    IVSA.csObjectLatch. However, as the latch is held by the MQOPEN
    processing, which itself is waiting for the DB2SRV02 TCB, a
    deadly embrace has resulted.
    .
    The group command server, GRSSRV01 was able to continue
    processing commands with CMDSCOPE(*).
    

Local fix

  • Local FixÏ
    Recycle the queue manager.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 *
    *                 Release 1 Modification 0.                    *
    ****************************************************************
    * PROBLEM DESCRIPTION: Deadlock may occur when defining        *
    *                      dynamic shared queues while listing     *
    *                      defined shared queues.                  *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    When opening a dynamic shared queue at the same time as a
    "DISPLAY Q" command for shared queues is being processed, it is
    possible for one command to obtain a latch required by the other
    command. If internal DB2 server task selection then happens to
    select the same DB2 task to process both commands then a
    deadlock situation may occur.
    

Problem conclusion

  • DB2 server task selection has been amended to ensure it
    cannot select the same task for the conflicting operations.
    100Y
    CSQ5STRS
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PM63567

  • 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

    2012-04-30

  • Closed date

    2012-07-31

  • Last modified date

    2016-03-28

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

    PM57850

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

    UK80725

Modules/Macros

  • CSQ5STRS
    

Fix information

  • Fixed component name

    WMQ Z/OS V7

  • Fixed component ID

    5655R3600

Applicable component levels

  • R100 PSY UK80725

       UP12/08/16 P F208 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:
28 March 2016