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IZ94267: The endmqm command does not end the queue manager and no agent processes are seen running for this queue manager.

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APAR status

  • Closed as program error.

Error description

  • When endmqm -i <Qmgrname> is executed, the queue manager does
    not end and it hangs. Some of the queue manager processes are
    found to be still running. After killing the processes, the
    queue manager can be started and stopped successfully without
    any errors.
    
    A process listing is likely to show that no agent processes are
    running. An MQ trace can be taken and the trace for amqzxma0
    may show calls to MQ function "xcsCheckProcess" where one of
    the calls is checking for an unexpected pid, i.e. a pid of a
    process not related to this queue manager.
    
    Example of MQ trace showing a call to xcsCheckProcess checking
    whether pid 18821 is alive.
    
    17:05:14.998221    18813.1           :      --{
    xcsCheckProcess
    17:05:14.998232    18813.1           :           pid(18821)
    17:05:14.998243    18813.1           :           Data:
    0x00004985
    17:05:14.998257    18813.1           :      --}
    xcsCheckProcess rc=OK
    
    Example of a process listing showing that pid 18821 is for a
    running process that we would not expect the queue manager to
    be checking:
    
    userx   18821 18819   0   Feb 08 pts/5       0:00 -ksh
    
    This example would indicate that the endmqm is hanging due to
    the problem documented in this APAR.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users who issue endmqm may rarely encounter this problem.
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows)
    ****************************************************************
    PROBLEM SUMMARY:
    There is a window of opportunity when an agent ends, for a
    completely separate process to start running, before the queue
    manager checks the liveness of the agent pid. In that
    situation, the queue manager knows that the agent is ending,
    but believes it has yet to exit. If an endmqm (with or without
    the -i option) is issued, it will wait (hang) indefinitely
    until periodic checks on the agent pid show that pid to be for
    a non-existent process. If the "completely separate process"
    that started running continues to run, the endmqm will never
    end.
    

Problem conclusion

  • The mechanism for checking the death of an agent process has
    been revised to avoid the possibility of a hang in the case
    that an agent's pid has been reused by some other process.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v6.0
    Platform           Fix Pack 6.0.2.11
    --------           --------------------
    Windows            U200326
    AIX                U839822
    HP-UX (PA-RISC)    U840685
    HP-UX (Itanium)    U840690
    Solaris (SPARC)    U840686
    Solaris (x86-64)   U840693
    iSeries            tbc_p600_0_2_11
    Linux (x86)        U840687
    Linux (x86-64)     U840692
    Linux (zSeries)    U840688
    Linux (Power)      U840689
    Linux (s390x)      U840691
    
                       v7.0
    Platform           Fix Pack 7.0.1.6
    --------           --------------------
    Windows            U200328
    AIX                U840698
    HP-UX (PA-RISC)    U841555
    HP-UX (Itanium)    U841560
    Solaris (SPARC)    U841556
    Solaris (x86-64)   U841562
    iSeries            tbc_p700_0_1_6
    Linux (x86)        U841557
    Linux (x86-64)     U841561
    Linux (zSeries)    U841558
    Linux (Power)      U841559
    
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available, information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IZ94267

  • Reported component name

    WMQ LIN X86 V6

  • Reported component ID

    5724H7204

  • Reported release

    602

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-02-02

  • Closed date

    2011-02-21

  • Last modified date

    2011-02-21

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

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

Fix information

  • Fixed component name

    WMQ LIN X86 V6

  • Fixed component ID

    5724H7204

Applicable component levels

  • R602 PSY

       UP

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Document Information

Modified date:
21 February 2011