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IV46353: WEBSPHERE MQ V7, JMS XA CLIENT CONNECTIONS WITH SHARECNV GREATER THAN 0 RESULT IN AN INCREASING NUMBER OF AMQZLAA0 PROCESSES.

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APAR status

  • Closed as program error.

Error description

  • On a WebSphere MQ server the number of amqzlaa0 processes
    increases if a channel is in use by JMS XA clients and that
    channel is defined with a SHARECNV value which is greater
    than zero.
    
    This unbounded increase in amqzlaa0 processes leads to resource
    problems reported by AMQ6026 errors
    and FDC entries:
    
    :
    Probe Id          :- XC037008
    Application Name  :- MQM
    Component         :- xcsExecProgram
    SCCS Info         :- lib/cs/unix/linux_2/amqxprmx.c,
    :
    Build Type        :- IKAP - (Production)
    Effective UserID  :- yyyy (mqm)
    Real UserID       :- yyyy (mqm)
    Program Name      :- amqzxma0
    Addressing mode   :- 64-bit
    Process           :- processid
    Process(Thread)   :- threadid
    Thread            :- 1
    ThreadingModel    :- PosixThreads
    QueueManager      :- queuemanagername
    UserApp           :- FALSE
    :
    Major Errorcode   :- xecP_E_PROC_LIMIT
    Minor Errorcode   :- OK
    Probe Type        :- MSGAMQ6026
    Probe Severity    :- 2
    Probe Description :- AMQ6026: A resource shortage prevented the
    creation of a WebSphere MQ process.
    FDCSequenceNumber :- 0
    .
    MQM Function Stack
    ExecCtrlrMain
    zxcProcessMessage
    zxcMQIRequest
    zxcConnectAgent
    zxcStartAgent
    xcsExecProgram
    xcsFFST
    :
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users of external transaction managers that co-ordinate with
    WebSphere MQ may be affected by this problem.
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows)
    ****************************************************************
    PROBLEM SUMMARY:
    If a transaction manager issued an xa_open() without issuing an
    xa_close() on a channel with SHARECNV set to something other
    than zero, then MQ was not implicitly issuing an xa_close() if
    the channel terminated unexpectedly.  This prevented threads
    inside amqzlaa0 processes from ending and therefore caused a
    resource leak.
    

Problem conclusion

  • The code was modified so that MQ would issue an implicit
    xa_close() when channels terminate unexpectedly and an xa_open()
    call had previously been issued.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v7.0       7.0.1.12
    v7.1       7.1.0.5
    v7.5       7.5.0.3
    
    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

    IV46353

  • Reported component name

    WMQ LIN X86 V7

  • Reported component ID

    5724H7224

  • Reported release

    701

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-07-31

  • Closed date

    2013-09-06

  • Last modified date

    2013-09-06

  • 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 V7

  • Fixed component ID

    5724H7224

Applicable component levels

  • R701 PSY

       UP

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Document Information

Modified date:
01 October 2021