IBM Support

IC77278: DELAYS SEEN WHEN A CLIENT APPLICATION IS CONNECTED TO MULTIPLE QUEUE MANAGERS AND ONE OF THEM IS ENDED

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APAR status

  • Closed as program error.

Error description

  • A WebSphere MQ v7 client application has several threads, with
    each thread connecting to two queue managers. When one of the
    queue managers is ended normally, there is a large delay in
    getting messages from queues on the other queue manager.
    Other symptoms seen are
    The listener threads for those connections report reason code
    2161 - MQRC_Q_MGR_QUIESCING
    WebSphere MQ log file report AMQ9208 errors
    Error on receive from host
    Listener threads report reason codes 2009
    MQRC_CONNECTION_BROKEN
    WebSphere MQ Log files report AMQ9202 errors
    Remote host not available
    While trying to reconnect, the threads report reason code
    2059 - MQRC_Q_MGR_NOT_AVAILABLE
    and 2538 MQRC_HOST_NOT_AVAILABLE
    

Local fix

  • Restart application
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users of WebSphere MQ v7 clients where each thread connects to
    more than one queue manager.
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows)
    ****************************************************************
    PROBLEM SUMMARY:
    The problem was a delay caused by an interdependence on a
    particular lock that is held for a long time, among three
    threads.
    
    Thread 1 obtains lock A and enters a wait state
    Thread 2 obtains lock B and waits for lock A to be released
    Thread 3 waits for lock B
    
    Threads 1 and 2 are connected to the queue manager that is
    being ended while thread 3 is dealing with the other queue
    manager and hence it is indirectly held up by the wait state of
    thread 1.
    

Problem conclusion

  • The problem was fixed by modifying the code to ensure that no
    thread enters into the wait state with the lock acquired. The
    lock is released before the wait state is entered.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v7.0
    Platform           Fix Pack 7.0.1.7
    --------           --------------------
    Windows            U200333
    AIX                U843721
    HP-UX (PA-RISC)    U844089
    HP-UX (Itanium)    U844094
    Solaris (SPARC)    U844090
    Solaris (x86-64)   U844096
    iSeries            tbc_p700_0_1_7
    Linux (x86)        U844091
    Linux (x86-64)     U844095
    Linux (zSeries)    U844092
    Linux (Power)      U844093
    
    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

    IC77278

  • Reported component name

    WMQ WINDOWS V7

  • Reported component ID

    5724H7220

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-06-30

  • Closed date

    2011-09-27

  • Last modified date

    2011-09-27

  • 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 WINDOWS V7

  • Fixed component ID

    5724H7220

Applicable component levels

  • R700 PSY

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Document Information

Modified date:
27 September 2011