IBM Support

IC65324: WMQ 7.0.1 - CONSUMERS DOES NOT RECEIVE FURTHER MESSAGES ON AUTO RECONNECT AFTER ENDING QUEUE MANAGER WITH "ENDMQM -R"

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APAR status

  • Closed as program error.

Error description

  • A Publisher application is publishing messages to a topic and
    a Subscriber application is receiving them.
    Both applications use the new auto-reconnect features introduced
    in MQ 7.0.1.
    After the queue manager is ended with "endmqm -r" the publisher
    application is able to reconnect and continues to publish
    messages.
    However, the Subscriber application is not receiving messages
    anymore. This application does not receive any warnings or
    errors or reason codes from the MQ client code.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects users of the WebSphere MQ classes for Java
    Message Service (JMS) (either point to point or
    Publish/Subscribe) using the "Auto Reconnect" feature introduced
    with WMQ 7.0.1.0
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows) +Java
    ****************************************************************
    PROBLEM SUMMARY:
    When the connectivity between the consumer application and the
    queue manager is lost (either the queue manager is shut down, or
    the network cable pulled or if there is any network error) upon
    detection of the problem, the consumer application tries to
    reconnect to the second queue manager specified on the
    connection namelist field.
    The reconnect threads that are responsible for auto-reconnect
    get into a hung state waiting for notification from other worker
    threads.
    The worker threads are in turn waiting for the reconnect threads
    for further notification causing a dead-lock situation. At this
    point, the consumer application continues to be in hung state
    not reconnecting to the secondary queue manager and not
    receiving any further messages.
    

Problem conclusion

  • When connectivity is lost between the Queue Manager and the
    consumer application, internally there are remote reconnect
    threads that are responsible for reconnecting to the secondary
    queue manager. At this stage there are several dependencies
    between the worker threads, remote dispatch threads and
    reconnect threads each waiting for notification from each other
    causing a dead-lock situation. All these threads are in
    indefinite wait state causing the consumer application not to
    reconnect to the second queue manager and receive any further
    messages.
    
    
    This thread contention and dead-lock issue between the worker
    threads and reconnect threads was removed to ensuring the
    threads are not locking each other.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v7.0
    Platform           Fix Pack 7.0.1.3
    --------           --------------------
    Windows            U200320
    AIX                U834987
    HP-UX (PA-RISC)    U834414
    HP-UX (Itanium)    U834413
    Solaris (SPARC)    U834986
    Solaris (x86-64)   U834210
    iSeries            tbc_p700_0_1_3
    Linux (x86)        U834415
    Linux (x86-64)     U834985
    Linux (zSeries)    U834412
    Linux (Power)      U835662
    
    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

    IC65324

  • Reported component name

    WMQ WINDOWS V7

  • Reported component ID

    5724H7220

  • Reported release

    701

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2009-12-24

  • Closed date

    2010-05-07

  • Last modified date

    2010-05-07

  • 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

  • R701 PSY

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Document Information

Modified date:
07 May 2010