IBM Support

IV20518: PERFORMANCE DEGRADATION WHEN MANY WMQ-JMS QUEUERECEIVERS ARE CLOSED CONCURRENTLY WHEN CREATED FROM THE SAME JMS CONNECTION

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APAR status

  • Closed as new function.

Error description

  • An application creates a single JMS Connection, from which many
    JMS Sessions are created.  Each Session completes work using
    their own threads, such that the Sessions are running
    concurrently.
    
    Each thread creates a JMS QueueReceiver using the thread's
    associated Session, consumes a message from a WebSphere MQ
    queue and then closes the QueueReceiver.
    
    When numerous threads (for example 40) are repeatedly doing
    this in rapid succession, a slowdown in the queue manager is
    observed, which is observed in the JMS application as a slow
    down in the completion of the JMS method call:
    
    QueueReceiver.close();
    
    In severe cases, this method call might take several seconds to
    complete.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users of WebSphere MQ v7 classes for JMS, who are using an
    application which is making concurrent use of many JMS Sessions
    which have been created from the same JMS Connection object.
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows) +Java +Java zOS
    ****************************************************************
    PROBLEM SUMMARY:
    When a MessageConsumer is closed, due to the asynchronous
    communication design of the WebSphere MQ v7 classes for JMS,
    a communication flow is made to the queue manager to release
    any outstanding MQGET operations.
    
    The queue manager is not optimised to process many of these
    requests when being submitted concurrently.  The effect of this
    is that the queue manager can take a significant amount of
    time to process these requests when the load on the queue
    manager is high.
    

Problem conclusion

  • The WebSphere MQ classes for JMS have been optimised to reduce
    this unnecessary communication with the queue manager.  For
    example, the request to release any waiting MQGET operations
    is now only made when there are outstanding requests being made
    on the application's JMS Session.
    
    In JMS terminology, this means that in the scenario where there
    are no MessageConsumers currently performing a receive() method
    call, the closing of the MessageConsumer will not involve the
    communication flow to the queue manager.
    
    This change affects connections which are made to the queue
    manager using both the BINDINGS or CLIENT transport type.
    
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v7.0
    Platform           Fix Pack 7.0.1.10
    --------           --------------------
    Windows            U200352
    AIX                U853055
    HP-UX (PA-RISC)    U853082
    HP-UX (Itanium)    U853087
    Solaris (SPARC)    U853083
    Solaris (x86-64)   U853089
    iSeries            7.0.1.10
    Linux (x86)        U853084
    Linux (x86-64)     U853088
    Linux (zSeries)    U853085
    Linux (Power)      U853086
    zOS                7.0.1.10
    
                       v7.1
    Platform           Fix Pack 7.1.0.2
    --------           --------------------
    Windows            U200351
    AIX                U853019
    HP-UX (Itanium)    U853052
    Solaris (SPARC)    U853048
    Solaris (x86-64)   U853054
    iSeries            7.1.0.2
    Linux (x86)        U853049
    Linux (x86-64)     U853053
    Linux (zSeries)    U853050
    Linux (Power)      U853051
    zOS                7.1.0.2
    
    Platform           v7.5
    --------           --------------------
    Multiplatforms     7.5.0.1
    
    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

    IV20518

  • Reported component name

    WMQ AIX V7

  • Reported component ID

    5724H7221

  • Reported release

    701

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-05-01

  • Closed date

    2012-08-28

  • Last modified date

    2012-11-28

  • 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 AIX V7

  • Fixed component ID

    5724H7221

Applicable component levels

  • R701 PSY

       UP

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Document Information

Modified date:
28 November 2012