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IC64493: OUT OF MEMORY ERROR WHEN USING THE WMQ V7 RESOURCE ADAPTER

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APAR status

  • Closed as program error.

Error description

  • An application running within an application server using the
    WebSphere MQ v7 Resource Adapter (RA) can encounter an Out
    ofMemoryError (OOM).
    
    The memory leak seen in HeapAnalyzer shows the leak as
    
    com/ibm/mq/connector/inbound/ServerSessionPoolImpl
      java/util/HashMap
        array of java/util/HashMap$Entry
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects users of the WebSphere MQ v7 RA,
    and users of the WebSphere MQ messaging provider in WebSphere
    Application Server v7.  It is most likely to be trigged by an
    uneven workload, for example when there are a number of
    message-driven beans (MDBs) processing messages concurrently
    followed by a reduction in MDB activity.
    
    Platforms affected:
     All Distributed (iSeries, all Unix and Windows) +Java
    ****************************************************************
    PROBLEM SUMMARY:
    MDB's use ServerSessions when processing messages.
    
    ServerSessions are linked to JMS Sessions by a map called the
    "server session pool". When a ServerSessions is no longer needed
    and is released, the corresponding pooled ServerSession is
    tagged as not in use.  This means that it can be removed by a
    scavenger thread that runs periodically and closes off any
    unused ServerSessions.
    
    When the scavenger thread ran it was not removing the
    ServerSessions entry in the server session pool.
    
    Each time a new ServerSession is required it gets added to the
    server session pool.  As these ServerSessions were not being
    removed by the scavenger thread a gradual memory leak is seen.
    

Problem conclusion

  • The RA has been updated so that the scavenger thread correctly
    clears out the unused ServerSessions from the server session
    pool when it runs.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v7.0
    Platform           Fix Pack 7.0.1.2
    --------           --------------------
    Windows            U200316
    AIX                U829807
    HP-UX (PA-RISC)    U829678
    HP-UX (Itanium)    U829681
    Solaris (SPARC)    U829806
    Solaris (x86-64)   U829680
    iSeries            tbc_p700_0_1_2
    Linux (x86)        U829677
    Linux (x86-64)     U829676
    Linux (zSeries)    U829682
    Linux (Power)      U829679
    
    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

    IC64493

  • 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

    2009-11-11

  • Closed date

    2009-11-27

  • Last modified date

    2009-12-08

  • 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

       UP

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Document Information

Modified date:
08 December 2009