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IV11593: Shared memory leak when messages have MQRFH2 properties.

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APAR status

  • Closed as program error.

Error description

  • Increased IPC shared memory usage may occur. If that steadily
    increases under relatively constant workload, it may be
    indicative of a leak.
    
    No errors or FDCs are generated for this problem.
    
    Note also that there may be the possibility of MQRFH2 message
    properties being incorrectly attributed to messages which do not
    have MQRFH2 properties.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users with a queue manager that processes messages containing
    message properties in MQRFH2 format may be affected by this
    problem. Shared memory leakage may occur if such messages are
    browsed and then left on a queue for long periods of time.
    
    Use of the WebSphere MQ message property functionality
    introduced in MQ V7 does not lead to this problem, since the
    message properties are not held as MQRFH2 headers.
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows)
    ****************************************************************
    PROBLEM SUMMARY:
    Message property information is created in IPC shared memory
    when a message containing MQRFH2 properties is browsed. It would
    be freed if the message were to be destructively got. If however
    the queue is unloaded (something that WebSphere MQ may do for a
    variety of reasons, including to checkpoint a queue), the
    shared memory containing the message property information may
    be leaked.
    
    As a side effect of the failure to sometimes clean up (and free)
    message property information, there is also the possibility that
    it could be picked up by some other message which does not have
    MQRFH2 properties.
    

Problem conclusion

  • The allocation and freeing of the shared memory for MQRFH2
    message properties was investigated. Changes to ensure the
    absence of memory leaks were implemented.
    
    These changes also ensure that MQRFH2 message property
    information is not left around for other, non-MQRFH2 messages to
    inadvertently pick up.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v7.0
    Platform           Fix Pack 7.0.1.8
    --------           --------------------
    Windows            U200335
    AIX                U845856
    HP-UX (PA-RISC)    U847965
    HP-UX (Itanium)    U847970
    Solaris (SPARC)    U847966
    Solaris (x86-64)   U847972
    iSeries            7.0.1.8
    Linux (x86)        U847967
    Linux (x86-64)     U847971
    Linux (zSeries)    U847968
    Linux (Power)      U847969
    
                       v7.1
    Platform           Fix Pack 7.1.0.1
    --------           --------------------
    Windows            7.1.0.1
    AIX                7.1.0.1
    HP-UX (PA-RISC)    7.1.0.1
    HP-UX (Itanium)    7.1.0.1
    Solaris (SPARC)    7.1.0.1
    Solaris (x86-64)   7.1.0.1
    iSeries            7.1.0.1
    Linux (x86)        7.1.0.1
    Linux (x86-64)     7.1.0.1
    Linux (zSeries)    7.1.0.1
    Linux (Power)      7.1.0.1
    
    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

    IV11593

  • 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

    2011-11-30

  • Closed date

    2011-12-16

  • Last modified date

    2012-01-19

  • 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

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Document Information

Modified date:
19 January 2012