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IV09144: BUSY WEBSPHERE MQ V6 CLASSES FOR JMS APPLICATIONS EXPERIENCE POOR PERFORMANCE WHEN MESSAGES ARE GREATER THAN 4KB

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APAR status

  • Closed as program error.

Error description

  • A WebSphere MQ V6 classes for JMS application experiences
    timeouts and performance slowdowns.  Traces indicate the initial
    MQGET call is made with a default buffer size of 4KB. If the
    messages on the queue are larger than 4KB, the WebSphere MQ V6
    classes for JMS resize the buffer to match the message size, and
    issues a second get with a larger buffer size.  This results in
    an increased number of MQGET calls compared with the number of
    messages received by the JMS application.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects the following users:
    
    - WebSphere MQ V6 JMS client
    - WebSphere MQ V7 classes for JMS operating in V6 migration
    mode
    - WebSphere MQ Messaging Provider in WebSphere Application
    Server 6.1, 7 and 8 operating in V6 migration mode
    
    which are consuming messages from a queue that are larger than
    4KB in size.
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows) +Java +Java zOS
    ****************************************************************
    PROBLEM SUMMARY:
    When the WebSphere MQ classes for JMS issues a message consume
    request, the initial buffer size used on the MQGET call is 4KB.
    This buffer size is increased if the message is larger than
    4KB, which results in a second MQGET call being made to the
    queue manager to fully receive the message.
    
    This larger size is used for subsequent messages for the same
    JMS MessageConsumer object. If a new MessageConsumer is
    created, the buffer size is reset back to 4KB, and two MQGET
    requests are again required to receive a message larger than
    4KB.
    
    On systems where the message sizes are typically larger than
    4KB, and JMS MessageConsumer objects are frequently created,
    this results in an increased number of get requests compared to
    the number of messages received.  This can have an impact on
    the performance of the system, and increases the load on the
    queue manager.
    

Problem conclusion

  • The WebSphere MQ classes for JMS have been updated to allow
    a property to be defined, which defines the initial buffer size
    used for MQGET requests.
    
    The property is called:
    
    com.ibm.mq.jmqi.defaultMaxMsgSize
    
    and is set as a JVM property. For example using the Java
    command line argument:
    
       -Dcom.ibm.mq.jmqi.defaultMaxMsgSize=size_in_bytes
    
    Where size_in_bytes should be replaced by a numerical value
    indicating the initial get request buffer size in bytes, for
    example:
    
       -Dcom.ibm.mq.jmqi.defaultMaxMsgSize=8192
    
    to use a default 8KB buffer.
    
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v6.0
    Platform           Fix Pack 6.0.2.12
    --------           --------------------
    Windows            U200331
    AIX                U842074
    HP-UX (PA-RISC)    U842208
    HP-UX (Itanium)    U842213
    Solaris (SPARC)    U842209
    Solaris (x86-64)   U842216
    iSeries            tbc_p600_0_2_12
    Linux (x86)        U842210
    Linux (x86-64)     U842215
    Linux (zSeries)    U842211
    Linux (Power)      U842212
    Linux (s390x)      U842214
    
                       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
    zOS                7.0.1.8
    
                       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
    zOS                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

    IV09144

  • Reported component name

    WMQ LIN X86 V6

  • Reported component ID

    5724H7204

  • Reported release

    602

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-10-18

  • Closed date

    2011-11-29

  • Last modified date

    2012-01-16

  • 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 LIN X86 V6

  • Fixed component ID

    5724H7204

Applicable component levels

  • R602 PSY

       UP

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Document Information

Modified date:
16 January 2012