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IZ01835: WEBSPHERE MQ PERFORMANCE IS POOR WHEN QUERYING XQMSGSA AT A TIME WHEN SYSTEM.CLUSTER.TRANSMIT.QUEUE IS DEEP.

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APAR status

  • Closed as program error.

Error description

  • If the XQMSGSA attribute of the channel status of a cluster
    sender channel is queried at a time when
    SYSTEM.CLUSTER.TRANSMIT.QUEUE is deep then the  performance of
    the queue manager as a whole can suffer considerably.
    
    
    ADDITIONAL KEYWORDS: Poor performance CLUSSDR XMITQ backed up
    backup curdepth high S.C.T.Q. InquireChannelStatus
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users with deep SYSTEM.CLUSTER.TRANSMIT.QUEUE who are inquiring
    upon the number of messages available to each individual
    cluster sender channel.
    
    Platforms affected:
     All Distributed (iSeries, all Unix and Windows)
    ****************************************************************
    PROBLEM SUMMARY:
    If the XQMSGSA(available message count for this channel)
    attribute of a cluster sender is queried then the queue
    manager has to iterate through the messages on SYSTEM.CLUSTER.
    TRANSMIT.QUEUE (SCTQ). In order to determine which messages are
    destined for this cluster sender, the queue manager needs to
    look up the full CorrelId for each message whose CorrelId hash
    value matches. If there are a lot of messages for the queried
    channel then there will be a lot of CorrelId's to look up on
    disk which can make this function very slow.
    

Problem conclusion

  • If more than 999 messages are available on
    SYSTEM.CLUSTER.TRANSMIT.QUEUE for any particular destination
    then the value 999 will be returned to any inquiry upon
    XQMSGSA for the associated channel status.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v6.0
    Platform           Fix Pack 6.0.2.3
    --------           --------------------
    Windows            U200279
    AIX                U811346
    HP-UX (PA-RISC)    U811630
    HP-UX (Itanium)    U811631
    Solaris (SPARC)    U811632
    Solaris (x86-64)   U811633
    iSeries            SI27288
    Linux (x86)        U811634
    Linux (x86-64)     U811635
    Linux (zSeries)    U811636
    Linux (Power)      U811637
    Linux (s390x)      U811638
    
    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

    IZ01835

  • Reported component name

    WMQ LIN X86 V6

  • Reported component ID

    5724H7204

  • Reported release

    600

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2007-07-24

  • Closed date

    2007-07-30

  • Last modified date

    2007-09-04

  • 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

  • R600 PSY

       UP

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Document Information

Modified date:
04 September 2007