IBM Support

IT05491: XA transaction start and transaction lookup in the Queue Manager can be slow

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APAR status

  • Closed as program error.

Error description

  • XA transactions generated by WebSphere Application Server can be
    handled slowly by the IBM MQ queue manager.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users of IBM MQ queue managers that participate in XA
    transactions managed by WebSphere Application Server.
    
    
    Platforms affected:
    AIX, HP-UX Itanium, Linux on Power, Linux on S390, Linux on x86,
    Linux on x86-64, Solaris SPARC, Linux on zSeries, Solaris
    x86-64, Windows, HP-UX PA-RISC
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    IBM MQ uses a hashing algorithm to reduce the length of lists of
    transactions within the queue manager. The algorithm was not
    adequate to deal with the XIDs generated by WebSphere
    Application Server. The hashing algorithm did not distinguish
    adequately between these XIDs, so they all appeared in the same
    list as all other WAS-originated XIDs. Lookups within this list
    became relatively slow, leading to slow queue manager
    performance for operations on transactions.
    

Problem conclusion

  • The algorithm has been changed to deal successfully with the
    XIDs generated by WebSphere Application Server, to improve the
    performance of these transactions.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v7.0       7.0.1.14
    v7.1       7.1.0.7
    v7.5       7.5.0.6
    v8.0       8.0.0.3
    
    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

    IT05491

  • Reported component name

    WMQ WINDOWS V7

  • Reported component ID

    5724H7220

  • Reported release

    701

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2014-11-11

  • Closed date

    2015-03-13

  • Last modified date

    2015-03-13

  • 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

  • R701 PSY

       UP

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Document Information

Modified date:
13 March 2015