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IT03414: MQ V 7.5 AMQRMPPA CPU 100% CONSUMPTION

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • You have XA clients which call xa_open and xa_close in a loop,
    incrementing their rmid each time.
    
    When these clients are running against an MQ server, you see
    amqrmppa using 100% CPU and an increasing amount of RAM. A
    closer look at the trace shows that we are actually being held
    up by the processing being done in zswSaveRmid
    

Local fix

  • n/a
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users of XA may be affected by this problem
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    A function iterates over a linked list of structures, one of
    which is created for each different rmid that we encounter.
    
    Every time that the TM calls xa_open(), it is passing in a new
    rmid. This is potentially causing the queue manager to have to
    iterate over a very long linked list of structures, and it is
    this which is causing the high CPU usage.
    

Problem conclusion

  • The change will cause MQ to release any memory allocated on an
    xa_open(), when xa_close() is called. Since the change prevents
    the internal linked list from getting too big, the time spent
    iterating this list should be reduced.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v7.1       7.1.0.9
    v7.5       7.5.0.5
    v8.0       8.0.0.2
    
    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

    IT03414

  • Reported component name

    WMQ BASE MULTIP

  • Reported component ID

    5724H7241

  • Reported release

    750

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2014-07-30

  • Closed date

    2014-10-21

  • Last modified date

    2017-11-21

  • 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 BASE MULTIP

  • Fixed component ID

    5724H7241

Applicable component levels

  • R750 PSY

       UP

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Document Information

Modified date:
24 September 2021