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IV72981: WEBSPHERE MQ 7.0.1 AMQZLAA0 PROCESS SHOWS A CONSTANT INCREASE OF MEMORY USAGE, WHEN MQ QUEUE MANAGER ACCOUNTING IS ENABLED.

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APAR status

  • Closed as program error.

Error description

  • Working with WebSphere MQ Version 7.0.1.12, the amqzlaa0 process
    shows a constant increase of memory usage, when WebSphere MQ
    queue manager accounting is enabled.
    .
    While monitoring the operating system, for example with a
    command like the below:
    ps -eo pid,pcpu,pmem,time,vsz,user,args | grep 'amqzlaa0 PID'
    .
    It shows that the memory usage (the Virtual Memory Size) for a
    single amqzlaa0 process is growing constantly. See the following
    example output:
    .
    ### All the entries below are from the same USER: mqm ###
    ### and with the same COMMAND: amqzlaa0 -m 'QMgr' -fip1 ###
    ### Column VSZ grows ... ###
    ### ps -eo pid,pcpu,pmem,time,vsz,user,args ###
    .
    Date PID %CPU %MEM TIME VSZ
    .
    2015-04-11 16:01:00: 10747958 0.0 2.0 00:04:21 675204
    2015-04-11 17:01:00: 10747958 0.0 2.0 00:04:29 694820
    2015-04-11 18:01:00: 10747958 0.0 2.0 00:04:37 714348
    2015-04-11 19:01:00: 10747958 0.0 2.0 00:04:44 734132
    2015-04-11 20:01:00: 10747958 0.0 2.0 00:04:53 754648
    2015-04-11 21:01:00: 10747958 0.0 2.0 00:04:59 774180
    2015-04-11 22:01:00: 10747958 0.0 2.0 00:05:06 793612
    2015-04-11 23:01:00: 10747958 0.0 2.0 00:05:14 813128
    2015-04-12 00:01:00: 10747958 0.0 2.0 00:05:22 832672
    .
    When accounting is disabled, like in the example below, the
    memory leak in the amqzlaa0 process disappears:
    .
    ALTER QMGR ACCTQ(OFF)
    ALTER QMGR ACCTMQI(OFF)
    

Local fix

  • If it is possible then temporarily disabling collection of
    accounting data should halt the leak.
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users with accounting enabled and where a QALIAS to a topic is
    defined for the accounting queue
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    When trying to publish an accounting message to the topic that
    is used as an alias for the accounting queue, MQ incorrectly
    allocates some memory to store message properties. This memory
    is not freed.
    

Problem conclusion

  • Some code was added to ensure that allocated memory is correctly
    freed after the accounting report message had been published.
    
    ---------------------------------------------------------------
    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
    
    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

    IV72981

  • 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

    2015-05-06

  • Closed date

    2015-06-26

  • Last modified date

    2015-06-26

  • 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:
26 June 2015