IBM Support

SE38523: WMQ V7.0.1.4 OR HIGHER: AMQZXMA0 CAN TAKE LARGE AMOUNTS OF CPU WHEN STARTING THE QUEUE MANAGER VIA AN AUTOSTART JOB

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APAR status

  • Closed as program error.

Error description

  • Enduser has WebSphere MQ fixpack V7.0.1.4 or higher applied and
    a system low on system resources. When attempting to start the
    queue manager via a subsystem autostart job, the AMQZXMA0
    process may loop when trying obtain the job details of required
    WebSphere MQ proceses by repeatedly calling the QUSRJOBI api.
    .
    Additional symptoms:
    While the problem is most commonly seen with autostart jobs
    starting the queue manager (reference technote 1197928), it
    may also been seen in other environments.  Contact the Support
    Center for instructions to use the environment variable added
    by this APAR.
    .
    

Local fix

  • Remove WebSphere MQ from the autostart processing and submit the
    subsystem and queue maanger starts as separate jobs.
    

Problem summary

  • PROBLEM SUMMARY:
    ****************************************************************
    USERS AFFECTED:
    Users who are using any WMQ environment that encounters the
    resource issue on start up time will have to wait the uncommon
    length of time it takes for the system to start up in this
    scenario.
    
    Platforms affected:
    iSeries
    
    ****************************************************************
    PROBLEM SUMMARY:
    The root cause of the problem is a timing issue in an
    autostart job scenario.  The asQusrJobi is designed to perform
    a wait loop immediately after a SBMJOB, but in the autostart
    scenario this is happening in 2-4 parallel jobs.  The
    asQusrJobi is taking up CPU such that the submitted jobs that
    it is trying to get the info for have trouble getting enough
    CPU resource to start.  This scenario will keep looping, taking
    CPU resource.  Eventually (after 10-15 minutes) the jobs do get
    started.
    

Problem conclusion

  • The development team introduced a variable to increase the wait
    time of the jobs to eliminate the race condition and reduce the
    competition and interference from the other jobs.  The new wait
    time can be dynamically controlled.
    
    The problem scenario must be verified by the IBM WMQ Support
    Team and the resolution steps should be performed only under
    the direct advice and direction of the IBM WMQ Support Team.
    The use of the code change will affect the timing of the MQ
    system and when used incorrectly may have adverse effects.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v7.0
    Platform           Fix Pack 7.0.1.8
    --------           --------------------
    iSeries            7.0.1.8
    
                       v7.1
    Platform           Fix Pack 7.1.0.3
    --------           --------------------
    iSeries            7.1.0.3
    
    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

    SE38523

  • Reported component name

    WMQ ISERIES V7

  • Reported component ID

    5724H7226

  • Reported release

    701

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2011-10-18

  • Closed date

    2011-10-26

  • Last modified date

    2014-10-02

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Modules/Macros

  • RCHMGR
    

Fix information

  • Fixed component name

    WMQ ISERIES V7

  • Fixed component ID

    5724H7226

Applicable component levels

[{"Business Unit":{"code":"BU048","label":"IBM Software"},"Product":{"code":"SSCPQ63","label":"APAR \/ Maintenance"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Line of Business":{"code":"","label":""}}]

Document Information

Modified date:
27 April 2020