IBM Support

IT30371: MQ might return incorrect values for accounting or statistics AverageQueueTime

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APAR status

  • Closed as program error.

Error description

  • In a system using NTP synchronization, the queue manager might
    return a large positive for AverageQueueTime.
    
    Output from amqsmon:
    
    AverageQueueTime: [174025887487825958, 0]
    Other affected attributes:
    
    TimeOnQAvg
    TimeOnQMax
    TimeOnQMin
    
    This problem likely to occur when there is a backward time shift
     in the system time because of NTP synchronization.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users using accounting and statistics will be affected by this
    problem.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    When there was a backward time shift MQ  then value calculated
    for AverageQueueTime could result in negative delta and after
    conversion to unsigned the value might become a large positive
    value. The statistics code did not correctly account for this
    possibility.
    

Problem conclusion

  • MQ accounting and statistics code has been modified to set the
    AverageQueueTime to Maximum if there is a negative time shift.
    
    The APAR IT13006 fixed similar problem for earlier releases in
    the past. The APAR added some additional changes to adjust the
    AverageQueueTime if there is a negative timeshift.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.0 LTS   9.0.0.9
    v9.1 CD    9.1.5
    v9.1 LTS   9.1.0.4
    
    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

    IT30371

  • Reported component name

    IBM MQ BASE M/P

  • Reported component ID

    5724H7261

  • Reported release

    900

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-09-24

  • Closed date

    2019-10-28

  • Last modified date

    2019-10-28

  • 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

    IBM MQ BASE M/P

  • Fixed component ID

    5724H7261

Applicable component levels

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"9.0","Edition":"","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
28 October 2019