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IT19783: IBM MQ 8.0.0.6 queue manager terminates due to lack of stack space

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APAR status

  • Closed as program error.

Error description

  • A queue manager terminated due to a lack of stack space. The
    queue manager should not have stopped automatically because of
    this lack of stack space - the intent is to catch that issue
    before it becomes a serious problem.
    
    In addition to the queue manager stopping, an FFST diagnostic
    file will be generated with the following characteristics:
    
    LVLS              :- 8.0.0.6
    Probe Id          :- KN378077
    Component         :- ksiEvalInternal
    Major Errorcode   :- krcE_RESOURCE_PROBLEM
    Minor Errorcode   :- OK
    Probe Description :- AMQ6125: An internal WebSphere MQ error has
    occurred.
    Comment1          :- Operating system stack limit reached,
    reduce selector complexity
    
    MQM Function Stack
    zlaMainThread
    zlaProcessMessage
    zlaProcessMQIRequest
    zlaMQGETM
    zsqMQGETM
    kpiMQGETM
    kqiWaitForMessage
    apiGetMessage
    aqmGetMessage
    aqhGetMessage
    aqhLocateMessage
    aqhCheckMsgChains
    ksiSqlTreeEvaluate
    ksiEval
    ksiEvalInternal
    ksiEvalInternal
    xcsFFST
    

Local fix

  • Either increase the resources available to the queue manager, or
    reduce the workload.
    
    In the original scenario where this issue was observed, the
    cause of the high stack space usage was very complex message
    selector string. In this case, reduce selector complexity to
    avoid excessive amounts of stack space being used.
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Systems running MQ version 7.1.0.8, 7.5.0.7 or 8.0.0.6 that are
    resource limited.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    When the low resource diagnostic FFST code is executed in
    combination with low resource availability, the queue manager
    stops due to lack of available system stack space (this FFST
    diagnostic should normally avoid this happening).
    
    A variation of the problem may be observed users running
    7.1.0.8 or 7.5.0.7. This manifested itself as the amqzmuc0
    process becoming unresponsive whilst it contested a lock within
    the diagnostic code, in this situation xecL_W_LONG_LOCK_WAIT
    Failure Data Capture (FDC) recordss, together with
    xecL_W_SEM_OWNER_DIED FDC records s may appear from the amqzlaa0
    process.
    

Problem conclusion

  • MQ has been modified to minimise use of stack space whilst
    executing diagnostic FFST code at version 8, and prevent the
    diagnostic lock contention at v7.
    
    An improvement to the diagnostic routines made as part of this
    change has been delivered to MQ version 9 releases, hence the
    additional targets listed below.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v7.1       7.1.0.9
    v7.5       7.5.0.8
    v8.0       8.0.0.7
    v9.0 CD    9.0.4
    v9.0 LTS   9.0.0.2
    
    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

    IT19783

  • Reported component name

    WMQ BASE MULTIP

  • Reported component ID

    5724H7251

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2017-03-23

  • Closed date

    2017-06-30

  • Last modified date

    2017-12-21

  • 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

    5724H7251

Applicable component levels

  • R800 PSY

       UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"8.0.0.0","Edition":"","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
21 December 2017