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IT17773: Queue manager becomes unresponsive eventually reporting log full errors: AMQ6709 and AMQ7463

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • Queue manager hangs during MQPUT processing on behalf of an
    application putting to a remote clustered queue.
    
    Eventually the checkpointer component also hangs, and so the
    whole queue manager becomes unresponsive and the following
    errors are generated:
    
      AMQ6709: The log for the queue manager is full
      AMQ7463: The log for queue manager EMPMIB1 is full
    
    These errors are seen soonest when the queue manager is doing
    larger quantities of persistent messaging, which consumes log
    space.
    
    FDCs also appear:
    
      KN749015   kqiDeregisterCLUSSDR
      XC307100   xlsRequestMutex
    
    If at this point the user ends the queue manager, the following
    FDCs also appear:
    
      PS058054   psiStopAllTasks
      PS058099   psiStopAllTasks
      XC307030   xlsRequestMutex
      AT030050   atmLockDataMutex
      AT036010   atmRecoverTransaction
      XC308010   xlsReleaseMutex
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users of MQ where administrative changes are being made to
    remove cluster channels or switch which channel is in use for a
    cluster transmission queue, while the queue manager is trying to
    move messages over those channels.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    There existed a small timing window within the queue manager
    MQPUT operation, in which it would notice a change to the
    channel definition, and retry some of the steps.  In doing this
    the code tried to obtain a lock already held by the thread, and
    this caused a permanent hang on that thread.
    
    Before retrying, the MQ code should have released the lock.
    
    The effect was wider than the original MQPUT, because the lock
    was then never released, and eventually the checkpointer
    component of the queue manager was not able to continue with its
    work.  This led to the queue manager's log becoming full.
    

Problem conclusion

  • The MQ product code has been corrected so it will release the
    lock that ought to have been released.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v7.5       7.5.0.8
    v8.0       8.0.0.7
    v9.0 CD    9.0.2
    v9.0 LTS   9.0.0.1
    
    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

    IT17773

  • Reported component name

    WEBSPHERE MQ 7.

  • Reported component ID

    5724H7240

  • Reported release

    750

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-11-02

  • Closed date

    2017-01-06

  • Last modified date

    2017-06-01

  • 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

    WEBSPHERE MQ 7.

  • Fixed component ID

    5724H7240

Applicable component levels

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSFKSJ","label":"WebSphere MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.5","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
29 June 2020