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IT19598: AMQ9510 reason code 2150 issued for SYSTEM.CLUSTER.COMMAND.QUEUE

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APAR status

  • Closed as program error.

Error description

  • After altering the queue manager's CCSID, the following messages
    might be issued from the clustering component of the queue
    manager.  The queue manager will eventually terminate, unless it
    is ended manually.  However, restarting the queue manager
    resolves the issue permanently.
    
    The errors relate to character data within internal MQ command
    messages used by the clustering component of the queue manager.
    
    AMQ9510: Messages cannot be retrieved from a queue.
    EXPLANATION:
    The attempt to get messages from queue
    'SYSTEM.CLUSTER.COMMAND.QUEUE' on queue manager 'QMNAME' failed
    with reason code 2150.
    
    AMQ6174: The dynamically loadable shared library
    '/var/mqm/exits64/MQADMIN_r' was not found.
    
    AMQ9448: Repository manager failed.  Retry in 10 minutes, queue
    manager will terminate in 7050 minutes.
    
    After the fix for IT15735, the sequence of errors is different,
    and updates to local cluster cache state are dropped,
    incorrectly.  If the queue manager has a dead letter queue, one
    or more messages will be put there, but there is no action the
    user can then take to handle those messages.
    
    Additionally it is possible this problem will be seen for
    certain types of internal MQ cluster state data arriving from
    remote cluster queue managers to this one.
    

Local fix

  • Correct the CCSID, if it was wrongly typed.
    Restart the queue manager so that the same CCSID is used
    throughout the queue manager, including the repository manager
    program.
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users who alter their QMGR CCSID, or (they cannot control this)
    receive internal cluster state messages with unconvertible
    characters from remote systems.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    The errors relate to character data within internal MQ command
    messages used by the clustering component of the queue manager.
    
    The cluster repository manager program (amqrrmfa) gets these
    messages from the SYSTEM.CLUSTER.COMMAND.QUEUE using MQGET with
    MQGMO_CONVERT.
    
    Messages will be put containing character fields encoded with
    the new CCSID.
    
    However, by design amqrrmfa (as with all application programs
    that connected before the change in the CCSID) will have cached
    the previous value of the CCSID at the time it connected.
    Therefore MQGET tries to convert the messages.
    
    If there is a defined conversion from the new CCSID to the
    previous (cached) CCSID, this will be likely to succeed.  But
    even so, there are some byte sequences that will not convert
    successfully.
    
    If the user has used unconvertible byte sequences in fields such
    as queue or channel descriptions, then these will cause the
    conversion to fail with reason codes such as 2150
    MQRC_DBCS_ERROR.
    
    At this point the behaviour is different at different fix packs:
    At levels not including the fix for IT15735: message at the top
    of the queue became a poison message, and caused the queue
    manager to end after a prolonged period where it is retried
    without success.
    At levels including the fix for IT15735: the message at the top
    of the queue is moved to the DLQ, if one is defined.  The
    benefit is that the message is no longer a poison message.  But
    the downside is that that update was not made to the local
    cluster cache.  In the worst case this resulted in queues
    becoming expired and so invisible to applications.
    

Problem conclusion

  • The MQ queue manager code has been updated with additional logic
    to handle the situation at the point when 2150 MQRC_DBCS_ERROR
    is returned from MQGET.
    
    The field(s) which might contain unconvertible characters will
    be blanked out and the conversion will be retried.  If the
    conversion succeeds, the code can proceed to store that update
    with a blank description.  Error messages AMQ6174 and AMQ9880
    will be written, to inform the administrator.
    
    If the message is still unconvertible then it will be moved to
    the Dead Letter Queue and an error message will be written.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v7.5       7.5.0.9
    v8.0       8.0.0.8
    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

    IT19598

  • Reported component name

    WMQ BASE MULTIP

  • Reported component ID

    5724H7241

  • Reported release

    750

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2017-03-08

  • Closed date

    2017-08-02

  • Last modified date

    2017-08-02

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

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

    PI82623

Fix information

  • Fixed component name

    WMQ BASE MULTIP

  • Fixed component ID

    5724H7241

Applicable component levels

  • R750 PSY

       UP



Document information

More support for: WebSphere MQ
APAR / Maintenance

Software version: 7.5

Reference #: IT19598

Modified date: 02 August 2017


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