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IT28994: Potential for message loss or duplication when resolving indoubtmessage batch sent from shared channel

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APAR status

  • Closed as program error.

Error description

  • APAR IT27810 prevents multiple channel instances originating
    from the same partner from starting by checking a combination of
    channel name, queue manager name and queue manager identifier
    for uniqueness.
    
    Shared channels initiated from a z/OS queue sharing group (QSG)
    may be started from any queue manager in the queue sharing
    group. The channel sends the queue sharing group name instead of
    the queue manager name, however the queue manager identifier
    that is sent does correspond to the originating queue manager.
    
    The logic added in IT28710 to prevent multiple channel instances
    does not cater for shared channels where instances are started
    from multiple queue managers in the queue sharing group. This
    can then lead to the potential for message loss or duplication
    as described in IT27810.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users that send messages using shared channels from a z/OS queue
    manager to a distributed queue manager are potentially affected.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    The logic to detect an attempt to start more than one channel
    instance from a unique source does not consider that a z/OS
    shared channel could be started from different queue managers
    from within a queue sharing group, but that the queue sharing
    group should be considered as a single unique source.
    

Problem conclusion

  • The logic to prevent multiple channel instances from running on
    a distributed queue manager is modified to disregard the queue
    manager identifier (QMID) for the purposes of checking
    uniqueness when the peer is a shared z/OS channel.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v8.0       8.0.0.13
    v9.0 LTS   9.0.0.8
    v9.1 CD    9.1.3
    v9.1 LTS   9.1.0.3
    
    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

    IT28994

  • Reported component name

    IBM MQ BASE MP

  • Reported component ID

    5724H7251

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-04-30

  • Closed date

    2019-06-12

  • Last modified date

    2019-07-09

  • 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 MP

  • Fixed component ID

    5724H7251

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":"8.0.0.0","Edition":"","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
09 July 2019