IBM Support

IT28243: MQ incorrectly writes channel completion messages to the channelinitiation queue for SVRCONN channels

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APAR status

  • Closed as program error.

Error description

  • IBM MQ incorrectly writes channel completion messages with an
    MQMD format of MQCHCOM to SYSTEM.CHANNEL.INITQ when SVRCONN
    channels end.
    
    These extraneous messages can lead to an increase of CURDEPTH on
    the SYSTEM.CHANNEL.INITQ which may inhibit the channel initiator
    from performing its scheduled tasks in a timely manner.
    
    Under extreme circumstances, the initiation queue may fill
    preventing new trigger messages from being queued.
    
    The queue manager error log may contain AMQ7208 error entries
    indicating that the channel initiation queue is full
    (MQRC_Q_FULL).
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Any users that connect clients to a queue manager could generate
    unnecessary channel completion messages for SVRCONN channels
    when the client connections are closed.
    
    Whether the extraneous messages have a noticeable impact on the
    normal operation of the channel initiator (channel triggering,
    channel retry and healthchecking) will depend upon the number of
    connections closures and the existing workload on the channel
    initiator.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    When a channel agent terminates, it performs a check to see if a
    channel initiator will be scheduled to wake in time to perform a
    channel retry, it may also produce a channel stopped event if
    configured - this process is unnecessary for SVRCONN channel
    agents.
    

Problem conclusion

  • The logic in channel termination was corrected to the expected
    behaviour for SVRCONN channel agents.
    
    ---------------------------------------------------------------
    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

    IT28243

  • Reported component name

    IBM MQ BASE MP

  • Reported component ID

    5724H7251

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-02-27

  • Closed date

    2019-05-17

  • Last modified date

    2019-05-17

  • 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:
17 May 2019