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PI74146: MQ 8.0 Z/OS-HIGH CPU CONSUMPTION IN CHIN - CLIENT CHANNEL MQMONNTP BROWSING MESSAGES ON QUEUE BEFORE MQ V7

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APAR status

  • Closed as program error.

Error description

  • ERROR DESCRIPTION:Ø
    Client channel (running mqmonntp.exe) was is browsing
    messages on queue. But the message on the queue before
    MQ v7 and rstCheckForOneMessage was continually trying
    to retrieve.
    The problem is that the MQGET processing keeps returning
    MQRC_TRUNCATED_MSG_FAILED with DataLength set to the
    length of the message, x561, although a large enough
    buffer has been supplied, x561.
    The problem was in CSQIMGE5 when processing a message
    put before MQ V7 (i.e. in an IRH2) which contains an
    RFH2 (len_moved is not updated with the length of the
    RFH2 put into the buffer by CSQMHDRS).
    .
    Additional Symptom(s) Search Keyword(s):
    MQMON
    MQMON session
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 8 *
    *                 Release 0 Modification 0.                    *
    ****************************************************************
    * PROBLEM DESCRIPTION: Client application getting a message    *
    *                      with message properties in a            *
    *                      message handle can cause the CHIN       *
    *                      address space to loop resulting         *
    *                      in high CPU usage.                      *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    Messages created in pre-V7 queue managers that have remained in
    queues after migration to V8 and they have RFH2 headers can
    cause the CHIN loop when a client application gets the message
    with option MQGMO_PROPERTIES_IN_HANDLE or
    MQGMO_PROPERTIES_AS_Q_DEF and the queue has attribute
    PROPCTL(ALL).
    

Problem conclusion

  • CSQIMGE5 has been updated to process pre-V7 messages with
    RFH2 correctly without causing the CHIN to loop.
    000Y
    CSQIMGE5
    

Temporary fix

  • *********
    * HIPER *
    *********
    

Comments

APAR Information

  • APAR number

    PI74146

  • Reported component name

    WMQ Z/OS 8

  • Reported component ID

    5655W9700

  • Reported release

    000

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-12-22

  • Closed date

    2017-05-18

  • Last modified date

    2017-05-18

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

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

    PI81299 UI47357

Modules/Macros

  • CSQIMGE5
    

Fix information

  • Fixed component name

    WMQ Z/OS 8

  • Fixed component ID

    5655W9700

Applicable component levels

  • R000 PSY

       UP



Document information

More support for: WebSphere MQ

Software version: 8.0

Reference #: PI74146

Modified date: 18 May 2017


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