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PI26733: WMQ Z/OS: DETECT INCORRECT PAGE REUSE

A fix is available

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APAR status

  • Closed as program error.

Error description

  • The initial problem report was that an indexed queue
    experienced an ABEND5C6-00C93100 ( CSQI_KEYED_READ_FAILURE ) in
    CSQIMGE1.  An IKR control block existed for the message being
    gotten at the time of the abend, however the key in the IKR did
    not match with the value in the message on the associated IRH9
    page. The page had been reused.
    
    Another symptom was an unexpected MQRC 2033
    MQRC_NO_MSG_AVAILABLE for a message that should have been
    available on the queue.
    
    The page reuse could also happen for a non-indexed queue.
    
    Because the symptom may occur hours after the problem initially
    occurs, additional coding is needed to catch the page reuse at
    the time it initially happens and help find the root cause of
    the problem.
    
    Additional Symptom(s) Search Keyword(s):
    5C6 00E7014F ABEND5C6 ABENDS5C6 S5C6 S05C6 00C93100
    2195 MQRC_UNEXPECTED_ERROR
    CSQWDPRD DMC bad findpag
    

Local fix

  • CLEAR QLOCAL can be used to clear the message from the queue.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 *
    *                 Release 1 Modification 0.                    *
    ****************************************************************
    * PROBLEM DESCRIPTION: Additional checking for unexpected page *
    *                      reuse.                                  *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    If IRH9 pages used to storage messages are unexpectedly reused
    (a situation which should not occur), there is a possibility
    that incorrect data could be returned.
    

Problem conclusion

  • Additional defensive checks are added to CSQIMGE9 to detect
    unexpected IRH9 page reuse. When an IRH9 page is detected as
    having been incorrectly reused, abend 5C6-00C90D06 will be
    issued and the MQGET call will return MQRC_UNEXPECTED_ERROR
    (MQRC 2195).
    100Y
    CSQIMGE9
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PI26733

  • Reported component name

    WMQ Z/OS V7

  • Reported component ID

    5655R3600

  • Reported release

    100

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2014-09-30

  • Closed date

    2014-10-22

  • Last modified date

    2014-12-01

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

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

    PI27496 UI22397

Modules/Macros

  • CSQIMGE9
    

Fix information

  • Fixed component name

    WMQ Z/OS V7

  • Fixed component ID

    5655R3600

Applicable component levels

  • R100 PSY UI22397

       UP14/11/13 P F411 Ž

Fix is available

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Document Information

Modified date:
01 December 2014