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PH15068: IBM MQ Z/OS:ABN=5C6-00C92200 LOC=CSQILPLM.CSQIMPU2

A fix is available

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APAR status

  • Closed as program error.

Error description

  • If two tasks are both browsing and retrieving messages from a
    queue just as the queue goes empty, it's possible for one of
    the tasks to complete the operation without correctly clearing
    its allocation locks for the page, causing the following abend
    to occur some later time when the page is reused:
    ABN= 5C6-00E7014F
    ,LOC=CSQXADPM.CSQXADPM
    
    Once an orphaned lock has been created, it's possible that
    applications using any queue on the same pageset may be
    impacted as the lock is held at the pageset level. This means
    that other applications sharing the pageset (but not the
    problematic queue) can  also be impacted.
    
    Additional Symptom(s) Search Keyword(s):
    ABN= 5C6-00E7014F,
    ,LOC=CSQXADPM.CSQXADPM
    

Local fix

  • By no longer having multiple threads attempting to access the
    same pages related to a single queue, the problem should be
    avoided.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
    *                 Release 0 Modification 0 and Release 1       *
    *                 Modification 0.                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: When two applications browse a shared   *
    *                      queue concurrently messages may be      *
    *                      left locked.                            *
    *                      When the record that contained the      *
    *                      message is subsequently reused, abend   *
    *                      5C6-00C92200 occurs in CSQIMPU2 due     *
    *                      to the orphaned lock.                   *
    ****************************************************************
    When two applications browse and get messages from a shared
    queue concurrently specific timing situations can result in the
    cursor.locked field within the browse cursor being reset without
    the associated message record lock being freed immediately.
    As there is now no indication that a lock is held further browse
    processing may not free the lock either, and it can remain set
    until the application ends.
    The residual record lock information for the message can cause
    subsequent processing by this or another application sharing the
    queue to fail if an attempt is made to put a message to the same
    record/page/PSID as the allocation lock appears to be already
    set.
    

Problem conclusion

  • Browse lock processing has been changed for the reported
    problem to prevent Cursor.Locked being reset invalidly.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PH15068

  • Reported component name

    IBM MQ Z/OS V9

  • Reported component ID

    5655MQ900

  • Reported release

    000

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-07-30

  • Closed date

    2019-09-05

  • Last modified date

    2019-10-01

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

    PH13499

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

    UI65150 UI65151

Modules/Macros

  • CSQIMGE1 CSQIMGE3
    

Fix information

  • Fixed component name

    IBM MQ Z/OS V9

  • Fixed component ID

    5655MQ900

Applicable component levels

  • R000 PSY UI65150

       UP19/09/26 P F909 ¢

  • R100 PSY UI65151

       UP19/09/26 P F909 ¢

Fix is available

  • Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

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Document Information

Modified date:
01 October 2019