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PM81754: ABEND U0796 DURING REPL CALL ON PHIDAM 13/01/30 PTF PECHANGE

A fix is available

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APAR status

  • Closed as program error.

Error description

  • Customer has applications that use multiple jobs to process a
    PHIDAM database with each job only processing one partition.
    The application does this by maintaining its own table of the
    High Keys for each of the partitions. When they want to process
    a selected partition (for example, partition 5) they will issue
    a GHU call using a GT operator using the High Key value from
    the previous partition. (4 in this example). This will cause
    IMS to position the job at the first key within the partition
    they are going to process. This caused a U0796 abend for one
    of the jobs.  A GHU with a GT operator was specified and
    returned the next highest key that matched the request.
    However on the following REPL call to update that segment,
    the U0796 abend was issued.
    The customer was was able to reproduce the U0796 using
    DFSDDLT0. Further analysis revealed there were no records in
    the first PHIDAM partition. The only record was the X'FF' key.
    The actual data that was returned from the GHU call was the
    first record in the next partition.
    Using the customer's scenario, the U0796 was recreated at SVL
    and the culprit was linked to V12 APAR PM53588.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All IMS V11 Full Function HALDB PHIDAM users *
    *                 with multiple partitions issuing a GHU call  *
    *                 followed by a REPL call.  Also, this problem *
    *                 occurs only after apar PM51794 / ptf UK82802 *
    *                 is applied.                                  *
    ****************************************************************
    * PROBLEM DESCRIPTION: When attempting to replace ( REPL ) the *
    *                      first root segment in the second and    *
    *                      subsequent HALDB partitions after       *
    *                      issuing a GHU call to retrieve the      *
    *                      root segment, the REPL call fails with  *
    *                      an ABENDU0796, which indicates an       *
    *                      attempt to replace a segment when the   *
    *                      lock on the segment is not held.        *
    ****************************************************************
    * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
    ****************************************************************
    After apar PM51794 / ptf UK82802 is applied, an attempt to
    replace ( REPL ) the first root segment of the second and
    subsequent partitions of a HALDB fails with an ABENDU0796.  Code
    added by apar PM51794 / ptf UK82802 forced the lock on the all
    X'FF' key to be gotten and released when crossing the HALDB
    partition boundary.  When the lock on the all X'FF' key is
    released flag JCBREPET is not reset.  DFSPSEL0 is then called to
    select the next partition.  Because flag JCBREPET was not reset,
    the expected root segment in the next partition is retrieved,
    but the enqueue call to get the lock on the root segment is
    skipped.  When the REPL call is then attempted, the ABENDU0796
    occurs.
    

Problem conclusion

  • GEN:
    KEYWORDS:
    
    *** END IMS KEYWORDS ***
    The following module has been modified to correct the reported
    problem:
    
    ************
    * DFSDLR00 *
    ************
    Code has been added in the BYKEY routine, after label KEYEND50,
    to reset flag JCBREPET after the dequeue of the lock on the
    all X'FF' key is done.  This will then allow the enqueue of
    the lock on the root segment retrieved in the next partition
    to be done correctly.
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PM81754

  • Reported component name

    IMS V11

  • Reported component ID

    5635A0200

  • Reported release

    101

  • Status

    CLOSED PER

  • PE

    YesPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2013-01-30

  • Closed date

    2013-03-29

  • Last modified date

    2013-05-06

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

    PM81487

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

    UK93038

Modules/Macros

  • DFSDLR00
    

Fix information

  • Fixed component name

    IMS V11

  • Fixed component ID

    5635A0200

Applicable component levels

  • R101 PSY UK93038

       UP13/04/02 P F304 «

Fix is available

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Document Information

Modified date:
06 May 2013