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PK53844: ABEND U3957, WHEN DBRC DBDS RECORD EXISTS WITHOUT CORRESPONDING DB RECORD DUE TO A TIMING ISSUE.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • HPIC for IMS V8 and V9 reads the RECON directly because we can
    not get enough DBRC information by using the IMS RECON API in
    these releases.
    We're issuing an ENQ to read the DBDS record, then a DEQ.  We
    then ENQ a second time to read the DB record if the DBDS record
    is found.  This exposes a timing issue - by the time we try and
    read the DB record, it's gone (but we've read the DBDS record).
    This 2-phase approach was to avoid reserving RECON data sets
    for any length of time.
    Based on this problem, we're going to change HPIC to
    read the DBDS and DB records in the same ENQ/DEQ.
    

Local fix

  • No work around.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All IMS High Performance Image Copy for z/OS *
    *                 Version 3 Release 2 users ( FMID=H1J0320 )   *
    ****************************************************************
    * PROBLEM DESCRIPTION: HPIC terminates with ABEND U3957        *
    *                       ( ABENDU3957 ) when a DBDS record      *
    *                      exists in DBRC without a corresponding  *
    *                      DB record due to a timing issue.        *
    ****************************************************************
    * RECOMMENDATION: Apply the maintenance for this APAR.         *
    ****************************************************************
    HPIC terminates with ABEND U3957 ( ABENDU3957 ) when a DBDS
    record exists in DBRC without a corresponding DB record due to a
    timing issue.
    HPIC issues an ENQ to reads the DBDS record, then issues a DEQ.
    HPIC then issues an ENQ a second time to read the DB record if
    DBDS record is found.
    This exposes a timing issue - by the time HPIC tries to read the
    DB record, the DB record is not found in spite of reading the
    DBDS record successfully.
    This APAR changes HPIC to read both of the DB record and the
    DBDS record with reserving RECONs in the same ENQ.
    

Problem conclusion

  • FABJMAIN has been modified following things:
    - To call FABJRCHK with ENQ request.
    - To call FABJRCHK for reading the DB record.
    - To call FABJRCHK for reading the DBDS record.
    - To call FABJRCHK with DEQ request.
    
    FABJRCHK has been modified following things:
    - To call FABJARC0 for issuing ENQ RECONs and ENQ flag is on
         when ENQ request received from caller.
    - To call FABJARC0 for reading the DB record without ENQ request
         when ENQ flag is on.
    - To call FABJARC0 for reading the DBDS record without ENQ
         request when ENQ flag is on.
    - To call FABJARC0 for issuing DEQ RECONs and DEQ flag is on
         when DEQ request received from caller.
    
    FABJDBRC has been modified following things:
    - To call FABJRCHK with ENQ request.
    - To call FABJRCHK for reading the DB record.
    - To call FABJRCHK for reading the DBDS record.
    - To call FABJRCHK with DEQ request.
    
    The following modules have been reassembled.
      FABJDBR7 FABJDBR8 FABJDBR9 FABJRCH7 FABJRCH8 FABJRCH9
      FABJARC0
    

Temporary fix

Comments

APAR Information

  • APAR number

    PK53844

  • Reported component name

    IMS HP IMAGE CO

  • Reported component ID

    5655K9600

  • Reported release

    320

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2007-10-01

  • Closed date

    2007-10-31

  • Last modified date

    2007-12-03

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

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

    PK55693 UK30795

Modules/Macros

  • FABJARC0 FABJDBRC FABJDBR7 FABJDBR8 FABJDBR9
    FABJMAIN FABJRCHK FABJRCH7 FABJRCH8 FABJRCH9 FABUARCN
    

Fix information

  • Fixed component name

    IMS HP IMAGE CO

  • Fixed component ID

    5655K9600

Applicable component levels

  • R320 PSY UK30795

       UP07/11/02 P F711

Fix is available

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Document Information

Modified date:
14 December 2020