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PH11204: ABEND04E RC00C90101 DSNKFLOK ERQUAL1001

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APAR status

  • Closed as program error.

Error description

  • After an ALTER table got a dsnt375i deadlock and needed to
    rollback, this lead to an abend04e in dsnkflok at erqual1001 .
    The abend had the following title:
     DSN ,ABND=04E-00C90101,U=uuuuuuu ,M=N  ,C=121.DMC
     -DSNIRSVP,M=DSNTFRCV,LOC=DSNIDM  .DSNKFLOK:1001
                                                                   .
    During the backout of the ALTER, Index Manager was freeing the
    Fast Traverse Block structures and came acrosss another task
    holding a lock on the FTB .
                                                                   .
    Additional keywords: FTB p-lock . vrace1001 DB2FTB/K
    

Local fix

  • Turn off FTB.
    Defer the ALTER and materialise during REORG later, for example
    use DDL_MATERIALIZATION to ALWAYS_PENDING .
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All Db2 12 for z/OS users with indexes that                  *
    * are eligible for Fast Traverse Block (FTB)                   *
    * optimization.                                                *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * After an ALTER table got a dsnt375i                          *
    * deadlock and needed to rollback, this                        *
    * lead to an abend04e in dsnkflok at                           *
    * erqual1001.                                                  *
    *                                                              *
    * During the backout of the ALTER, Index                       *
    * Manager was freeing the Fast Traverse                        *
    * Block structures and came across                             *
    * another task holding a lock on the                           *
    * FTB.                                                         *
    *                                                              *
    * Additional keywords:                                         *
    * FTB p-lock vrace1001                                         *
    * DSNKFTIN ERQUAL5002                                          *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Apply corrective PTF when available                          *
    ****************************************************************
    The rollback of the ALTER table, also caused a rollback of
    an ALTERed index (triggered by the ALTER table).  The rollback
    of the ALTERed index marked the Index Descriptor (IXD) for
    removal, but the FTBs associated with the index were not freed.
    Then later processing on the member (where the rollback of the
    ALTER index occurred), could encounter a previous FTB plock
    being held, since the FTB(s) were not freed immediately during
    the rollback.
    

Problem conclusion

  • Index Manager code has been modified to immediately free FTB
    structures and their associated FTB plocks, whenever an IXD
    is being marked for removal.
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PH11204

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    C10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-04-18

  • Closed date

    2019-09-12

  • Last modified date

    2020-06-30

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

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

    UI65307

Modules/Macros

  • DSNKIXDB DSNKTRAV DSNKLOD2 DSNB1CPP DSNKFTOM DSNKUSET DSNKINSL
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • RC10 PSY UI65307

       UP19/09/27 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 July 2020