PM58114: CONCURRENT 'LOCK TABLE' AND 'INSERT' ON A PBG TABLESPACE MAY CAUSE PAGE REGRESSION.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • Dump Title: PR3A,ABND=04E-00C90101,U=SAPADM  ,M=(N),C=910.DMC
    -DSNISDLE,M=DSNTFRCV,LOC=DSNIDM  .DSNICUMW:5003
    In data-sharing environment, one member was executing an appl
    with 'LOCK TABLE IN EXCLUSIVE MODE' on a PBG tablespace.
    After the 'LOCK TABLE', another member issued INSERTs in the
    locked table. Those INSERTs created a new part and inserted rows
    in the new part.
    When the appl with the 'LOCK TABLE' accessed the rows in the new
    part, it didn't take any locks on the new part.
    Concurrent access by the 'LOCK TABLE' appl and other appls on
    the new part caused page regression and missing rows.
    The missing rows caused ABEND04E RC00C90101 DSNICUMW:5003.
    

Local fix

  • Avoiding to use 'LOCK TABLE' on PBG tablespace.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All DB2 10 for z/OS and DB2 9 for z/OS       *
    *                 customers that issue                         *
    *                 LOCK TABLE IN SHARE MODE or LOCK TABLE       *
    *                 IN EXCLUSIVE MODE on a Partition By          *
    *                 Growth (PBG) table space can potentially     *
    *                 experience data regression when a new        *
    *                 partition is added.                          *
    ****************************************************************
    * PROBLEM DESCRIPTION: ABEND04E RC00C90101 DSNICUMW ERQUAL5003 *
    *                      Data loss due to regressed pages.       *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    For a PBG table space, locks are taken at each partition level
    instead of the entire table or table space when a LOCK TABLE IN
    EXCLUSIVE MODE SQL statement is issued. After the LOCK TABLE
    operation completed, another agent was allowed to proceed with
    an insert operation that forced the creation of a new partition.
    The agent that issued the LOCK TABLE then regressed the data
    rows in the new partition as it should have had exclusive access
    to the entire table.
    

Problem conclusion

  • DB2 code has been changed to detect if all partitions are locked
    in exclusive or shared modes and to then avoid growing the PBG
    table space into a new partition by another agent that is doing
    SQL INSERT or UPDATE operations.
    The failing agent will get a RC00C9008E return code to indicate
    a lock timeout condition.
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PM58114

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-02-14

  • Closed date

    2012-04-03

  • Last modified date

    2012-05-02

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

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

    UK77666 UK77667

Modules/Macros

  •    DSNISUPI
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • RA10 PSY UK77666

       UP12/04/19 P F204

  • R910 PSY UK77667

       UP12/04/19 P F204

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


More support for:

DB2 for z/OS

Software version:

910

Reference #:

PM58114

Modified date:

2012-05-02

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