PM71866: SIMPLE OR CLASSIC PARTITIONED TABLESPACE EXTENDS RAPIDLY

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APAR status

  • Closed as program error.

Error description

  • Customer migrated from V8 to V10. They find simple tablespaces
    extend quite rapidly although most of the data pages have only
    holes and can not be reused.
    Lab can recreate the same problem with classic partition table
    space.
    The spacemap page was not updated correctly after delete.
    The problem is only under V10.
    

Local fix

  • Customer can alter the simple tablespace to a segmented table
    space to avoid such problem.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All DB2 10 for z/OS (CM and above) users of  *
    *                 non-segmented table spaces (simple table     *
    *                 spaces or classic-partitioned table spaces)  *
    ****************************************************************
    * PROBLEM DESCRIPTION: Non-segmented table space may grow      *
    *                      rapidly due to insert failing to reuse  *
    *                      deleted space                           *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    In DB2 10, for non-segmented table spaces, the first SQL DELETE
    against a full page mistakenly skip to update the space map
    page. According to the non-updated space map page, the data page
    still remain full incorrectly.
    
    As a result, a subsequent insert looked for space in a different
    page, resulting in unnecessary growth to the table space.
    
    If after the first SQL DELETE against a full page came another
    SQL DELETE, depending on the space situation on the page, the
    second SQL DELETE may or may not drive update of the space map
    page. Therefore, the problem of 'unupdated' space map page could
    continue even through several SQL DELETEs.
    
    The problem is more likely to happen in table spaces that have a
    lower MAXROWS value and small row sizes.
    

Problem conclusion

  • DB2 code has been modified to make sure that the first SQL
    DELETE against a full page properly updates the space map page
    so that a subsequent insert can reuse the deleted space.
    
    Additional keywords: SQLDELETE SQLINSERT
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PM71866

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    A10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-08-30

  • Closed date

    2012-10-26

  • Last modified date

    2012-12-04

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

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

    UK83061

Modules/Macros

  •    DSNIDILS DSNIDLEO
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • RA10 PSY UK83061

       UP12/11/13 P F211

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:

A10

Reference #:

PM71866

Modified date:

2012-12-04

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