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IT31996: QUERY WITH OUTER JOIN TOGETHER WITH "DBPARTITIONNUM() =" LOCAL PREDICATE NO LONGER GETS THE DESIRED PLAN.

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APAR status

  • Closed as program error.

Error description

  • query with outer join together with "dbpartitionnum() =" local
    predicate no longer gets the desired plan with the base access
    running on just one database partition. It can cause the worse
    performance comparing with the previous release.
    
    Once the customer has installed the ptf with the fix, they must
    also set the following registry variable to revert to the
    previous behavior:
    db2set DB2_EXTENDED_OPTIMIZATION="SEP_DBPTNUM ON"
    (This registry variable can be set dynamically).
    
    Note that this setting can be combined with existing settings.
    For example, if the current setting is
    DB2_EXTENDED_OPTIMIZATION=ON
    you can add the additional setting to the end, separated by a
    comma (no spaces) as follows:
    db2set DB2_EXTENDED_OPTIMIZATION="ON,SEP_DBPTNUM ON"
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * Db2 EEE configurations                                       *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to Db2 Version 11.1 Fix Pack m4fp6.                  *
    * Then set registry variable as described in the error         *
    * description.                                                 *
    ****************************************************************
    

Problem conclusion

  • Fixed in Db2 Version 11.1 Fix Pack m4fp6
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT31996

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-02-26

  • Closed date

    2021-03-19

  • Last modified date

    2021-03-19

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

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

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • RB10 PSN

       UP

[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSEPGG","label":"DB2 for Linux- UNIX and Windows"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.1","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
04 May 2022