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IT26459: SLOW PERFORMANCE MIGHT BE OBSERVED WHEN RUNNING AN IUD STATEMENTWITH CERTAIN CHARACTERISTICS

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APAR status

  • Closed as program error.

Error description

  • Slow performance might be observed when running an IUD statement
    with the following characteristics:
    1. the statement is run in a federated setup
    1. there is a correlated EXISTS predicate applied on the IUD
    target table
    2. the IUD target and the table selected in the EXISTS sub-query
    reside in different servers
    
    In order to take advantage of the fix, the below additional
    steps will need to be taken:
    
    Add this guideline to the problem query:
    /*<OPTGUIDELINES>
         <REGISTRY>
             <OPTION NAME='DB2_EXTENDED_OPTIMIZATION'
    VALUE='EXISTS_TO_JOIN_EXT ON'/>
         </REGISTRY>
    </OPTGUIDELINES>*/
    
    or to enable the extension at the instance level execute:
    
    db2set -im DB2_EXTENDED_OPTIMIZATION="EXISTS_TO_JOIN_EXT ON"
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All Federated users                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to version Upgrade to 11.1.4.7 and set variable as   *
    * described in above                                           *
    ****************************************************************
    

Problem conclusion

  • Fix provided in form of new optimization variable
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT26459

  • 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

    2018-09-28

  • Closed date

    2022-04-17

  • Last modified date

    2022-04-17

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

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

    IT41205

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

[{"Line of Business":{"code":"LOB10","label":"Data and AI"},"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"}]

Document Information

Modified date:
14 June 2022