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IT21033: COST OVER-ESTIMATE OF THE REFETCH DURING UPDATE/DELETE/MERGE OPERATION

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • During SQL statements with UPDATE and DELETE operations
    (including MERGE) the optimizer can over-estimate the cost of
    the reFETCH which can lead to choosing a plan using NLJN below
    the UPDATE/DELETE instead of a HSJN.
    The HSJN itself is correctly costed lower than the NLJOIN, but
    the issue is with the cost of the reFETCH operator below the
    UPDATE.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to Db2 Version 11.1 Mod 3 FixPack 3                  *
    ****************************************************************
    

Problem conclusion

  • First fixed in Db2 Version 11.1 Mod 3 FixPack 3
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT21033

  • 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

    2017-06-14

  • Closed date

    2018-03-19

  • Last modified date

    2018-03-19

  • 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":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.1","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
19 March 2018