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IT33573: POOR PERFORMANCE OF FEDERATED QUERIES IN CERTAIN CASES

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • The issue is potential for poor performance of federated queries
    with a predicate which references a column in a single column
    unique index or constraint due to cardinality over-estimation.
    For example, using a hash join instead of nested loop join for a
    query which joins a local table to a federated table with a
    predicate which references the primary key of the federated
    table.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * all                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * fixed in db2_v111m4fp7                                       *
    ****************************************************************
    

Problem conclusion

  • fixed in db2_v111m4fp7
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT33573

  • 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

    2020-07-16

  • Closed date

    2021-07-05

  • Last modified date

    2021-07-05

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

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

    IT37511

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • RB10 PSN

       UP

  • RB50 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:
03 May 2022