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LI73147: IMPROVE FILTER FACTOR ESTIMATES FOR PREDICATES ON OLAP FUNCTION ROW_NUMBER()

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • This fix will improve filter factor estimates for a predicate
    on an olap function, row_number().
    .
    For example:
    .
    select *
    from (  select t1.*,
                   row_number() over (partition by c1, c2, c3) as
    rownum
            from t1 ) a
    where a.rownum = 1;
    .
    We would compute better filter factors for the olap function
    predicate.
    

Local fix

Problem summary

  • This fix will improve filter factor estimates for a predicate
    on an olap function, row_number().
    .
    For example:
    .
    select *
    from (  select t1.*,
                   row_number() over (partition by c1, c2, c3) as
    rownum
            from t1 ) a
    where a.rownum = 1;
    .
    We would compute better filter factors for the olap function
    predicate.
    

Problem conclusion

  • module:  engn_sqno
    CSD >= V91 fixpack 6
    

Temporary fix

Comments

APAR Information

  • APAR number

    LI73147

  • Reported component name

    DB2 UDE ESE LIN

  • Reported component ID

    5765F4104

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2008-02-08

  • Closed date

    2008-11-03

  • Last modified date

    2008-11-03

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

    IZ15196

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

    LI73148

Modules/Macros

  • ENG_SQNO
    

Fix information

  • Fixed component name

    DB2 UDE ESE LIN

  • Fixed component ID

    5765F4104

Applicable component levels

  • R910 PSN

       UP

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Document Information

Modified date:
15 October 2021