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IZ49936: UNDER CERTAIN CONDITIONS, OPTIMIZER MAY PICK LESS THAN OPTIMAL ACCESS PLAN DUE TO OVER-ESTIMATED CARDINALITY

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • when only one derived table is referenced in its own query
    block, within the query block if there is a distinct requirement
    and one or more predicates applied to filter the stream, the
    combination may lead to overestimated cardinality and may result
    in a less than optimal access plan.
    

Local fix

Problem summary

  • UNDER CERTAIN CONDITIONS, OPTIMIZER MAY PICK LESS THAN OPTIMAL
    ACCESS PLAN DUE TO OVER-ESTIMATED CARDINALITY
    

Problem conclusion

  • Problem was first fixed in version 9.5 Fixpak 5
    

Temporary fix

Comments

APAR Information

  • APAR number

    IZ49936

  • Reported component name

    DB2 UDB ESE AIX

  • Reported component ID

    5765F4100

  • Reported release

    950

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2009-04-23

  • Closed date

    2009-12-19

  • Last modified date

    2009-12-19

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

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

    IC64058

Fix information

  • Fixed component name

    DB2 UDB ESE AIX

  • Fixed component ID

    5765F4100

Applicable component levels

  • R950 PSY

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 950

Reference #: IZ49936

Modified date: 19 December 2009