IY71591: PREDICATE COST UNDERFLOW IN MGJN PLANS LEADS TO OPTIMIZER PICKING A SUB-OPTIMAL MGJN JOIN KEY

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • At very small cardinality estimates, MGJN predicate cost can
    become negligible. This can lead to a sub-optimal MGJN getting
    picked, when a more optimal one is available.
    

Local fix

Problem summary

  • Users Affected: ALL
    Problem Description: MGJN ispicked up in query access plan when
    it is not optimal to do so due to extremely small MGJN predicate
    cardinalities.
    Problem Summary:
    MGJN ispicked up in query access plan when
    it is not optimal to do so due to extremely small MGJN predicate
    cardinalities.
    

Problem conclusion

  • Problem fixed in version 8, fixpak 11
    

Temporary fix

Comments

APAR Information

  • APAR number

    IY71591

  • Reported component name

    DB2 UDB ESE AIX

  • Reported component ID

    5765F4100

  • Reported release

    820

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2005-05-13

  • Closed date

    2006-02-03

  • Last modified date

    2006-02-03

  • 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 UDB ESE AIX

  • Fixed component ID

    5765F4100

Applicable component levels

  • R820 PSY

       UP



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Document information


More support for:

DB2 for Linux, UNIX and Windows

Software version:

820

Reference #:

IY71591

Modified date:

2006-02-03

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