IBM Support

IC87534: OPTIMIZER NOT CHOOSING FASTER OR-INDEX PATH WITH FUNCTIONAL INDEXES

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APAR status

  • Closed as program error.

Error description

  • Optimizer behavior can be confusing with functional indexes.
    Without an order by, functional indexes may be chosen with the
    appropriate filters and udr percall_cost settings.  With an
    order by, the faster path with the functional indexes may never
    be chosen (regardless of the udr percall_cost setting) -- the
    optimizer will favor a composite index that satisfies the order
    by.
    

Local fix

  • Optimizer directives indicating the functional indexes, plus
    increasing the udr percall_cost can cause the optimizer to
    choose the faster index paths with the functional indexes.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * query pick slow path with UDR in predicates                  *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Update to IDS-11.50.xC10                                     *
    ****************************************************************
    

Problem conclusion

  • Problem Fixed In IDS-11.50.xC10
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC87534

  • Reported component name

    INFORMIX SERVER

  • Reported component ID

    5725A3900

  • Reported release

    B50

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2012-10-25

  • Closed date

    2017-06-15

  • Last modified date

    2017-06-15

  • 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

    INFORMIX SERVER

  • Fixed component ID

    5725A3900

Applicable component levels

  • RB50 PSN

       UP

  • RB50 PSY

       UP

  • RB70 PSN

       UP

  • RB70 PSY

       UP



Document information

More support for: Informix Servers

Software version: B50

Reference #: IC87534

Modified date: 15 June 2017


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