IBM Support

IC95034: OPTIMIZER PROCESSES QUERY IN DIFFERENT ORDER THAN ON V10 WHICH SIGNIFICANTLY IMPACTS EXECUTION TIME

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APAR status

  • Closed as program error.

Error description

  • You have done migration or upgrade from v10 to v11.50 and above
    and you noticed that certain multi-table queries are being
    executed slower than on Informix v10. You have inspected the
    query plans and noticed that on new version of Informix the
    optimizer is processing tables in the order different than on
    v10. For example:
    
    v10: tab1 -> tab2 -> join..
    v11.50 and above: tab2 -> tab1 -> join...
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All 11.70 and 12.10 users.                                   *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * A query may have suboptimal query plan under the following   *
    * conditions:                                                  *
    *  - a correlated subquery exists                              *
    *  - a cartesian join is performed between 2 tables            *
    *  - one of the tables involved in cartesian join is           *
    * performing an index scan with table filters                  *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Update to IDS-11.70.xC8                                      *
    ****************************************************************
    

Problem conclusion

  • Problem Fixed In IDS-11.70.xC8
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC95034

  • Reported component name

    INFORMIX SERVER

  • Reported component ID

    5725A3900

  • Reported release

    C10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-08-20

  • Closed date

    2014-02-26

  • Last modified date

    2014-02-26

  • 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

  • RB70 PSN

       UP

  • RC10 PSN

       UP

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Document Information

Modified date:
26 February 2014