IBM Support

IT04002: QUERY PERFORMANCE DEGRADATION MAY OCCUR DUE TO A BAD FILTER FACTOR WHEN ORACLE COMPATIBILITY MODE IS ON.

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APAR status

  • Closed as program error.

Error description

  • When Oracle Compatibility Mode (VARCHAR2 mode) is on, one of
    index scan may end up with a wrong filter factor(0.4), which
    will lead to bad performance.
    
    You may see the following plan under IXSCAN, which shows 0.4
    filter factor, when the actual filter factor is less.
    
                    10) Start Key Predicate,
                            Comparison Operator:            Equal
    (=)
                            Subquery Input Required:        No
                            Filter Factor:                  0.04
    
                            Predicate Text:
                            --------------
                            (Q33.C1 = ORA_VARCHAR(:L33))
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 9.7 Fix Pack 11                               *
    ****************************************************************
    

Problem conclusion

  • First fixed in DB2 9.7 Fix Pack 11
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT04002

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2014-08-25

  • Closed date

    2017-05-03

  • Last modified date

    2017-05-03

  • 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 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSN

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.7

Reference #: IT04002

Modified date: 03 May 2017