IBM Support

IC80528: OPTIMIZER MAY CHOOSE SUB-OPTIMAL ACCESS ON RANGE PARTITION TABLES EVEN WHEN THE IN PREDICATE DOES NOT FILTER ANY RECORD

Subscribe

You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • For a range partitioned table with detailed index statistics,
    the Optimizer might choose an in2join access plan for a query,
    which has only one IN predicate and that IN predicate does not
    filter any records i.e. filter-factor = 1. For example:
    
    SELECT * FROM FACT WHERE YEAR IN ( 2012, 2013, 2014, 2015, 2016
    );
    
    Here, all possible values of column YEAR are mentioned in the IN
    clause. So, a table-scan access plan will be optimal. However,
    the Optimizer might choose an in2join access plan graph as
    follows:
    
                      ...
                     NLJOIN
              /--------+---------\
          TBSCAN                 FETCH
            |                /-----+------\
     TABFNC: SYSIBM      IXSCAN     DP-TABLE: SCHEMA1
          GENROW           |             FACT
                     INDEX: SCHEMA1
                         INDEX1
    

Local fix

  • Try collecting non-detailed index statistics.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 version 9.7 Fix Pack 6                        *
    ****************************************************************
    

Problem conclusion

  • Problem was first fixed in DB2 version 9.7 Fix Pack 6
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC80528

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-12-20

  • Closed date

    2012-06-14

  • Last modified date

    2012-06-14

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

    IC80514

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

    IC84600

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 #: IC80528

Modified date: 14 June 2012