PK74727: THE FILTER FACTOR OF THE MATCHING PREDICATE "COL >= ? AND COL <= ? " IN V9 IS INCORRECT

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• the filter factor of the matching predicate "col >= ?  and
  col <= ? " in v9 is incorrect
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: For all DB2 for z/OS users having a query    *
  *                 that has two range predicates on the same    *
  *                 index key column that can be combined and    *
  *                 used for index matching.                     *
  ****************************************************************
  * PROBLEM DESCRIPTION: The filter factor for index matching    *
  *                      is not correctly estimated when there   *
  *                      are two range predicates that can be    *
  *                      combined on the same index key column.  *
  *                                                              *
  *                      For example,                            *
  *                      SELECT ...                              *
  *                      FROM ...                                *
  *                      WHERE T1.C1>? AND                       *
  *                            T1.C1<? AND                       *
  *                            ...                               *
  *                                                              *
  *                      INDEX IX1 on T1(C1,...)                 *
  *                                                              *
  *                      Index IX1 could use both range          *
  *                      predicates on T1.C1 for index           *
  *                      matching.  However, currently the       *
  *                      combined filter factor is not           *
  *                      correctly estimated.                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When there are two range predicates that can be combined on the
  same index key column to be used for index matching, currently
  the combined filter factor is not correctly estimated.  It may
  cause DB2 to choose a non-optimal index.
  
  Additional Keywords:
  SQLACCESSPATH SQLINDEX SQLRANGE FILTERFACTOR
  

Problem conclusion

• This APAR will fix the filter factor estimation problem so that
  filtering of the two range predicates on the same index column
  can be correctly combined.
  

Temporary fix

Comments

APAR Information

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

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

  UK42301

Modules/Macros

• DSNXOGBM
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• R910 PSY UK42301

     UP08/12/25 P F812

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.