IZ45441: EXP0147W "STATISTICAL VIEW MAY HAVE BEEN USED BY THE OPTIMIZER" DOES NOT CONFIRM IF THE STATISTICAL VIEW HAS INDEED BEEN USED

APAR status

• Closed as program error.

Error description

• This APAR is to address the message EXP0147W which states that a
  statistical view "may have been used". This could be misleading
  as there is not confirmation that the statistical view has
  indeed been used to estimate cardinality. The information in the
  exfmt output will confirm this fact (see "Objects Used in Access
  Plan):
  
  Objects Used in Access Plan:
  ---------------------------
  Schema: DBA_OWNER
  Name: FOND_STAT1
  Type: View (reference only)
  
  
  Suggested update of Info Center:
  The message indicates that the statistical view is matched and
  the optimizer has access to its statistics. In some
  situations, it may result in cardinality estimates that are
  differ to estimates which would have been made if the
  statistical view did not exist.   However, in other situations,
  cardinality estimation adjustments may not be observable.
  
  And change EXP0147W message text from "may have been used" to
  "was used"
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * ALL                                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * EXP0147W "STATISTICAL VIEW MAY HAVE BEEN USED BY THE         *
  * OPTIMIZER" DOES NOT CONFIRM IF THE STATISTICAL VIEW HAS      *
  * INDEED BEEN USED                                             *
  * This APAR is to address the message EXP0147W which states    *
  * that a                                                       *
  * statistical view "may have been used". This could be         *
  * misleading                                                   *
  * as there is not confirmation that the statistical view has   *
  *                                                              *
  * indeed been used to estimate cardinality. The information in *
  * the                                                          *
  * exfmt output will confirm this fact (see "Objects Used in    *
  * Access                                                       *
  * Plan):                                                       *
  *                                                              *
  *                                                              *
  *                                                              *
  * Objects Used in Access Plan:                                 *
  *                                                              *
  * ---------------------------                                  *
  *                                                              *
  * Schema: DBA_OWNER                                            *
  *                                                              *
  * Name: FOND_STAT1                                             *
  *                                                              *
  * Type: View (reference only)                                  *
  *                                                              *
  *                                                              *
  *                                                              *
  *                                                              *
  *                                                              *
  * Suggested update of Info Center:                             *
  *                                                              *
  * The message indicates that the statistical view is matched   *
  * and                                                          *
  * the optimizer has access to its statistics. In some          *
  *                                                              *
  * situations, it may result in cardinality estimates that are  *
  *                                                              *
  * differ to estimates which would have been made if the        *
  *                                                              *
  * statistical view did not exist.   However, in other          *
  * situations,                                                  *
  * cardinality estimation adjustments may not be observable.    *
  *                                                              *
  *                                                              *
  *                                                              *
  * And change EXP0147W message text from "may have been used"   *
  * to                                                           *
  * "was used"                                                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to v9.1FP8                                           *
  ****************************************************************
  

Problem conclusion

• Problem was first fixed in Version 9.1FP8
  

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:

  IZ45448

Fix information

• Fixed component name

  DB2 UDB ESE HP-

• Fixed component ID

  5765F4103

Applicable component levels