IC73991: RUNNING UPDATE STATISTICS MEDIUM AND HIGH RESULTS IN A SLOWER QU ERY PLAN THAN RUNNING UPDATE STATISTICS LOW OR DROP DISTRIBUTION

APAR status

• Closed as program error.

Error description

• Running update statistics medium and high results in a much
  slower query plan than running update statistics low or drop
  distributions only. This defect is also seen in 10.00.XC8.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users                                                    *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * A query with a join filter using column subscripts ( eg.     *
  * tab1.col1[1] = tab2.col1) may select a poorly performing     *
  * query plan. This is because the optimizer is incorrectly     *
  * using complete column statistics to estimate selectivity for *
  * a subscripted column.                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to 11.50.xC9 or higher.                              *
  ****************************************************************
  

Problem conclusion

• The problem has been fixed in 11.50.xC9.
  

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:

Fix information

• Fixed component name

  IBM IDS ENTRP E

• Fixed component ID

  5724L2304

Applicable component levels

• RB15 PSN

     UP