Space announcement This space provides the same content as before, but the organization of the home page has changed. The content is now organized based on logical branches instead of legacy book titles. We hope that the new structure will help you quickly find the content that you need.

Workload Statistics Advisor

The Workload Statistics Advisor component simplifies the process of selecting and updating those catalog statistics that help optimize access path decisions. Workload Statistics Advisor helps determine which catalog statistics, if updated, will reduce the cost of running a set of SQL statements.

When preparing a SQL statement, the Db2 optimizer bases its access path decisions on catalog statistics that refer to the objects participating in the statement. The BMC AMI Stats for Db2, BMCSTATS, and the IBM RUNSTATS utility calculate and update these statistics.

The advisor output includes a SQL Performance for DB2 Advisory that:

  • Compares Db2 optimizer predicted performance with Apptune observed performance
  • Identifies significant discrepancies between statements' predicted and observed performance

Typically, if a statement performs worse than expected, the reason is that the catalog statistics need to be updated. Statistics Advisor uses the following input to make recommendations for updating statistics and rebinding related packages:

  • Performance Advisory results
  • Db2 optimizer feedback about the columns and the types of statistics that can help maximize your SQL statements' performance

This section contains the following topic:


 

Tip: For faster searching, add an asterisk to the end of your partial query. Example: cert*