How Db2 Query Monitor creates a baseline performance window

When Db2 Automation Tool performs a build with the PERFORMANCE_OVERRIDE exception option specified in the exception profile, Db2 Query Monitor evaluates intervals and creates a baseline performance window.

If a reorganization is not needed, then Db2 Query Monitor proceeds to create a baseline performance window as follows:

• All intervals that are currently available in Db2 Query Monitor are analyzed to determine if they align with the performance window.
• If there are intervals that align with the performance window, those intervals are used to create a baseline.
• If no intervals align with the performance window, then Db2 Query Monitor selects a longer period than the performance window.
• If there are no intervals that align with the performance window timestamps, then Db2 Query Monitor waits for the next performance window.

If a reorganization is needed (the Reorg is needed flag is Y), then Db2 Query Monitor proceeds as follows:

• Db2 Query Monitor does not create a baseline because the object might be in an inappropriate state, as indicated by the fact that Db2 Automation Tool recommends a reorganization. If Db2 Query Monitor were to create a baseline, then all subsequent reorganizations would be rejected due to the inappropriate baseline.
• Db2 Query Monitor waits for the next performance window to determine if a baseline can be created at that time. When the next performance window occurs, Db2 Query Monitor determines the most recent reorganization of the objects of interest. If a reorganization was made against the objects of interest, then Db2 Query Monitor analyzes the performance window. Otherwise, a baseline is not created and Db2 Query Monitor continues to wait for the next performance window.