Example of a rule-of-thumb definition

This example shows how to define your rule of thumb on the Definition page of the Rule-of-Thumb Properties window.

Assume the following:

You want to analyze specific data of the Buffer Pool Read report block of the DB2PM_STAT_BUFFER table. If the result of dividing the value in the NO_PREFETCH_NO_BUF column by the value in the SEQ_PREFETCH_REQ column is greater than 0.01, you want to get a warning. If the result exceeds 0.05, you want to be informed that a problem exists. In both cases, you want to give the recommendation that the EDM pool must be increased. In addition, you want the analysis result to include the value of the SEQ_PREFETCH_REQ column.

Your selections and specifications would then look as follows:
  1. In the Report block list, click BUFFER POOL READ.
  2. In the Columns box, click NO_PREFETCH_NO_BUF and then click Add (Add button) next to the VALUE expression box.

    The selected column is added to the VALUE expression box, preceded by the table name.

  3. In the Columns box, click SEQ_PREFETCH_REQ and then click Add (Add button) next to the VALUE expression box.

    The selected column is added to the VALUE expression box, preceded by the table name. Performance Expert leaves a space between this and the previously added column.

  4. In the VALUE expression box, type the operator / between the two columns to specify the division.
  5. In the Columns box, click SEQ_PREFETCH_REQ and then click Add (Add button) next to the Additional columns box.
  6. In the VALUE list (under WARNING and PROBLEM thresholds), click the operator > because you want to be notified when the result of the previously selected columns exceeds a certain value.
  7. In the WARNING threshold field, type 0.01.
  8. In the PROBLEM threshold field, type 0.05.
  9. In both Recommendation fields, type Increase BP size as needed.