Managing AWR Snapshots

By default, the Automatic Workload Repository (AWR) generates snapshots of performance data once every hour, and retains the statistics in the workload repository for 8 days. You can change the default values for both the snapshot interval and the retention period.

Oracle recommends that you adjust the AWR retention period to at least a month. You can also extend the period to one business cycle so you can compare data across time frames such as the close of the fiscal quarter. You can also create AWR baselines to retain snapshots indefinitely for important time periods.

The data in the snapshot interval is analyzed by ADDM. ADDM compares the difference between snapshots to determine which SQL statements to capture, based on the effect on the system load. The ADDM analysis shows the number of SQL statements that need to be captured over time.

This section contains the following topics:

• Creating Snapshots

• Modifying Snapshot Settings