Running ADDM Manually

By default, Oracle Database runs ADDM every hour, immediately after an AWR snapshot. Performance findings from the most recent ADDM run, if any, are listed on the Database Home page. See "Performance Self-Diagnostics: Automatic Database Diagnostic Monitor" for more information.

You can also run ADDM manually. Reasons for doing so include running it as a recommended action associated with an alert or running it across multiple snapshots.

The following steps describe how to run ADDM to analyze a period that spans multiple snapshots.

To run ADDM manually:

1. Go to the Database Home page.

   See "Accessing the Database Home Page".

2. Under Related Links at the bottom of the page, click Advisor Central.

   The Advisor Central page appears.

3. Click ADDM.

   The Run ADDM page appears.

4. Select Run ADDM to analyze past performance.

5. Complete the following steps to choose a period start time:

   1. Select the Period Start Time option.

   2. (Optional) Examine the timeline graph and note the number of snapshots available in each 2-hour period. Each snapshot is represented by a camera icon. If your snapshots occur more frequently than once each hour and you want to view the timeline of snapshots with more precision, then click the zoom-in icon at the right. (The zoom-in icon is a magnifying glass with a plus-sign.)

   3. (Optional) Below the timeline graph, click the left-arrow icon or right-arrow icon at the left and right sides of the page to change the period shown in the timeline graph.

   4. Click a camera icon.

      A bold right arrow indicating period start time covers the camera icon, and the Period Start Time field above the timeline graph changes to the selected date and time.

6. If you want a period end time other than the default (the most recent snapshot), then complete the following steps:

   1. Above the timeline graph, select the Period End Time option.

   2. (Optional) Click the left-arrow icon or right-arrow icon at the left and right sides of the page to change the period shown in the timeline graph.

   3. Click a camera icon.

      A bold square (like a stop button on a recording device) covers the camera icon, and the Period End Time field changes to the selected date and time.

7. Click OK to start the analysis.

   After a short delay, the Automatic Database Diagnostic Monitor page appears, showing its findings.

8. (Optional) In the Task Name list, note the task name.

   A typical task name is "Task_52." You can return to this analysis at a later time by searching for and selecting the task name in the Advisor Central page.