Activity Session History (ASH) represents the history of the activities of all recent active sessions captured efficiently through a circular buffer in memory and efficiently written to AWR to incur minimal overhead. The ASH data can be rolled up by different dimensions: TOP SQL, object, file, session, module, action, and so on.

The ASH report can be run through command line, by running the Oracle supplied SQL script located in $OH/rdbms/admin/ashrpt.sql.

Other way to access the ASH report is from the Database page. Choosing the Performance tab will generate a screen similar to the following.

Clicking “Run ASH Report.” brings up the Active Session History report:

This screen allows you to put the date and time of the start and finish times of the period in which you’re interested. Enter the date and time as needed and press the “Generate Report” button on the upper right. By default the date and time shows a 5-minute interval.

After you click the button, you will see the ASH report on the screen for that period. If you look carefully, you will see that the report resembles the STASPACK report; but since it comes from AWR data, the metrics in them are much more useful. A small portion of the screen is shown below: