Let's assume there was an outstanding user activity, the performance was reported to be slow, but there is no more activity on the database, how would the DBA be able to identify what the problem was? The only possible way is by means of a tool that is able to generate a report of the past user activity, the Active Session History Report, known also as ASH.

You can view the Active Session History Report via the Performance tab. At the Average Active Sessions section you should see a button named Run ASH Report, clicking this will take you to the ASH report time frame specification, once the period of time has been set, the report can be generated.

Here you can see the time frame specification and the report header, for your convenience the report can be saved in HTML format for further analysis.

The Active Session History report is produced out of several AWR tables, the AWR takes a periodic activity snapshot and it stores the information for a given period...