Monitoring User Activity

The Average Active Sessions chart of the Performance page shows the average load on the database. For example, if 20 sessions currently exist in a database, but only 2 are active at a specific time, then the number of active sessions at this time will be 2. The chart shows which active sessions are running on the CPU or waiting on an event.

By following the performance method explained in Oracle Database Performance Method, you can drill down from the charts to identify the cause of instance-related performance issues and resolve them.

To monitor user activity: 

1. From the Database Home page, click Performance.

   The Performance page appears.

2. Locate the spikes in the Average Active Sessions chart.

   Each component shows the average number of active sessions in the specified state for the specified time. For example, if only one session were active, then the value .8 for CPU would mean that the session consumed CPU in 4 of 5 sampled seconds around the target time. The Maximum CPU equals the number of CPUs on the system. When the CPU Used value reaches the Maximum CPU line, the database instance is running at 100 percent of CPU time on the host system.

   The wait classes show how much database activity is consumed by waiting for a resource such as disk I/O. Values that use a larger block of active sessions represent bottlenecks caused by a particular wait class, as indicated by the corresponding color in the legend.

3. To identify each wait class, move your cursor over the block in the Average Active Sessions chart corresponding to the class.

   The corresponding wait class is highlighted in the chart legend.

4. Click the largest block of color on the chart or its corresponding wait class in the legend to drill down to the wait class with the most active sessions.

   If you click CPU Used, then the Active Sessions Working page for the wait class appears. If you click a different wait class, such as User I/O, then the Active Sessions Waiting page appears.

   The Active Sessions Working page shows a 1-hour time line. Details for each wait class are shown in 5-minute intervals under Detail for Selected 5 Minute Interval.

   You can view the details of wait classes in different dimensions by proceeding to one of the following sections:

   • "Monitoring Top SQL"

   • "Monitoring Top Sessions"

   • "Monitoring Top Services"

   • "Monitoring Top Modules"

   • "Monitoring Top Actions"

   • "Monitoring Top Clients"

   • "Monitoring Top PL/SQL"

   • "Monitoring Top Files"

   • "Monitoring Top Objects"

5. To change the time selected interval, move the slider below the chart to a different interval.

   The information contained in the Detail for Selected 5 Minute Interval section is automatically updated to display the selected time period.

6. If you discover a performance problem, then you can attempt to resolve it in real time. On the Performance page, do one of the following:

   • Click a snapshot below the chart that corresponds to the time when the performance problem occurred to run ADDM for that time period.

     For information about ADDM analysis, see "Reviewing the Automatic Database Diagnostic Monitor Analysis".

   • Create a snapshot manually by clicking Run ADDM Now.

     For information about creating snapshots manually, see "Creating Snapshots". For information about running ADDM manually, see "Manually Running ADDM to Analyze Current Database Performance".

   • Click Run ASH Report to create an Active Session History (ASH) report to analyze transient, short-lived performance problems.

     For information about ASH reports, see "Active Session History Reports".