Based on how server process activity is identified, the best DBMS_MONITOR procedure will become apparent. Tracing and statistics collection are independently switched on and off by their own procedures; that is, if you want to trace and collect instance statistics, two procedures will be called to turn on the collection, and then two different procedures must be called to turn off the collection. A simple describe of DBMS_MONITOR will produce a couple pages of options. If you want to gather all actions for a specific module, you can use the dbms_monitor.all_actions procedure as an argument. Table 5-1 is sorted by turning collection on or off, and then tracing or statistics collection.

Don't be impatient. If you are collecting based on a group or type of user, make sure to collect plenty of data. DBAs tend to collect just enough data to do a cursory analysis, but you want enough data to perform a convincing analysis.

If you are collecting statistics, you must query from the appropriate view before you disable collection. If you first disable statistics collection and then query, zero rows will be returned.