http://www.adp-gmbh.ch/ora/misc/dynamic_performance_views.html#system_event
v$system_event
If
timed_statistics is set to true, the sum of the
wait times for all
events are also displayed in the column
time_waited.
The unit of time_waited is one hundreth of a second. Since 10g, an additional column (
time_waited_micro) measures wait times in millionth of a second.
total_waits where event='
buffer busy waits' is equal the sum of
count in
v$waitstat.
v$enqueue_stat can be used to break down waits on the
enqueue wait event.
While this view totals all events in an instance,
v$session_event breaks it down to all currently connected
sessions.
