Active Session History Statistics

Active Session History Statistics
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The Active Session History (ASH) statistics are samples of session activity in the
database. The database samples active sessions every second and stores them in a
circular buffer in the System Global Area (SGA). Any session that is connected to the
database and using CPU, or is waiting for an event that does not belong to the idle
wait class, is considered an active session. By capturing only active sessions, a
manageable set of data is represented. The size of the data is directly related to the
work being performed, rather than the number of sessions allowed on the database.