On an 11.2.0.3.0 instance the AWR retention period is 8 days. Data in DBA_HIST_ACTIVE_SESS_HISTORY starts from 2014-04-30 but the corresponding SNAP_ID is not available in DBA_HIST_SNAPSHOT. DBA_HIST_SNAPSHOT only has data starting from 2004-05-11.
Why do these tables have different retention preiods?
