Examine the query and its output: What might have caused three of the alerts to disappear?
A.
The threshold alerts were cleared and transferred to d0A_alert_history.
B.
An Automatic Workload Repository (AWR) snapshot was taken before the execution of
the second
C.
An Automatic Database Diagnostic Monitor (ADOM) report was generated before the
execution of the second query.
D.
The database instance was restarted before the execution of the second query.
It should be A.
the database instance may was restarted , it should be D
Answer A. Not D, because when instance was restarted, the alert will still exists in the dba_outstanding_alerts view.
If instance was restarted the Current Logons and “Application” event wait alerts would indeed disappear. However db_recovery_file_dest_size alert would remain. So not D.
Outstanding alerts do not clear after AWR/ADDM.
Therefore ->
Answer: A