The Automatic Database Diagnostic Monitor (ADDM) analysis runs every 60 minutes on your database. Your database if facing a series of interrelated problems over a period of two hours. You need to ensure that the ADDM analysis is run over a time span of two hours in future.
What would you do?
Create two custom ADDM tasks.
Modify the AWR snapshot time interval to two hours.
Create a new scheduler window for a time period of two hours.
Modify the time interval by using the DBMS_JOB.INTERVAL procedure.
Modify the Automatic Workload Repository (AWR) snapshot retention period to two hours.
The Automatic Database Diagnostic Monitor (ADDM) provides a holistic tuning solution. ADDM analysis can be performed over any time period defined by a pair of AWR snapshots taken on a particular instance. Analysis is performed top down, first identifying symptoms and then refining them to reach the root causes of performance problems.
The goal of the analysis is to reduce a single throughput metric called DB time. DB time is the cumulative time spent by the database server in processing user requests. It includes wait time and CPU time of all non-idle user sessions. DB time is displayed in the V$SESS_TIME_MODEL and V$SYS_TIME_MODEL views.
REF.: Oracle(r) 10g Performance Guide, 6-12