Which method or feature should you use?

You notice a performance change in your production Oracle 12c database. You want to know which change
caused this performance difference.
Which method or feature should you use?

A.
Compare Period ADDM report

B.
AWR Compare Period report

C.
Active Session History (ASH) report

D.
taking a new snapshot and comparing it with a preserved snapshot

Explanation:
The awrddrpt.sql report is the Automated Workload Repository Compare Period Report. The awrddrpt.sql script
is located in the $ORACLE_HOME/rdbms/admin directory.
Incorrect:
Not A: Compare Period ADDM
Use this report to perform a high-level comparison of one workload replay to its capture or to another replay of
the same capture. Only workload replays that contain at least 5 minutes of database time can be compared
using this report.