You notice that the performance of your production 24×7 Oracle 12c database has significantly degraded. Sometimes, you are not able to connect to the database
instance because it hangs.
How can you detect the cause of the degraded performance?
A.
by performing emergency monitoring using Real-Time Automatic Database Diagnostic Monitor (ADDM) to fetch data directly from SGA for analysis
B.
by running ADDM to fetch information from the latest Automatic Workload Repository (AWR) snapshots
C.
by using Active Session History (ASH) data and performing hang analysis
D.
by running ADDM in diagnostic mode