Identify situations in which collecting statistics at the service level helps diagnosing performance problems. (Choose all that apply.)
A.
in a database where you want to monitor and diagnose individual sessions
B.
in a database where you want to statistically measure the workload of jobs
C.
in a database that supports an application where the client directly creates a session
D.
in multitier environments where a request from an end client is routed to different database sessions