Oracle Database Administration II — Question 18

Which three are true about monitoring waits for sessions and services? (Choose three.)

Answer options

• A. V$SESSION_EVENT displays all waits for all past and existing sessions if the wait has occurred at least once for a session.
• B. V$SERVICE_EVENT displays all waits for all services if the wait has occurred at least once for a service.
• C. V$SESSION_WAIT_CLASS displays waits broken down by wait class only for waiting sessions.
• D. V$SESSION_WAIT and V$SESSION both contain details of the event on which a non-waiting session last waited.
• E. V$SESSION_EVENT displays all waits for all past sessions if the wait has occurred at least once for a session.
• F. V$SESSION_WAIT and V$SESSION both contain details of the event on which a session is currently waiting.

Correct answer: B, D, F

Explanation

The correct answers B, D, and F accurately describe the behavior of the respective views regarding waits for services and sessions. Option A is incorrect as it refers to past sessions instead of current sessions for V$SESSION_EVENT. Option C is misleading because V$SESSION_WAIT_CLASS applies to waiting sessions, not just any session. Option E incorrectly states that V$SESSION_EVENT includes all past sessions, which is not the case.