1Z0-062 · Question #164
Which statement is true regarding the startup of a database instance?
The correct answer is E. Instance recovery is not required if the database instance was shut down by using SHUTDOWN. Instance recovery is only triggered after an abnormal shutdown like SHUTDOWN ABORT or a crash, not after a clean shutdown using SHUTDOWN NORMAL, IMMEDIATE, or TRANSACTIONAL.
Question
Which statement is true regarding the startup of a database instance?
Options
- AThe instance does not start up normally and requires manual media recovery after a shutdown
- BUncommitted transactions are rolled back during the startup of the database instance after a
- CThere is no difference in the underlying mechanics of the startup whether the database is shut
- DMedia recovery is required when the database is shut down by using either the immediate option
- EInstance recovery is not required if the database instance was shut down by using SHUTDOWN
How the community answered
(57 responses)- A7% (4)
- B4% (2)
- C2% (1)
- D2% (1)
- E86% (49)
Why each option
Instance recovery is only triggered after an abnormal shutdown like SHUTDOWN ABORT or a crash, not after a clean shutdown using SHUTDOWN NORMAL, IMMEDIATE, or TRANSACTIONAL.
A clean shutdown leaves the database in a consistent state, so no media recovery is required on the next startup.
Rolling back uncommitted transactions occurs during instance recovery after an abnormal shutdown, not during a normal startup that follows a clean shutdown.
There is a significant difference - SHUTDOWN ABORT leaves the database in an inconsistent state requiring instance recovery, while NORMAL, IMMEDIATE, and TRANSACTIONAL shutdowns do not.
Media recovery is unrelated to clean shutdowns and is only needed to repair physical damage to data files or apply archived redo logs, not as a consequence of SHUTDOWN IMMEDIATE or TRANSACTIONAL.
When the database is shut down cleanly using SHUTDOWN NORMAL, IMMEDIATE, or TRANSACTIONAL, all transactions are either committed or rolled back before shutdown completes and all dirty buffers are flushed to disk. This leaves the database in a consistent state, so Oracle does not need to perform instance recovery - applying redo and rolling back uncommitted transactions - on the next startup.
Concept tested: Oracle instance recovery vs. clean shutdown types
Source: https://docs.oracle.com/en/database/oracle/oracle-database/19/admin/starting-up-and-shutting-down.html
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