Oracle Database Administration I — Question 144

Which two statements are true about undo segments and the use of undo by transactions in an Oracle database instance? (Choose two.)

Answer options

• A. Undo segments can be stored in the SYSAUX tablespace.
• B. Undo segments can wrap around to the first extent when a transaction fills the last extend of the undo segment.
• C. A single transaction may use multiple undo segments simultaneously.
• D. Undo segments can extend when a transaction fills the last extent of the undo segment.
• E. Undo segments can be stored in the SYSTEM tablespace.

Correct answer: B, D

Explanation

The correct answers are B and D because B indicates that when the last extent is filled, undo segments can start using the first extent again, while D confirms that these segments can grow when they reach capacity. Options A and E are incorrect as undo segments are not stored in SYSAUX or SYSTEM tablespaces; they are typically stored in a dedicated undo tablespace. Option C is false because a single transaction generally uses one undo segment at a time.