Oracle Database Administration I — Question 69

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

Answer options

• A. An undo segment may be used by multiple transactions simultaneously
• B. Undo segments can wrap around to the first extent when a transaction fills the last extend of the undo segment
• C. Undo segments have a minimum of three extents
• D. Undo segments can extend when a transaction fills the last extent of the undo segment
• E. A single transaction may use multiple undo segments simultaneously
• F. Undo segments must be stored in a BIGFILE tablespace
• G. Undo segments must be stored in a SMALLFILE tablespace

Correct answer: A, B, D

Explanation

Option A is correct because multiple transactions can indeed use the same undo segment concurrently. Option B is accurate as undo segments can wrap back to the first extent when filled. Option D is also true since undo segments can extend when necessary. Options C, E, F, and G are incorrect as they do not accurately reflect the behavior and requirements of undo segments in Oracle databases.