Upgrade Oracle DBA 11g to Oracle Database 12c — Question 6

You want to reduce fragmentation and reclaim unused space for the sales table but not its dependent objects. During this operation, you want to ensure the following: i.Long-running queries are not affected. ii.No extra space is used. iii.Data manipulation language (DML) operations on the table succeed at all times throughout the process. iv.Unused space is reclaimed both above and below the high water mark.
Which alter TABLE option would you recommend?

Answer options

• A. DEALLOCATE UNUSED
• B. SHRINK SPACE CASCADE
• C. SHRINK SPACE COMPACT
• D. ROW STORE COMPRESS BASIC

Correct answer: A

Explanation

The correct answer is A, DEALLOCATE UNUSED, as it specifically reclaims the unused space without affecting dependent objects and ensures that DML operations can continue. The other options either do not meet the requirement of not using extra space or could potentially affect long-running queries.