Manually Managing Undo Data (Rollback Segments)

Allocation of a Rollback Segment When a transaction begins, a rollback segment must be assigned to this transaction. A transaction can request a specific rollback segment using the following command: SET TRANSACTION USE ROLLBACK SEGMENT rollback_segment If no such request is made, the Oracle server chooses the rollback segment with the fewest transactions and assigns it to the transaction. Using Extents Transactions use extents of a rollback segment in a sequential, circular fashion, moving from one to the next after the current extent is full. A transaction writes an entry to its current location in the rollback segment and advances the current pointer by the...