Q8 (20 points) Choose the correct description of database rollforward processing.

Database rollforward (also called redo or forward recovery) is the process of reapplying committed transactions from a journal/log file to restore a database to a desired state after a physical failure (such as hardware crash or media failure). It occurs after the failure is detected and corrected, replaying all committed changes forward from a backup checkpoint. Rollforward is used for physical failures (requiring media recovery), not logical failures (which use rollback).

Step-by-step Derivation:
Rollforward processing sequence: (1) Physical failure occurs (media damage, disk crash, etc.). (2) Database is restored from a backup copy. (3) Journal/transaction log is replayed forward to reapply all committed transactions made since the backup. (4) Database is brought to a consistent state reflecting all saved work. Key distinction: Rollforward = after failure, using journal to move forward from backup. Rollback = before/during failure, undoing uncommitted changes. Physical failure requires rollforward; logical failure requires rollback.