Q8 /20 Choose the correct description of database rollforward processing.

Rollforward processing is a recovery technique used after a physical failure (like hardware crash or media failure) has occurred. It restores the database to a consistent state by reapplying committed transactions from the journal/transaction log after the backup has been restored. This is distinct from rollback, which undoes uncommitted transactions before a failure. Options A and C are incorrect because rollforward happens after the failure event, not before. Option D incorrectly associates rollforward with logical failures (user errors, incorrect updates), which are typically handled by rollback operations instead.

Step-by-step Derivation:
Rollforward vs. Rollback Analysis:

1. Rollforward = redo/reapply committed transactions from journal after restoring from backup (used for PHYSICAL failures like disk crash)
2. Rollback = undo uncommitted transactions (used for LOGICAL failures like accidental DELETE, incorrect UPDATE)
3. Timing: 'after updating' means after the failure has occurred and backup restored, then reapply changes
4. Failure type: 'physical failure' refers to hardware/media failures requiring full restoration
   → Correct answer: B (after physical failure)