ITPEC FE Subject A April 2024 Question 22
ITPEC FE Subject A April 2024 — Question 22 of 60
Deadlock Resolution — rollback is used to break a deadlock and return to normal state.
When a deadlock occurs (two or more transactions wait on each other's locks), the DBMS selects a victim transaction and performs a rollback:
- •Rollback — undoes all changes of the victim transaction, releasing its locks
- •The other transaction can then proceed normally
- •The rolled-back transaction can be retried
Why not others:
- (a) Commit — cannot commit a transaction that is stuck waiting for a lock
- (b) Drop — a DDL command to remove database objects; unrelated to deadlock resolution
- (d) Roll Forward — replays committed changes from the redo log during crash recovery, not during deadlock handling
Key rule: Deadlock → DBMS picks a victim → Rollback → locks released → normal state restored.
AI-generated — may contain errors
The original exam layout is preserved in the image so diagrams, formulas, tables, and code remain accurate.
This question comes from an official ITPEC past paper. ITPEC Practice is an independent study tool and is not affiliated with ITPEC. See the official FE past-paper collection or Report an issue.