Advanced
Database Management Systems
Q81 / 100
What is the difference between 2PL (Two-Phase Locking) and MVCC?
Correct! Well done.
Incorrect.
The correct answer is B) 2PL acquires all locks before releasing any (expanding then shrinking phases), blocking readers; MVCC uses versions to allow readers and writers to proceed concurrently
B
Correct Answer
2PL acquires all locks before releasing any (expanding then shrinking phases), blocking readers; MVCC uses versions to allow readers and writers to proceed concurrently
Explanation
Strict 2PL: all locks released at commit, preventing cascading aborts. 2PL blocks readers with writers. MVCC lets readers see a consistent snapshot without blocking writers, improving concurrency at the cost of storage for old versions.
Progress
81/100