Q.Which of the following concurrency control protocols ensure(s) both conflict serializability and freedom from deadlock? I. 2-phase locking II. Timestamp ordering
Correct answer: II only
Explanation
2 phase locking (2PL) is a concurrency control method that guarantees serializability. The protocol utilizes locks applied by a transaction to data, which may block other transaction from accessing the same data during the transaction's life. 2PL may be lead to dead locks that result from the mutual blocking of two or move transactions.
2 phase locking (2PL) is a concurrency control method that guarantees serializability. The protocol utilizes locks applied by a transaction to data, which may block other transaction from accessing the same data during the transaction's life. 2PL may be lead to dead locks that result from the mutual blocking of two or move transactions.