UGC-NET | UGC NET CS 2015 Jun – II | Question 17
Which of the following concurrency protocol ensures both conflict serializability and freedom from deadlock?
(a)z – phase Locking
(b)Time stamp – ordering
(A) Both (a) and (b)
(B) (a) only
(C) (b) only
(D) Neither (a) nor (b)
Explanation: (a) z – phase Locking is a concurrency control method that guarantees serializability. The protocol utilizes locks, applied by a transaction to data, which may block (interpreted as signals to stop) other transactions from accessing the same data.
during the transaction’s life. 2PL may be lead to deadlocks that result from the mutual blocking of two or more transactions.
(b)Time stamp – ordering concurrency protocol ensures both conflict serializability and freedom from deadlock.
Only (b) is correct.
So, option (C) is correct option.
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