Give an example of a schedule in which a pessimistic concurrency control makes a transaction wait but then allows it to commit, while an optimistic concurrency control allows the transaction to commit without waiting.

What will be an ideal response?


The following schedule would be accepted by an optimistic control.
r1(x) r2(y) w1(z ) w2(z ) commit1 commit2
A pessimistic control would force the operation w2(z ) to wait.

Computer Science & Information Technology

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