Question

Question 8 (1 point) An algorithm is a finite sequence of steps to solve a problem. It is an intermediate step before coding. Does the following algorithm have a lost update problem? Let x, y be common variables; let a, b be local variables. Producer: for (int i = 0; i < 10; i++) { lock (x) { a = x a ++; X-a; } } Consumer: for (int i 0; i <10; i++) lock (x) { ax a a; } No, this algorithm does not have a lost update problem. Yes, this algorithm can have a lost update problem.

Answer 1

Correct Answer:

No, this algorithm does not have a lost update problem.

Explanation:

Lost update problem:

The lost update problem occurs when more than two transactions try to read and update the same data item. When a transaction updates the value of a data item but it is overwritten by another transaction.

In the given algorithm, the locking system is used.

A lock is a special variable associated with the database item.

The common variable x is updated after getting the lock and no other transaction can update the same item at the same time. Only one transaction can update the common variable at the same time. If any other transaction wants to update the same item then it needs to wait until the other transaction will release the lock.

Here, producer and consumer both applying the lock before updating the value of the common variable.

So, the given algorithm doesn't have a lost update problem.