Let r i (z) and w i (z) denote read and write operations respectively on a data item z by a transaction T i . Consider the following two schedules. S 1 : r 1 (x) r 1 (y) r 2 (x) r 2 (y) w 2 (y) w 1 (x) S 2 : r1(x) r 2 (x) r2(y) w2(y) r 1 (y) w1(x) Which one of the following options is correct?

Correct Answer is : S1 is not conflict serializable, and S2 is conflict serializable.

S 1 is conflict serializable, and S 2 is not conflict serializable.

S 1 is not conflict serializable, and S 2 is conflict serializable.

Both S 1 and S 2 are conflict serializable.

Neither S 1 nor S 2 is conflict serializable.

GATE Computer Science (CS) 2021 Shift 1 Solved Paper

Question : 42 of 65

Marks: +1, -0

Let r_i(z) and w_i(z) denote read and write operations respectively on a data item z by a transaction T_i. Consider the following two schedules.
S₁ : r₁(x) r₁(y) r₂(x) r₂(y) w₂(y) w₁(x)
S₂ : r1(x) r₂(x) r2(y) w2(y) r₁(y) w1(x)
Which one of the following options is correct?

S₁ is conflict serializable, and S₂ is not conflict serializable.
S₁ is not conflict serializable, and S₂ is conflict serializable.
Both S₁ and S₂ are conflict serializable.
Neither S₁ nor S₂ is conflict serializable.

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