Q32

MCQ2 marks, −0.67

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. $S_1: r_1(x)r_1(y)r_2(x)r_2(y)w_2(y)w_1(x)$ $S_2: r_1(x)r_2(x)r_2(y)w_2(y)r_1(y)w_1(x)$ Which one of the following options is correct?

(A)

$S_1$ is conflict serializable, and $S_2$ is not conflict serializable

(B)

$S_1$ is not conflict serializable, and $S_2$ is conflict serializable

(C)

Both $S_1$ and $S_2$ are conflict serializable

(D)

Niether $S_1$ nor $S_2$ is conflict serializable

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