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Consider the transactions T1, T2, and T3 and the schedules S1 and S2 given below.
T1: r1(X); r1(Z); w1(X); w1(Z)
T2: r2(Y); r2(Z); w2(Z)
T3: r3(Y); r3(X); w3(Y)
S1: r1(X); r3(Y); r3(X); r2(Y); r2(Z); w3(Y); w2(Z); r1(Z); w1(X); w1(Z)
S2: r1(X); r3(Y); r2(Y); r3(X); r1(Z); r2(Z); w3(Y); w1(X); w2(Z); w1(Z)
Which one of the following statements about the schedules is TRUE ?
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- Only S1 is conflict-serializable.
- Only S2 is conflict-serializable.
- Both S1 and S2 are conflict-serializable.
- Neither S1 nor S2 is conflict-serializable.
- Only S1 is conflict-serializable.
Correct Option: A
Precedence graph
∴ S1 is conflict serializable
