Consider the following schedules,

S1: R1(A)W2(B)R2(A)W1(B)W3(B)W1(C)R3(B)W1(A) 
S2: W2(C)R1(A)W3(B)R1(C)R3(B)R3(A)W1(B)
S3: R3(B)R2(A)R1(A)R2(C)W3(A)W2(B)W1(C)
S4: W1(A)W2(B)W1(B)W2(A) 

Which of the following schedule are conflict serializable?
(A) S1 and S3
(B) S1 and S2
(C) S2 and S4
(D) S2 and S3


Answer: (B)

Explanation: S1, and S2 is conflict serializable with equivalent serial schedule T2T1T3 and ( T3T2T1 but S3 or T2T3T1 but S3and S4 is not conflict serializable due to R3(B) before W3(B) and R2(A) before W3(A) or { R2(C) before W1(A) and R1(A) before W3(A) R3(B) before W3(B) }W1(A) before W2(A) and W2(B) before W1(B) respectively.
So, option (B) is correct.

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  • Last Updated : 30 Nov, 2018

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