GATE | Gate IT 2008 | Question 61

Consider the following three schedules of transactions T1, T2 and T3. [Notation: In the following NYO represents the action Y (R for read, W for write) performed by transac­tion N on object O.]

(S1)    2RA    2WA    3RC    2WB    3WA    3WC    1RA    1RB    1WA    1WB
(S2)    3RC    2RA    2WA    2WB    3WA    1RA    1RB    1WA    1WB    3WC
(S3)    2RA    3RC    3WA    2WA    2WB    3WC    1RA    1RB    1WA    1WB

Which of the following statements is TRUE?

(A) S1, S2 and S3 are all conflict equivalent to each other
(B) No two of S1, S2 and S3 are conflict equivalent to each other
(C) S2 is conflict equivalent to S3, but not to S1
(D) S1 is conflict equivalent to S2, but not to S3

Answer: (D)
Explanation:

All the conflicting pairs like (3WA, 1WA) are in the same order in both S1 and S2.
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