Question discussion

Consider the schedule S: r3(C), r1(A), w2(A), w2(B), r3(B), w3(C), w3(A), where ri(X) and wi(X) denote read and write of item X by transact…

1347Medium DSSSB TGT Computer Science 0 replies

Consider the schedule S: r3(C), r1(A), w2(A), w2(B), r3(B), w3(C), w3(A), where ri(X) and wi(X) denote read and write of item X by transaction Ti. Which serial schedule is conflict-equivalent to S?

AS is not conflict serializable
BT3 → T1 → T2
CT2 → T1 → T3
DT1 → T2 → T3

Correct answer: D

Explanation

The conflicts give edges T1 → T2 (r1(A), w2(A)), T1 → T3, T2 → T3 (w2(A), w3(A) and w2(B), r3(B)); the precedence graph is acyclic and its only topological order is T1, T2, T3.

Join the discussion Report an error

Discussion 0

Nobody has replied yet. Start the discussion!