Q43

MCQ2 marks, −0.67

Consider the database transactions T1 and T2 , and data items X and Y . Which of the schedule(s) is/are conflict serializable?

\begin{array}{|ll|} \hline \textbf{Transaction T1} \\ \text{R1(X)} \\ \text{W1(Y)} \\ \text{R1(X)} \\ \text{W1(X)} \\ \text{COMMIT(T1)} \\\hline \end{array} \quad \begin{array}{|ll|} \hline \textbf{Transaction T2} \\ \text{W2(X)} \\ \text{W2(Y)} \\ \text{COMMIT(T2)} \\\hline \end{array}

(A)

R1(X), W2(X), W1(Y), W2(Y), R1(X), W1(X), COMMIT(T2), COMMIT(T1)

(B)

W2(X), R1(X), W2(Y), W1(Y), R1(X), COMMIT(T2), W1(X), COMMIT(T1)

(C)

R1(X), W1(Y), W2(X), W2(Y), R1(X), W1(X), COMMIT(T1), COMMIT(T2)

(D)

W2(X), R1(X), W1(Y), W2(Y), R1(X), COMMIT(T2), W1(X), COMMIT(T1)

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