Determine whether or not each of the following four transaction execution histories is serializable. If a history is serializable, specify a serial order of transaction execution to which it is equivalent

A. r1[x] r2[y] w2[x] r1[z] r3[z] w3[z] w1[z]

B. w1[x] w1[y] r2[u] w2[x] r2[y] w2[y] w1[z]

C. w1[x] w2[y] r2[u] w1[z] w2[x] r2[y] w1[u]

D. w1[x] w2[u] w2[y] w1[y] w3[x] w3[u] w1[z]

Question

Engineering

Octavio Bryan

22 July, 07:14

Determine whether or not each of the following four transaction execution histories is serializable. If a history is serializable, specify a serial order of transaction execution to which it is equivalent

A. r1[x] r2[y] w2[x] r1[z] r3[z] w3[z] w1[z]

B. w1[x] w1[y] r2[u] w2[x] r2[y] w2[y] w1[z]

C. w1[x] w2[y] r2[u] w1[z] w2[x] r2[y] w1[u]

D. w1[x] w2[u] w2[y] w1[y] w3[x] w3[u] w1[z]

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Answers (1)

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Precious · Answer 1

Option D. w1[x] w2[u] w2[y] w1[y] w3[x] w3[u] w1[z]

Explanation:

The execution in the option D is correct. This is because there is more than one reasonable criterion.