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Consider the transactions $T1, T2, \:\text{and} \:T3$ and the schedules $S1 \:\text{and} \:S2$ given below. 

  • $T1: r1(X); r1(Z); w1(X); w1(Z) $
  • $T2: r2(Y); r2(Z); w2(Z) $
  • $T3: r3(Y); r3(X); w3(Y) $
  • $S1: r1(X); r3(Y); r3(X); r2(Y); r2(Z); w3(Y); w2(Z); r1(Z); w1(X); w1(Z) $
  • $S2: r1(X); r3(Y); r2(Y); r3(X); r1(Z); r2(Z); w3(Y); w1(X); w2(Z); w1(Z) $

Which one of the following statements about the schedules is TRUE?

  1. Only $S1$ is conflict-serializable.
  2. Only $S2$ is conflict-serializable.
  3. Both $S1$ and $S2$ are conflict-serializable.
  4. Neither $S1$ nor $S2$ is conflict-serializable.
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2 Answers

Best answer
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$S_1$ has no cycle hence, Conflict-Serializable

$S_2$ has cycle hence NOT Conflict-Serializable

Answer is option A.

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In s1 there is no cycle ..serial order of execution for s1 is t2 t3 and t1 in s2 there is cycle in precedence graph so not conflict serializable so ans is a
Answer:

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