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Consider the following schedule:
S: r2(z),r2(y),w2(y),r3(y),w3(z),r1(x),w1(x) ,w3(y),w3(z),r2(x),r1(y), w1(y),w2(x)
Which of the following is true about above schedule S.
  • a)
    The schedule is serializable as T2, T3, T1
  • b)
    The schedule is serializable as T2, T1, T3
  • c)
    The schedule is serializable as T3, T2, T1
  • d)
    The schedule is not serializable
Correct answer is option 'D'. Can you explain this answer?
Verified Answer
Consider the following schedule:S: r2(z),r2(y),w2(y),r3(y),w3(z),r1(x...
The precedence graph of the given schedule is
There is a cycle in the precedence graph, the schedule is not serializable.
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Most Upvoted Answer
Consider the following schedule:S: r2(z),r2(y),w2(y),r3(y),w3(z),r1(x...
Explanation:

To determine whether a schedule is serializable or not, we need to check whether it is equivalent to some serial schedule. If it is equivalent to some serial schedule, then it is serializable, otherwise, it is not serializable.

Let's analyze the given schedule S step-by-step:

Step 1: T2 reads z

Step 2: T2 reads y

Step 3: T2 writes y

Step 4: T3 reads y

Step 5: T3 writes z

Step 6: T1 reads x

Step 7: T1 writes x

Step 8: T3 writes y

Step 9: T3 writes z

Step 10: T2 reads x

Step 11: T1 reads y

Step 12: T1 writes y

Step 13: T2 writes x

The above schedule is not serializable because it violates the conflict serializability property, which states that if two transactions T1 and T2 access the same data item, then either T1 must complete before T2 starts or T2 must complete before T1 starts. In the given schedule, we can see that T3 writes to y and z after T2 reads them, but before T2 writes to x. Therefore, we cannot find an equivalent serial schedule for the given schedule.

Hence, option D is the correct answer.
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Consider the following schedule:S: r2(z),r2(y),w2(y),r3(y),w3(z),r1(x),w1(x) ,w3(y),w3(z),r2(x),r1(y), w1(y),w2(x)Which of the following is true about above schedule S.a)The schedule is serializable as T2, T3, T1b)The schedule is serializable as T2, T1, T3c)The schedule is serializable as T3, T2, T1d)The schedule is not serializableCorrect answer is option 'D'. Can you explain this answer?
Question Description
Consider the following schedule:S: r2(z),r2(y),w2(y),r3(y),w3(z),r1(x),w1(x) ,w3(y),w3(z),r2(x),r1(y), w1(y),w2(x)Which of the following is true about above schedule S.a)The schedule is serializable as T2, T3, T1b)The schedule is serializable as T2, T1, T3c)The schedule is serializable as T3, T2, T1d)The schedule is not serializableCorrect answer is option 'D'. Can you explain this answer? for GATE 2024 is part of GATE preparation. The Question and answers have been prepared according to the GATE exam syllabus. Information about Consider the following schedule:S: r2(z),r2(y),w2(y),r3(y),w3(z),r1(x),w1(x) ,w3(y),w3(z),r2(x),r1(y), w1(y),w2(x)Which of the following is true about above schedule S.a)The schedule is serializable as T2, T3, T1b)The schedule is serializable as T2, T1, T3c)The schedule is serializable as T3, T2, T1d)The schedule is not serializableCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for GATE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Consider the following schedule:S: r2(z),r2(y),w2(y),r3(y),w3(z),r1(x),w1(x) ,w3(y),w3(z),r2(x),r1(y), w1(y),w2(x)Which of the following is true about above schedule S.a)The schedule is serializable as T2, T3, T1b)The schedule is serializable as T2, T1, T3c)The schedule is serializable as T3, T2, T1d)The schedule is not serializableCorrect answer is option 'D'. Can you explain this answer?.
Solutions for Consider the following schedule:S: r2(z),r2(y),w2(y),r3(y),w3(z),r1(x),w1(x) ,w3(y),w3(z),r2(x),r1(y), w1(y),w2(x)Which of the following is true about above schedule S.a)The schedule is serializable as T2, T3, T1b)The schedule is serializable as T2, T1, T3c)The schedule is serializable as T3, T2, T1d)The schedule is not serializableCorrect answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for GATE. Download more important topics, notes, lectures and mock test series for GATE Exam by signing up for free.
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