Question 8416 – Transactions
January 4, 2024Transactions
January 4, 2024Transactions
Question 19

Consider the following four schedules due to three transactions (indicated by the subscript) using read and write on a data item x, denoted by r(x) and w(x) respectively. Which one of them is conflict serializable?
r_{1} (x); r_{2} (x); w_{1} (x); r_{3} (x); w_{2} (x)


r_{2} (x);r_{1} (x);w_{2} (x);r_{3} (x);w_{1} (x)


r_{3} (x);r_{2} (x);r_{1} (x);w_{2} (x);w_{1} (x)


r_{2} (x);w_{2} (x);r_{3} (x);r_{1} (x);w_{1} (x)

Question 19 Explanation:
Option: A
– Polygraph contains cycle. So, not a conflict serializable.
Option: B
Cyclic
Option: C
– Cyclic
Option: D
– Acyclic, so conflict serializable.
– Polygraph contains cycle. So, not a conflict serializable.
Option: B
Cyclic
Option: C
– Cyclic
Option: D
– Acyclic, so conflict serializable.
Correct Answer: D
Question 19 Explanation:
Option: A
– Polygraph contains cycle. So, not a conflict serializable.
Option: B
Cyclic
Option: C
– Cyclic
Option: D
– Acyclic, so conflict serializable.
– Polygraph contains cycle. So, not a conflict serializable.
Option: B
Cyclic
Option: C
– Cyclic
Option: D
– Acyclic, so conflict serializable.
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