Description

1) For each of the following schedules, state which of the following properties hold: conflict serializable, recoverable, cascadeless, or strict.
Note that a conflict serializable schedule is one that has no conflicting operations among its committed transactions. Aborted transactions are ignored when determining conflict serializability.
a) R1(A) W1(B) R2(B) W2(A) W1(A) Commit T1 Commit T2
b) W1(A) R2(A) W1(A) Commit T2 Abort T1
c) W3(A) R2(A) Commit T3 W1(B) Commit T1 R2(B) W2(C) Commit T2
d) W1(A) R1(B) R2(B) Commit T1 R2(A) W2(B) Commit T2
e) W1(A) R2(B) R1(B) R2(A) Commit T1 Commit T2

2) Consider the following schedule:
R1(A) W1(A) R2(A) W2(A) R2(B) W2(B) T2:Commit, T1:Abort
Is this schedule allowed by Two Phase Locking? If not explain why. If so, show the schedule with lock requests and releases obeying 2PL.

3) Consider the same schedule:
R1(A) W1(A) R2(A) W2(A) R2(B) W2(B) T2:Commit, T1:Abort
Is this schedule allowed by Strict Two Phase Locking? If not explain why. If so, show the schedule with lock requests obeying Strict 2PL.

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