Homework (1) Question1: Consider the following schedule S of transactions T1, T2, T3 and T4. S=R2(Y); R2(X); C3; Wi(X); W2(Y); R (Z); C2; R4(X); R4(Y); Wi(Z); C1; C4; Find out which of the following statements are true (T) or false (F). Justify your answer. S is conflict serializable S is recoverable S is cascadeless schedule a) i-T, ii-T, iii-F b) i-T, ii-F, iii-F c) i-F, ii-T, 111-T d) i-T, ii-F, 111-T Question 2: Does the following partial schedule S obey two phase locking? If it does not, change it to obey two phase locking. T1 T2 Lock-X(B) Read(B) Write (B) Lock-X(A) Lock-S(A) Read(A) Unlock(A) Lock-S(B) Read(B) Unlock(B) Unlock(B) Read(A) Write(A) Unlock(A) Question 3: Given the following log: [Start Ti] [T1, B, 20, 25] [Start T2] [check point] [T2, C, 70, 60] [T2 Commit] [Start T3] [T3, A, 50, 40] 1. Which transaction IDs are in the undo list and which are in the redo list? 2. What are the values of A, B, and C after the algorithm has finished assume that the log entry is written as [Tid, Item, Old value, New value]? Question 4: 1. Provide an example for dirty read (temporary update) problem? 2. What is meant by term well-formed transaction