-Advanced Database-
Consider the following transaction schedule, where time increases from top to bottom.
T1 |
T2 |
T3 |
T4 |
Read (X) |
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Read(Y) |
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Read(Z) |
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Read(Y) |
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Write(Y) |
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Write(Z) |
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Read(U) |
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Read(Y) |
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Write(Y) |
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Read(Z) |
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Write(Z) |
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Read(U) |
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Write(U) |
Answer the following questions:
-Advanced Database- Consider the following transaction schedule, where time increases from top to bottom. T1 T2...
2. Given the following three transactions T1 = r1(x); w1(y); T2 = r2(z); r2(y); w2(y); w2(x); T3 = r3(z); w3(x); r3(y); Consider the schedule S = r1(x); r3(z); r2(z); w3(x); r2(y); r3(y); w2(y); w1(y); w2(x); a. Draw the precedence graph of schedule S, and label each edge with data item(s). b. Based on the precedence graph, determine whether S is conflict serializable and justify your answer. If it is serializable, specify all possible equivalent serial schedule(s).
1. Consider the following schedule S TI T2 read(A) write(A write(A) write(A (a) Draw the precedence graph of S (b) Is schedule S serializable? If so, name one equivalent serial schedule, and prove equivalence (c) Denote by S"the schedule obtained by replacing the write(A) in T2 with read(A) in S. Is schedule S" serializable? If so, name one equivalent serial schedule and prove equivalence. Otherwise prove that it is not. (d) Denote by S"the schedule obtained by replacing the write(A)...
This comes from a class on databases (c) Transaction Processing Consider the following schedule: transaction TI Transaction T2 read(X) write(X) read(Y) write(Y) read write (Y) read (X) write read(W) write(W) read(Z) write(z) i. Is the schedule (conflict) serializable? If yes, give an equivalent serial schedule; if not, explain why not. ii. Add read-lock0, write-lock and unlock instructions to the schedule following the two-phase locking protocol. Is there deadlock present?
Consider the following transaction schedule: r1(X), r2(X), r3(X), r1(Y), w2(Z), r3(Y), w3(Z), w1(Y) This schedule is conflict-equivalent to some or all serial schedules. Determine which serial schedules it is conflict-equivalent to, and then identify a true statement from the list below. Select one: a. The schedule is conflict-equivalent to (T3, T1, T2) b. The schedule is not serial c. The schedule is conflict-equivalent to (T3, T2, T1) d. The schedule is conflict-equivalent to (T2, T3, T1) e. The schedule is...
Consider the following schedule that performs actions taken by transactions T1 and T2 on database objects A and B : T1: S(A), R(A), X(B), U(A), R(B),W(B), Commit: U(B) T2: S(B), R(B), X(A), U(B), R(A), W(A), Commit: U(A) Because Strict 2PL is using, this schedule is guaranteed to be conflict serializable. A: True B:False
For the system given in figure 3 identify if schedule 2 is conflict equivalent and view equivalent to schedule 1. Give proper reasons for you answer. Resolve the issues in schedule 2 by adopting appropriate locking scheme and apply deadlock prevention scheme to ensure prevention of deadlocks and starvation. (7) Table 2:Serial Schedule 1 T1 T2 T3 T4 T5 Read(X) Read(Z) Read(Y) Write(Z) ...
Q5: In DBMS, a graph precedence is used to test whether a schedule of concurrent transactions is conflict serializable or not. Given the following schedule S with three transactions T T3 T2 read(A) read(B) write(A) read(A) write(B) write(A) read(B) write(B) 1. Draw the precedence graph for the schedule S (5 points) 2. Check whether the schedule S conflict serializable or not (5 points] 3. Is it possible to construct a serial schedule S'which is conflict equivalent to the schedule S?...
Question 5. (20pts) (Briefly justify your answer) 1) Consider three transactions: T1, T2 and T3. Draw the precedence graph for the following schedule consisting of these three transactions and determine whether it is conflict serializable a) (5points) S: R1(X); R3(Z); W2(X); RI(Z); R3(Y); W2(Y), R3(Z), W1(Z), b) (5points) S: RI(X); R3(Z); W20x); RI(Y); R2(Y); W3(Y); R3(Z); WI(Z);
Consider the following schedule that performs actions taken by transactions 71 and T2 on database objects A and B: T1: R(A), WA), RIC), W(B), Commit R(B), W(B), Commit The above schedule results in an) T2: OA cascading aborts OB write-read conflict write-write conflict OD read-write Conflict
1. What is the difference between Two-Phase Locking (2PL) and Strict Two-Phase Locking? What condition to Strict 2PL prevent that 2PL does not prevent? 2. What are deadlocks? What are two techniques for detecting and resolving deadlocks? 3. In the figure below, R(X, y) means read database item X into variable y and W(X, y) means write variable y into database item y. Column T1 shows transaction T1's operations and column T2 shows T2's operations. Columns Aand_B show the values...