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).
2. Given the following three transactions T1 = r1(x); w1(y); T2 = r2(z); r2(y); w2(y); w2(x); T3 ...
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...
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);
You are given with the following schedule, that consists of three transactions (T1, T2, T3) and three database elements (A, B and C) w3(A); r1(A); w1(B); r2(B); w2(C); r3(C) a) Identify all the conflicts (as defined in Section 18.2.1 in the book). Hint: draw a bipartite graph between transactions and elements, as done in class b) Draw a precedence graph (as defined in Section 18.2.2 in the book). Is the schedule conflictserializable? Justify your answer
Consider the following order of operation requests from transactions T1. T2. T3 r1 (A) r2 (A) r3 (A) r1 (B) r2 (B) w1 (B) w2 (A) Show the resulting schedule table when we have a scheduler that supports shared exclusive, and update locks.
For each of the following schedules, draw the precedence graph and argue if the schedule is con ict serializable. If the schedule is con ict serializable, give one possible equivalent serial schedule. (Ri means transaction i reads an item and Wi writes an item.) a) R1(A);W1(A);R2(A);R2(B);W3(B);W2(C);R4(A);R4(B);R4(C);R2(D);R3(E);W1(E); b) R1(A);R4(A);W1(A);W3(B);R2(A);R2(B);R4(B);R4(C);R2(D);R3(E)
-Advanced Database- Consider the following transaction schedule, where time increases from top to bottom. T1 T2 T3 T4 Read (X) Read(Y) Read(Z) Read(Y) Write(Y) Write(Z) Read(U) Read(Y) Write(Y) Read(Z) Write(Z) Read(U) Write(U) Answer the following questions: Draw the precedence graph of the above schedule. Is this schedule conflict serializable? If yes, show what serial schedule(s) it is equivalent to. If not, explain why. Is this schedule view serializable? If yes, show what serial schedule(s) it is equivalent to. If not,...
9) Compute T30T20T1(x, y) for T1 (x,y)=(-2y,3x,x-2y) T2(x,y,z)=(y,z,x) T3(x,y,z)=(x +z,y-z)
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) ...
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...
2. Let Wi-((a, b, c) : a-c-b), W2-((a, b, c) : ab>0), W3-((z, y,z) : r2+92+22£1} be subsets of R3 (a) Determine which of these subsets is a subspace of R3. Justify your answer. (b) For the subsets which are subspaces, find a basis and the dimension for each of them 2. Let Wi-((a, b, c) : a-c-b), W2-((a, b, c) : ab>0), W3-((z, y,z) : r2+92+22£1} be subsets of R3 (a) Determine which of these subsets is a subspace...