1. Consider the following schedule S: T1 T2 T3 T4 T5 T6

Read(C) Write(C) Read(A) Read(C) Write(A) Write(C) Write(A)

Write(C) Write(B) Read(A)

Write(A)

(a) Is S (conflict) serializable? Show your work!

(b) Is S view serializable? Show all details of your answer! 2.State which of the schedules are serializable. For each serializable schedule give an equivalent serial schedule. 1. 1. S1 = {read(T1,x), read(T2,y), read(T1,z), read(T3,z), read(T2,x), read(T1,y)} 2. S2 = {read(T1,x), write(T2,y), read(T1,z), read(T3,z), write(T2,x), read(T1,y)} 3. S3 = {read(T1,x), write(T2,y), read(T1,z), read(T3,z), write(T1,x), read(T2,y)}

4. S4 = {read(T1,x), read(T2,y), read(T1,z), read(T3,z), write(T1,x), write(T2,y)}

5. S5 = {write(T1,x), read(T2,y), read(T1,z), read(T3,z), read(T1,x), write(T2,y)} 3. Consider the transactions T1 and T2 below.

read(balance1) write(balance1) read(balance1)

read(balance2) write(balance1)

read(balance2) write(balance2)

Assume that ts(T1) = 350, and ts(T2) = 375. Use the basic timestamp ordering algorithm to trace (report timestamp values ts(T), read_timestamp(), and write_timestamp() values) the execution of each of the instructions in the transactions. Initially, read_timestamp and write_timestamp values of each data item are set to 0.

4. Draw the ER-diagram+ to represent the system described in Appendix B.2. (hand-out) of the textbook. Using the ER-diagram produce a distributed database design for the system, and include

1. A suitable fragmentation schema for the system.

2. In the case of primary horizontal fragmentation, a minimal set of predicates. 3. The reconstruction of global relations from fragments.

State any assumptions necessary to support your design.