CS245 Winter 2009 Final Solutions 


1. 
(a) T
(b) F
(c) T
(d) F
(e) F
(f) F
(g) T
(h) T
(i) T
(j) T

2. 
(a) x, 5 IOs (4 IOs just for index)
(b) y, 5 IOs (4 IOs just for index)
(c) 23 IOs (13 IOs just for index) 

3. 
(a) B<-9, A<-4
<ABORT T1>, <ABORT T2>, FLUSH LOG
(b) A<-4, B<-10
<ABORT T1>, FLUSH LOG 
(c) C<-14, A<-4
<ABORT T1>, <ABORT T3>, FLUSH LOG
(d) C<-15
(none)

4. 
(a) 
r1(A) w1(B) c1 w2(A) r2(B) c2
r1(A) w1(B) w2(A) c1 r2(B) c2
r1(A) w1(B) w2(A) r2(B) c1 c2
r1(A) w1(B) w2(A) r2(B) c2 c1
r1(A) w2(A) w1(B) c1 r2(B) c2
r1(A) w2(A) w1(B) r2(B) c1 c2
r1(A) w2(A) w1(B) r2(B) c2 c1
w2(A) r1(A) w1(B) c1 r2(B) c2
w2(A) r1(A) w1(B) r2(B) c1 c2
w2(A) r1(A) w1(B) r2(B) c2 c1

(b) 5
(c) 3
(d) 3
(e) 7 

5. 
(a) 15000 IOs
(b) 75000 IOs
(c) 35000 IOs
(d) 25000 IOs
(e) 260000 IOs

6. 
(a) 
A: 50
B: 5
C: 2
D: 20

(b) R(*,B,C,D), 1
(c) R(A,B,*,*), 0
(d) R(*,B,C,D), 19
(e) R(*,B,C,D), 39 

7. 
(a) Yes
T1T2T3T4 or T1T2T4T3
Yes
l-X1(Y) w1(Y) l-X2(X) w2(X) l-S2(Y) u2(X) l-S3(X) r3(X) l-S1(Z) r1(Z) l-X4(Z) w4(Z) l-S4(X) r4(X) r2(Y) u1(Y) u2(Y) u3(X) u1(Z) u4(Z) u4(X)

(b) No
(none)
No (not conflict serializable) 

8. 
(a) All allowed
All allowed
(b) All allowed
A,B
(c) All allowed
A,B
(d) All allowed
A,B,C