serializable schedule

Consider the following transactions with data items P and Q initialized to zero:

T1T1
read (P);   
read (Q);  
if P = 0 then Q := Q + 1 ;  
write (Q).
T2T2
read (Q);  
read (P);  
if Q = 0 then P := P + 1 ;  
write (P)

 

Any non-serial interleaving of T1 and T2 for concurrent execution leads to

(A) a serializable schedule 
(B) a schedule that is not conflict serializable 
(C) a conflict serializable schedule 
(D) a schedule for which a precedence graph cannot be drawn

2Comments
set2018 @setgate
11 Oct 2017 12:26 pm

@shivani ma'am see this pls

shivani @shivani1234
11 Oct 2017 04:18 pm

a schedule that is not conflict serializable 
as there can be schedule as like this:

T1 T2
read (P);
 
read (Q);
 
if P = 0 then Q := Q + 1 ;
 
 
read (Q);  
write (Q).
 
 
read (P); 
 
if Q = 0 then P := P + 1 ;  
write (P)