Concurrent schedule means non-serial schedule.

what is the answer?

0 votes

how to find total number of concurrent schedule possible when any schedule is given ?

for example consider this schedule

**T1 : R1(A) , W1(A) , R1(B) , W1(B) ;**

**T2 : R2(A) , W2(A) , R2(B) , W2(B) ;**

0

There are in total 12 ways..i have divided into 4 sets of RW and in each case there are 3 possiblities in positioning 2&3.

if we break R() W() of same data item then the graph will lose it's serializability. so W of a data item on any transaction should be executed right after the R of the same data item on the same transaction.

**concurrent 1: R1(A) , W1(A) , R2(A) , W2(A) , R1(B) , W1(B) , R2(B) , W2(B) ;**

**concurrent 2: R2(A) , W2(A) ,R1(A) , W1(A) , R1(B) , W1(B) R2(B) , W2(B) ;**

**concurrent 3: R1(A) , W1(A) , R2(A) , W2(A) , R2(B) , W2(B) R1(B) , W1(B) ; **

**concurrent 4: R2(A) , W2(A) ,R1(A) , W1(A) , R2(B) , W2(B) R1(B) , W1(B) ;**

**each one can be represented in 3 ways as shown in the image**

let me know if u need any clarification..