retagged by
70,758 views
150 votes
150 votes
Two transactions $T_1$ and $T_2$ are given as

$T_1:r_1(X)w_1(X)r_1(Y)w_1(Y)$

$T_2:r_2(Y)w_2(Y)r_2(Z)w_2(Z)$

where $r_i(V)$ denotes a $\textit{read}$ operation by transaction $T_i$ on a variable $V$ and $w_i(V)$ denotes a $\textit{write}$ operation by transaction $T_i$ on a variable $V$. The total number of conflict serializable schedules that can be formed by $T_1$ and $T_2$ is ______
retagged by

18 Answers

0 votes
0 votes
No. of conflict serializable = total schedule - no. of non conflict schedule
 
Total schedule = (m+n)!/m!n! = (4+4)!/4!4! = 70 ,here m and n  is no. of operations in t1 and t2

now no. of non conflict schedule can be calculated as:
  
                          T1:            
                                      pos1                         
                    R1(X)
                                       pos2
                    W1(X)
                                        pos3
                     R1(Y)
                                        pos 4
                     W1(Y)
                                       pos 5
For non conflict pair,R2(Y) can place at pos 1 or 2 or 3 or 4 and for W2(Y) ,it must place at either pos(4) or pos(5)
means for one position of R2(Y) there is two choices for W2(Y) ,then total combination for non conflict pair possible = 2 * 2 *2*2=16
then total conflict shedule = 70 - 16 =54. Answer
Answer:

Related questions

31 votes
31 votes
5 answers
1
Madhav asked Feb 14, 2017
10,827 views
In a B+ Tree , if the search-key value is $8$ bytes long , the block size is $512$ bytes and the pointer size is $2\;\text{B}$ , then the maximum order of the B+ Tree is ...
44 votes
44 votes
3 answers
2
Arjun asked Feb 14, 2017
16,031 views
Consider the following database table named $\text{top_scorer}$.$$\overset{\text{top_scorer}}{\begin{array}{|c|c|c|}\hline\\\textbf{player}& \textbf{country}& \textbf...
62 votes
62 votes
6 answers
3
Madhav asked Feb 14, 2017
18,239 views
Consider the following tables $T1$ and $T2.$$$\overset{T1}{\begin{array}{|c|c|c|} \hline \textbf {P} & \textbf {Q} \\\hline \text {2} & \text{2 }\\\hline \text{3} & \te...