self doubt(conflict serializable)

Question

Q.1 find total number of conflict serializable

T1=R(A)W(A)R(B)W(B)

T2=R(B)W(B)R(C)W(C)

Q.2 find total number of conflict serializable for

T1=R1(A)W1(A)R1(B)W1(B)R1(C)W1(C)

T2=R2(A)W2(A)R2(B)W2(B)R2(C)W2(C).

explanation??.

Comments

https://gateoverflow.in/118640/gate2017-2-44

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Actually, the answer provided in GATE-2017 question, didn't satisfy me.

I did with my approach, you may check it.

@BASANT KUMAR

Don't add two different questions, in one post from next time.

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@shaikh thnxx ver much for uploading these images

thesereally helped me

Answer 1

NEW APPROACH :-

For question 1 :-

see my answer at https://gateoverflow.in/118640/gate2017-2-44?show=289691#a289691

For question 2:-

Before coming to question 2, please understand the procedure which is used in the Q1, due to it is same concept

For clarity images :- https://drive.google.com/open?id=1dka-cqVm6ZppPI81Mm9WztqV_pG5iMMh

Recommended to see the same type of question  https://gateoverflow.in/272638/total-conflict-serializable-schedules

 

OLD APPROACH :-

For Question 1 :-

For clarity images https://drive.google.com/open?id=1o12YFKd8JLhlXWLB1D3tuph91ENJ0OCd

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For Question 2 :-

For Case 3 and Case 4 :-

Note that R2(B) should be after W1(B)

Comments

i have calculated for T1-T2-T3 it came out to be 3 similarly for T1-T3-T2. i have a doubt, how many other ordering do we have to consider? like all the others, as i am getting the wrong answer.

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I suggest you to post a new question with all the details along with your doubt.

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Doubt:- 1. No. of transaction is 3 hence 3! serial schedule, do we have to check conflicts in all 6 schedule? 

2.  for 2 transaction this approach is doable in exam, is there any other method apart from this one:👇

   Total no. of concurrent schedule= (2+2+2)!/2!2!2!=90

conflict equivalent schedule= 90/6=15.      why this method work only for certain question?

3. like this question(asking for conflict equivalent) S : w₁(A) w₁(B) r₂(A) w₂(B) r₃(A) w₃(B)  I'm getting 15 again(am i doing anything wrong here?)

ques link: https://gateoverflow.in/115201/number-of-schedules-conflict-equivalent-schedule?show=115220