serial schedule

Question

Ques2:how many serial schedule view equal to schedule (s)?

Answer 1

1. Conflict equal serial schedules
Conflict pairs: T1->T2, T1->T5, T1->T4, T2->T5,T4->T5
T1->T2->T4->T5, Put T3 anywhere, 5 places.
T1->T2->T4->T5, Put T3 anywhere, 5 places
Hence, total 10 equal conflict serial schedules.

2. View equal serial schedules
Following are the dependencies
W/R Sequences
T1->T2
T1->T4
T4->T5
Last Updated By
T1->T5
Now, T1->(T2,T4,T5) and T4->T5
T1->T2->T4->T5, Put T3 anywhere, 5 places.
T1->T2->T4->T5, Put T3 anywhere, 5 places
Hence, 10 view equal serial schedules are possible.

Comments

T1->T4 has WR conflict, which is to be preserved in every view equivalent schedule.

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@ joshi_nitish

initial B is reading by the T2  and then T4 ...so i think T2 comes before T4

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I am also getting 10 view equal serial schedules, and updated my solution!

Answer 2

T1	T2	T3	T4	T5
r1(A)
		r3(D)
w1(B)
	r2(B)
			r4(B)
	w2(C)
				r5(C)
			w4(E)
				r5(E)
				w5(B)

Conflict operations sequence is 

T1--->T2  and T1--->T4 on B

T2--->T5 on C

T4--->T5 on B and E

Combining all precedence graph would look like

so Answer is option B(15)

View Serializable Answer

Total no of view serializable schedule is 8

Comments

for B you forget t1- t5 i,e. final write on B

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I have answered only for conflict serializability

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i am saying about conflict sealizability only. final write on B means t1 to t5 arrow come beacause in t5 at last WB present, you forget to take it

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No, you have to consider conflicting operation from the last read or write. in this case, it was last read by T4

Answer 3

10 serial schedule are conflict equal.