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1 votes
1 votes
check whether it is view serializable or not?

schedule S:R1(X),W2(X),W1(X)

7 Answers

Best answer
12 votes
12 votes
no it is not view serializable..
reason is there may b 2 schedule possible :
1. T1--->T2
2. T2----->T1z
 in case 1 final write of x is done by T2, but in given question final write of x is done by T1. so it violates condition of view serializability.
in case 2 initial read of T1 is updated value by T2 but in original question it is directly reads database.. again condition of view serialization failed..

so not serializable schedule..
edited by
1 votes
1 votes
This is definitely not CS as the precedence graph bears cycle.

This schedule is VS,as when we try to draw the view serializable graph ,we find no loops.
1 votes
1 votes
schedule will be view serializable if 1. it is conflict  serializable then surly its vs.

                                                    2. if is not cs than we have to check blind write . if there is blind write then it may be or may not be vs. for that we have to draw poly graph . if there is cycle in the poly graph we can say its not vs other wise it is vs.or not serializable schedule also.

so this schedule is vs bcoz there is no cycle in poly graph.

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