View Serializability Doubt Question (Difficulty Level 5/5) 5 Transactions and 5 Data Items

[@surprise_notsofast]

Thanks!!! Cleared my doubt about view serializability. Hopefully nobody would ask such question for GATE

[@ritukapurclasses1591]

Thank you for your appreciation. Nd once you get a hold on basics, if attempted carefully, you can easily get through any kind of question. Though attempting max. correct in exam pressure nd under time constraint is something one needs to practice. Thus, practice as much as possible.

[@rohitbale15]

Mam it is indeed a conflict serializable schedule. We can directly see it by building the precedence graph. The only execution schedule possible is T1->T2->T3->T4->T5. May be other execution orders possible but the order i have mentioned is for Conflict serializability hence view serializable schedule as well.

[@abhaynanda1117]

Mam you are simply awesome. Great videos. Keep up the great work. You are helping the students in the best way possible.

[@ritukapurclasses1591]

+abhay nanda thnku :)

[@abhijithowal9025]

Great work ritu.. I was really confused about view Serializability.. But your videos cleared all my doubts.. Thanks alot..

[@ritukapurclasses1591]

+Abhijit Howal thank you... Means a lot...

[@abhijithowal9025]

Ritu Kapur Classes you are welcome.. keep doing the great work..!!👍👍

[@sagarlodhiya5537]

I think you missed Two conflicts : 1) W1(B) -> W3(B) [Since it is already included in other we can skip this] 2: W3(B) -> R4(B) i.e :-> T3->T4. there should be 7 constraint instead of 6. please check it one more time. Thanks

[@ritukapurclasses1591]

+SAGAR LODHIYA Thank you for the correction. So, we have the only possible answer as T1: T2: T3: T4: T5

[@ritukapurclasses1591]

+SAGAR LODHIYA we won't consider W1->W3 case since we are only checking for RW pairs

[@sagarlodhiya5537]

T1->T2->T3 is the serial schedule for given schedule. In order to find out whether the given schedule is view serializable or not first we need to check the given schedule is conflict serialiable or not . If given schedule is conflict serializable then we can directly say that the given schedule is view serializable . if given schedule is not conflict then we need to check whether the schedule is having blind write or not. in above example there is a blind write of T2 hence, we need to check for view serializability.

[@ritukapurclasses1591]

+prakrati gupta The Answer is that it is not view serializable... Solving method is same... when u form the table, you get the following Initial Read: T1 Update: T1, T2, T3 Final Update: T3 So the order should be: T1:T2: T3 but if you check the read-write sequence with this schedule, there is a violation as the order of R3(a) and W1(a) gets changed... Therefore, no view serializable order is possible... please let me know, if it is still not clear and i'll explain it in a video session ... Hope it was of sm help ... Happy Learning :)

[@muskanpritam6147]

THANK YOU SOO MUCHHHHH...THIS REALLY HELPED ME...

[@ritukapurclasses1591]

Glad it helped!

[@Gamechanger..601]

Mam awesome explanation.. cant we just solve this question with precedence graph???

[@KARTHIK2059]

r6(x),w4(y),r6(y),w2(t),r4(w),r1(x),w6(t),w1(x),w3(y),w4(w),w5(t),w4(y),r4(x) Hello, Ritu can you help me in solving this to check whether it is VSR or not.?

[@aryan_kode]

how did you do read write analysis ??

[@shourabhpayal1198]

Hi very well explained. I think you missed t1->t2->t4->t3->t5

[@jappreetsingh8177]

which book do you use for DBMS?

[@sumitgoyal385]

thanks and happy :) new year

[@ritukapurclasses1591]

+sumit goyal Happy New Year to u too :)