#view-serializability

Question

Is this schedule view serializable?

S: R1(A) R2(A) W1(A) W2(A) R1(B) R2(B) W1(B) W2(B)

Comments

It is a view serializable schedule
It is view equivalent to serial schedule T1---->T2

 

Answer 1

Yes, this Schedule is View Serializable.

Answer 2

No

This schedule is not conflict serializable as the precedence graph shows a cycle and there is no blind write so it is also not a view serializable.

 

Comments

I think it is a view serializable, although it is not conflict serializable and it does not have blind write. It follows conditions for the view serializable.

Answer 3

This is a view serializable schedule bacause,

Step 1. It is not a conflict serialiable, because it produces a cyclic graph.

Therefore, it could be view serializable or not.

Step 2. It does not have blind write

Therefore, it could be view serializable.

Step 3. Check for the view serializable conditions:

• Inital Read is same for both transactions
• Final Transactions match
• Read-Write Relationship does not match can be deduced from dependency graph.

Therefor this is a View Serializable.

Answer 4

NO , This cannot be view serializable . Neither is it conflict serializable .

For the answers mentioned above , if we scheudle T1 -> T2 , then the view for R2(A) changes . Earlier while executing concurrently it was NOT reading from W1(A) while here in serial schedule it is , which shows , it is NOT view equivalent