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The following diagram was taken from a book(T1 and T2 are transactions which read and write to databases objects A and B). For convenience, I quoted few lines of text in that book which describe the diagram and the quote is below.

"Even though the actions of T1 and T2 are interleaved, the result of this schedule is equivalent to running T1(in its entirety) and then running T2. Intuitively, T1's read and write of B is not influenced by T2's actions on A, and the net effect is the same if these actions are 'swapped' to obtain the serial schedule T1;T2."

My question is regarding this "Even though the actions of T1 and T2 are interleaved, the result of this schedule is equivalent to running T1(in its entirety) and then running T2." statement. How can this be true if T2 commits before T1? Please give a detailed answer.

A serializable schedule

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If the "running T1(in its entirety) and then running T2" is understood as running the T1.commit, too, before T2 starts, does it make sense? –  ypercube Oct 12 '13 at 10:03

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