Problem 9 - Olympiad

A multi-version system uses timestamp ordering with MVTO. Transaction T (TS=50) wants to read object O whose current version is WTS=60 and RTS=55. What action does MVTO take and what timestamp is assigned to the new read version?

Correct: N/A

MVTO allows a read only if TS(T) ≥ WTS(O). Here 50 < 60 so the read is invalid. MVTO therefore aborts T and no read version is created.