Optimistic Concurrency Control (cont)
Case 2: reading/validation overlaps validation/writing
- T2 starts validating while T1 is validating/writing
- if some X being written by T2 is in WS(T1)
- then T2 may end up overwriting T1's update
- so, T2 must start again
![[Diagram:Pics/txproc/occ2.png]](Pics/txproc/occ2.png)
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