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Optimistic Concurrency Control (cont)

Validation check for transaction T
  • for all transactions Ti  ≠  T
    • if T∈S & Ti∈F, then ok
    • if T∉V & V(Ti) < S(T) < F(Ti),
      then check WS(Ti) ∩ RS(T) is empty
    • if T∈V & V(Ti) < V(T) < F(Ti),
      then check WS(Ti) ∩ WS(T) is empty
If this check fails for any Ti, then T is rolled back.