單項(xiàng)選擇題
T1,T2,T3三個(gè)事務(wù),記wi(A)為事務(wù)Ti寫數(shù)據(jù)對(duì)象A,ri(A)為事務(wù)Ti讀數(shù)據(jù)對(duì)象A,有兩個(gè)調(diào)度S1和S2為:
S1:r2(A);r1(B);w2(A);r2(B);r3(A);w1(B);w3(A);w2(B)
S2:r2(A);r1(B);w2(A);r3(A);w1(B);w3(A);r2(B);w2(B)
關(guān)于S1和S2,說法正確的是()。