Big Data Systems HPI

Quiz 0 Distributed Systems


Question

Consider the following three transactions:

  • T1: R(A); R(B); W(C);
  • T2: R(A); R(B); W(A); W(B);
  • T3: R(C); R(B); W(C);

Which of the listed schedules is compatible with the 2PL protocol.

  1. R2(A); R1(A); R2(B); W2(A); W2(B); R1(B); C2; W1(C); C1
  2. R2(A); R1(A); R2(B); R1(B); R3(C); W1(C); R3(B); W2(A); C1; W2(B); C2; W3(C); C3
  3. R1(A); R2(A); R2(B); W2(A); R1(B); W2(B); R3(C); C2; W1(C); C1; R3(B); W3(C); C3
  4. R1(A); R2(A); R2(B); W2(A); R1(B); W2(B); W1(C); C1; R3(C); C2; R3(B); W3(C); C3

Answer
  1. R1(A); R2(A); R2(B); W2(A); R1(B); W2(B); W1(C); C1; R3(C); C2; R3(B); W3(C); C3



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