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Subject Database Management Systems (CO3021) Semester 1, 2020 2021 1 Chapter 5 Introduction to Transaction Processing Concepts and Theory Question 5 1 Differentiate multiuser systems from single user[.]
Subject: Database Management Systems (CO3021) Semester 1, 2020-2021 Chapter 5: Introduction to Transaction Processing Concepts and Theory Question 5.1 Differentiate multiuser systems from single-user systems Give their examples Question 5.2 Describe different types of failures and give their examples Question 5.3 What is a transaction? Give examples Question 5.4 Discuss the ACID properties of a transaction Question 5.5 What is a system log? What records are stored in the log? Write the content of the log for your transactions in Question 5.3 Question 5.6 What is a commit point? Give an example Question 5.7 What is a schedule? Give an example Question 5.8 Given the following transactions: T1: r1(X); r1(Z); w1(X); c1; T2: r2(Z); r2(Y); w2(Z); w2(Y); c2; T3: r3(X); r3(Y); w3(Y); c3; What are valid schedules? Write their log contents S1: r1(X); r1(Z); r3(X); r3(Y); w1(X); w3(Y); c1; c3; S2: r2(Z); r3(X); r2(Y); r3(Y); w2(Z); w3(Y); w2(Y); a3; c2; S3: r2(Z); r1(X); r1(Z); w2(Z); w1(X); r2(Y); w2(Y); c2; c1; S4: r1(X); r3(Y); r1(Z); w3(Y); w1(X); c1; r3(X); c3; Question 5.9 What are recoverable schedules? What are cascadeless schedules? What are strict schedules? Question 5.10 What is the recoverability characteristic of each following schedule? S5: r1(X); r2(Z); r1(Z); r3(X); r3(Y); w1(X); c1; w3(Y); c3; r2(Y); w2(Z); w2(Y); c2; S6: r1(X); r2(Z); r1(Z); r3(X); r3(Y); w1(X); w3(Y); r2(Y); w2(Z); w2(Y); c1; c2; c3; S7: r1(X); r2(Z); r3(X); r1(Z); r2(Y); r3(Y); w1(X); c1; w2(Z); w3(Y); w2(Y); c3; c2; S8: r1(A); r2(B); w1(B); c1; w2(C); c2; r3(B); r3(C); w3(D); c3; S9: r1(A); w1(B); c1; r2(B); w2(C); c2; r3(C); w3(D); c3; S10: r2(A); r3(A); r1(A); w1(B); c1; r2(B); r3(B); w2(C); c2; r3(C); c3; S11: r2(A); r3(A); r1(A); w1(B); r3(B); w2(C); r3(C); a1; a2; a3; Question 5.11 What are conflict-serializable schedules? Give an example Question 5.12 What is the conflict-serializable characteristic of each following schedule? Draw their precedence graphs Determine their equivalent serial schedules S12: r1(X); r3(X); w1(X); r2(X); w3(X); S13: r1(X); r3(X); w3(X); w1(X); r2(X); S14: r3(X); r2(X); w3(X); r1(X); w1(X); S15: r3(X); r2(X); r1(X); w3(X); w1(X); S16: r1(X); r2(Z); r1(Z); r3(X); r3(Y); w1(X); w3(Y); r2(Y); w2(Z); w2(Y); S17: r1(X); r2(Z); r3(X); r1(Z); r2(Y); r3(Y); w1(X); w2(Z); w3(Y); w2(Y); S18: r2(X); r1(X); r3(Y); w3(Y); r1(Y); w2(X); w1(X); w1(Y); S19: r1(Z); r1(X): r2(Y); w2(Y); r3(X); r2(Z); w1(Z); w1(X); r2(X); w3(X); w2(X); S20: r1(X); w1(X); r2(Y); r2(X); w2(Y); r1(Y); w2(X); r3(Y); w1(Y); r3(X); w3(X); w2(Y); w3(Y); Question 5.13 Given two following transactions: T4: r4(A); w4(A); r4(B);w4(B); T5: r5(A); w5(A); r5(B);w5(B); Prove that the schedule S21 is conflict-serializable: S21: r4(A); w4(A); r5(A); w5(A); r4(B);w4(B); r5(B);w5(B) (Hint: reordering the nonconflicting operations in S21 until we form the equivalent serial schedule) Question 5.14 Consider the three transactions T6, T7, and T8, and the schedules S22 and S23 given below Draw the serializability graph for S22 and S23, and state whether each schedule is conflict-serializable or not If a schedule is conflict-serializable, write down the equivalent serial schedule T6: r6(B); w6(B); T7: r7(A); w7(A); r7(B); w7(B); T8: r8(A); w8(A); S22: r7(A); r6(B); w7(A); r8(A); w6(B); w8(A); r7(B); w7(B); S23: r7(A); r6(B); w7(A); r7(B); r8(A); w6(B); w8(A); w7(B);