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Exercise 12.5 -- construct the tree where the number of pointers that will
fit in a node is 3.
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Exercise 12.6 a
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Exercise 12.7 a, b, d
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Exercise 12.12
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Exercise 12.13 a, b, d
(these numbers are from 4th edition)
Transaction Management
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For each of the following schedules below, a) show the precedence graph;
b) is the schedule conflict-serializable?; c) if so, what are the equivalent
serial schedules?
Schedule S1: r1(A); r2(A);
r3(B); w1(A); r2(C); r2(B); w2(B); w1(C);
Schedule S2: w3(A); r1(A); w1(B);
r2(B); w2(C); r3(C);
Schedule S3: r1(A); r2(A); r1(B);
r2(B); r3(A); r4(B); w1(A); w2(B);
Two-Phase locking (numbers from 4th edition)
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16.2
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16.3
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16.4
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Consider the following actions taken by transaction T1 on database objects,
X and Y: r1(x); w1(x); r1(y); w1(y)
a) Give an example of another transaction T2 that, if
run concurrently to transaction T without some form of concurrency control,
could interfere with T1 (in other words, the schedule of T1 and T2 together
will not be serializable).
b) Explain how the use of 2PL would prevent interference
between the two transactions (that is, make the schedule serializable.)