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LAB 8 | Multiversion concurrency control.
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PRACTICE EXERCISES
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(1) Get familiar with the terms:
    - multiversion concurrency control,
    - multiversion timestamp ordering,
    by attending the lecture and reading chapter 15.6 from the textbook.

(2) Consider the following schedules. Indicate what happens when the schedule
    is processed by a multiversion timestamp-ordering scheduler. The
    transactions start in order with TS(T1)=1, TS(T2)=2, TS(T3)=3, TS(T4)=4.
    Assume that no versions of data item A exist. Compare the results to the
    timestamp-ordering scheduler (assume W-ts(A)=R-ts(A)=0 at start).

    Schedule 1
    -------------------------------------------
    T1:         T2:         T3:         T4:
    write(A)
                            write(A)
                                        read(A)
                read(A)

    Schedule 2
    -------------------------------------------
    T1:         T2:         T3:         T4:
    write(A)
                write(A)
                            write(A)
                read(A)
                                        read(A)

    Schedule 3
    -------------------------------------------
    T1:         T2:         T3:         T4:
    write(A)
                                        write(A)
                            read(A)
                write(A)


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HOMEWORK
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No homework.