Transaction Processing Study Guide and

Homework 5

CSE444

You should be able to do all of the following problems for the final exam. So, you can use this as a study guide to test your understanding of transaction processing.

To Turn In: Select 3 of the 8 problems to write up and turn in for the final homework.

Due: Wednesday, December 10

  1. Find all conflicts in the following schedule:

    2. S: r2(X); r1(X); w1(X); r1(Y); w2(X); c2; w1(Y); c1;

     

  2. In the following schedule, tell which transactions read from other transactions:

    3. S: r1(X); r2(Y); w1(X); r3(X); w2(Y); c2; w3(X); c3; r1(Y); w1(Y); c1;

     

    Is this schedule recoverable?

  3. Are the following 2 schedules conflict equivalent?

    4. S1: r1(X); r2(Y); w2(Y); r1(Y); w1(X); w1(Y); r2(X); w2(X); c2; c1;

    S2: r2(Y); r3(Z); w3(Z); w2(Y); r1(X); w1(X); r1(Y); w1(Y); r2(X); w2(X); c2; c1; c3;

     

  4. Is this schedule conflict serializable?

    5. S: r1(X); r2(Y); w1(X); r3(X); w2(Y); c2; w3(X); c3; r1(Y); w1(Y); c1;

     

     

     

     

  5. Does the following schedule follow the 2 phase locking protocol?

    6. T1

    T2

    Read_lock(Y)

     

    Read_item(Y)

     

    Unlock(Y)

     

     

    Read_lock(X)

     

    Write_lock(Y)

     

    Y = Y + X

     

    Write_item(Y)

     

    Unlock(Y)

     

    Unlock(X)

    Write_lock(X)

     

    Read_item(X)

    X = X * Y

     

    Write_item(X)

    Unlock(X)

     

     

  6. Give an example of a schedule with a deadlock.

    7.  

  7. Give an example of a schedule in which the basic Timestamp ordering algorithm would cause a transaction to abort.
  8. Given a schedule with locks, what technique would you use to detect deadlocks?