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CS157b Spring 2005Practice FinalTo study for the midterm I would suggest you: (1) Know how to do (by heart) all the practice problems. (2) Go over your notes three times. Second and third time try to see how huch you can remember from the first time. (3) Go over the homework problems. (4) Try to create your own problems similar to the ones I have given and solve them. (5) Skim the relevant sections from the book. (6) If you want to study in groups, at this point you are ready to quiz each other. The practice final is below. Here are some facts about the actual final: (a) The final will be in class May 23, 9:45am-12:00pm (Sec 1) and May 20, 12:15pm-2:30pm (Sec 2). (b) It is closed book, closed notes. Nothing will be permitted on your desk except your pen (pencil) and test. (c) You should bring photo ID. (d) There will be more than one version of the test. Each version will be of comparable difficulty. (e) If your cell-phone or beeper goes off you will be excused from the test at that point and graded on what you have done till your excusal. (f) One problem (less typos) on the actual test will be from the practice test. Student Generated Solutions-PDF. 1. Imagine the partial log file (START T), (T, X, 3), (START S), (S, Y, 1), (T, Y, 4), (COMMIT S), crash. Suppose undo logging was being used. What elements would have had there values stored on disk? What would be undone during recovery? 2. Suppose we are using checkpointing. How far back in the log file do we need to look for each of the following logging methods during the recovery process: (a) undo logging, (b) redo logging, (c) undo/redo logging. 3. Give an example of what a log file might look like during a non-quiescent dump. Explain the steps that must be happening during the dump. 4. Give separate examples of each of the following: (a) a serializable schedule which is not conflict serializable (b) a schedule that is not serialiazable (c) a schedule which not realizable using two-phase locking but is realizable using timestamp ordering. 5. Draw the precedence graph for the following schedule: W_1(X), R_2(Y), W_3(X), R_2(X). 6. Explain how intensional share and intensional exclusive locks are used. 7. What are updates locks? Draw a compatibility matrix for the situation where we are using share, update, and exclusive locks. 8. What are increment locks? Draw a compatibility matrix for the situation where we are using share, increment, and exclusive locks. 9. What is a phantom tuple? What is a dirty read? How are they connected to isolation levels? 10. Briefly describe under what condition a transaction has to wait if we are using basic timestamping for concurrency control. |