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Homework 5 for CSC691D: Advanced Database Management

You are allowed to collaborate for this homework. Form teams of 1-3 students. Each member of the team must work on every problem. Mention the names of your partners on your homework.
  1. (20 points) What is the smallest number of global and local transactions that is required for there to be a violation of global serializability due to indirect conflicts. The example in Breitbart et al. involves 2 global and 2 local transactions.
  2. (20 points) What is the smallest number of global and local transactions that is required for there to be a deadlock that cannot by detected by the GTM or any individual LDB.
  3. (25 points) An approach such as tickets achieves global serializability, but by causing conflicts to abort lots of transactions. Suppose there are g global transactions, each executing at the same s sites. Suppose these transactions are started concurrently and executed in random interleavings at the s sites. What is the probability n of these transactions will commit (assuming aborts happen only because of ticketing violations)? Make any additional assumptions if necessary. What does that say about the practicality of ticketing when g, s, and n are all equal to 3.
  4. (25 points) Following up on the spheres of control you identified in HW4 (for the conference trip and house purchase), describe them in the approach of Nodine & Zdonik. Show how the schedule might be enacted. Make any additional assumptions if necessary.
singh@ncsu.edu