CS542 Distributed Database Systems
Prof. Bharat Bhargava

Assignment 2

Each question carries 10 points. This assignment is due on February 5, 2015.

Q1:  Comment on the suitability of using variations of:  (a) locking, (b) time stamps, and (c) versions  for concurrency control. You may use examples.

Q2: What are the different ideas for increasing the degree of concurrency? You may give examples.

Q3: What do we mean by adaptability in transaction processing? Can you switch between timestamp and locking based algorithms?  What transformations are needed? You may give examples. You may read the following paper:  A Model for Adaptable Systems for Transaction Processing, Bharat Bhargava and John Riedl, IEEE Transactions on Knowledge and Data Engineering, 1(4), Dec 1989.

Q4: How can we ensure mutual consistency if we use centralized control and issue updates to all sites after the transaction has been committed at the central site? What ideas can be used to reduce waiting at other sites?