| Network of Workstations (NOW) has increasingly become a viable, flexible yet inexpensive platform for parallel/distributed computing. Database query processing is one such area that can benefit from the use of this platform. In this thesis, a general overview of the NOW research is presented. A study has been conducted to quantify the performance difference of three predominant architectures in NOW environment, namely, centralized, distributed and hierarchical architectures, to process queries directed to a centralized database. Simulations have been performed to simulate the environment of multiple computers (PC or workstations) interconnected with a centralized database via a general-purpose communication network such as LAN. Results indicate that parallel query processing utilizing NOW exhibits good scaleup and speedup. Most importantly, all three architectures demonstrate performance sensitivity to fragmentation size. With the ideal fragmentation size used in all three architectures, however, hierarchical architecture consistently outperforms centralized and distributed architectures. |
