Design of distributed database systems: an iterative genetic algorithm

摘要

The two important aspects for design of distributed database systems are operation allocation and data allocation. Operation allocation refers to query execution plan indicating which operations (subqueries) should be allocated to which sites in a computer network, so that query processing costs are minimized. Data allocation is to allocate relations to sites so that the performance of distributed database are improved. In this research, we developed a solution technique for operation allocation and data allocation problem, using three objective functions: total time minimization or response time minimization, and the combination of total time and response time minimization. We formulated these allocation problems and provided analytical cost models for each objective function. Since the problem is NP-hard, we proposed a heuristic solution based on genetic algorithm (GA). Comparison of results with the exhaustive enumeration indicated that GA produced optimal solutions in all cases in much less time.