Research On Query Optimization Of Database Management System

Nowadays, the information technology is developing very fast. Database has been a basical and necessary instrument for managing or excavating greatness potential of information. With the time is passing, the amount of data goes increasingly, as a result, one of the most important characters of database is potence of maintaining the performance. The primary mechanism of holding the performance of database on the best level has been named the query optimizer of database.Without a favourable query optimizer, even if a minitype database behaves remarkable low performance. At present, many commercial databases have showed various degrees of realizing the function of query optimization. Because of designing an actural query optimizer is unconventionally complex, usual query optimizers of commercial databases require at least fifty person/year workload. In this paper, we emphasize particularly on academic research. We have studied the technology of query optimization in relational databases, contrasted the virtue and disadvantage of all kinds of current technology, present a model of the based-statistical query optimizer which can be fit for the SECBase. We also take aim at the problem of the efficiency of many-join-query, present an improved Genetic Algorithm. In addition, we make some key discussions on realization of query optimization. By some tests, we proved that the model of the based-statistical query optimizer is feasible, the improved GA has obviousadvantages in the process of dealing with many-join-query.