An Improved Semi-join Query Optimization Algorithm

Query optimization is one of the core issues of the distributed database.In order to improve the query efficiency of the distributed database,the characteristics of the distributed data management system are analyzed and the key factors which influence the query efficiency of the distributed data management are found out,then the strategies of direct connection query and the principle and realization of semi-join query and the transmission costs are discussed.For the amount of repeat queries existing in the distributed database applications,an improved strategy for the semi-join queries was put forward.With an application example in contrast to traditional semi-join algorithm and the improved algorithm,the improved algorithm reduces the amount of data transmission,shortens the query processing time and improves the efficiency of the query.