Study of optimization algorithm for semi-join query

To improve the query efficiency of the distributed data management system,the characteristics of the distributed data mana-gement 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.Finally a strategy is proposed for semi-join query with the distributed data management system as an example.The improved semi-join query strategy optimizes the join scheme,reduces the cost of data transmission,shortens the response time of query processing and raises the efficiency of query.