Applied Study On Query Optimization Strategy In A New Generation Of Database

Database technology is developing rapid, and it has divided into the various types which are distributed database and parallel database mainly depending on the different focus. Distributed database system is a product of the combination of database system and distributed system. It connects multiple logical units which can compose a database system with the computer network. These logical units are geographically dispersed, but they are managed and controlled on different level of concentration. Today, the query optimization to distributed database is one of the important research directions in the theory of database.The distributed and redundant storage of data makes distributed query optimization more complex. There exists much distributed query optimization algorithm. Some algorithm is based on semi-connection. Some algorithm is based on direct connection. Each method has its merits, while, inevitably flawed. In order to looking for a nearly optimal balance, it must learn from each one according to the application environments. This paper proposes a hash algorithm based on distributed database query optimization strategies.Based on the actual project of LiaoHe Oilfield Petroleum Development Company and the database query optimization technology, combined with the company's business background, this paper is to reduce the data transmission between distributed sites and cost of network communication by using Hash algorithm. Hash algorithm divided different relation tables into different parts to establish the corresponding relationship between the storage site of tuple relationship and certain attribute of this tuple. On the basis of that, we maintain the site dependency when relations execute join operation, thus the cost of data transmission has been reduced. Finally, relations are joined in parallel by multiple threads in various sites, reducing the query response time.In the end of this paper, it carried out the experiment through multiple test data. Experimental results show that the application of this query optimization strategy can make the distributed database queries more efficient. Though the production and distribution of oil mine in the comprehensive dynamic tracking system, it gives the design and implementation of distributed database query optimization techniques based on Hash algorithm. This system has been developed in Liaohe Oilfield Petroleum Development Company and its application result is good.