The Research On Query Optimization Strategy For Grid Database

With the development of the grid and the people's request to data application, data grid appears after compute grid. Database plays an important role in data grid. The existing distributed system either have the uniform view or are based on the common structure which takes them huge challenge in the further development. It is an important problem to access and make use of the existing databases in the dynamic grid environment.The query function is used very frequently in the database application. In the grid environment, every database only includes a part of the information and there is high heterogeneity of the node and various communication rates between nodes. So the query is finished in virtual database which is dynamically made among compute nodes. The query process is based on grid service which is dynamically built. It hides the diversities of the bottoms and adapts well to the complex environment of grid.Query Processor is the module which has the most impacts on the performance of databases, so query optimization is quite important. After doing some research on query optimization of the traditional databases, we put forward a query optimization arithmetic which considers communication cost and dynamic environment. The operations are well paralleled according to analyses the node selection strategy. It can select good nodes to deal with operations along with the dynamic grid environment. This arithmetic selects the nodes which have good communication rate to communicate middle result and the nodes which have high compute rate. Experiment shows that this strategy is fit for the principle of the grid database and it can improve the efficiency of the database.