Research And Implementation Of Parallel Query Optimization Based On Table Cache Techniques

With the rapid development of Internet, a huge amount of all kinds information resource was produced and stored in database. The volume of database has greatly increased. Multi-database is becoming one of the means to manage massive data. But how to store and manage massive data using Multi-database and provide high performance query process is one focus that attract people's attention. Aggregation query is used most frequently in data process and analysis. How to improve the query performance of aggregation query becoming very useful. At the same time, text retrieval is a kind of time-consuming query, which is also need to enhance query performance.Firstly, studyed the general parallel query process algorithm, decompose the query that dispathed to the local database which reduce the search space greatly and improve the performance of local database. To solve the merge problem of local database result, we introduce multi-way join algorithm, double buffer pool, thread prefetch mechanism to highten the efficiency of local database result merge and impove the whole efficiency of parallel query service.Secondly, Introduced text cache machanism, preserved content retrieval keyword and query result in cache database which improve text retrieval efficiency and reduce the responce time of text retrieval.All these research work is based on MDMP. On the base of our study, we implemented these research works. The practical tests indicate that the performance of this system is better than the target we desired.