基于扩展分区的分布与并行数据库级联扩展技术

首先介绍扩展分区的概念；然后介绍分布式服务器和并行服务器级联模式下的C／S 通讯管理，查询分解和事务管理等关键问题，最后进行性能测试，比较了在纯分布式（非多级模式）和分布与并行级联模式（多级模式）下的查询性能。

Research on DM Databases' Multi-tier Server Architecture

Nowadays, database applications' scale become more and more larger, the number of users have been increasing rapidly, especially in mobile computing environment, the potential users who will access to database server are much more greater than those in traditional network computing environment. Higher system performance requirements are exposed on the system. In order to guarantee the system performance, multi-tier C/S database architecture is proposed. Till now, we have developed a parallel DBMS prototype PARO and a distributed DBMS DM3. In this background, we have carried on the research of the integration of the distributed database and parallel database technology. In this paper, we first introduced the conception of extensive partition. Then we discussed the some key issues including C/S communication management, query decomposition and transaction management. At last, the test results are given. From the test results, it is can be shown that the DM database in multi-tier database server mode performs better than that of pure distributed database mode. Besides these, DM multi-tier architecture has more widely application scope due to combine the distributed database's autonomy with the parallel database's high performance.