AnyQuery:网格环境下基于服务的分布式查询处理系统

AnyQuery是一种适用于网格环境、基于服务的分布式查询处理系统，使用统一的数据格式（可扩展标记语言）来表示和传输数据，所有组成模块以网格服务的形式实现，网格服务之间通过标准的接口进行通信．这种接口和实现分离技术屏蔽了不同数据库及其运行节点的差异，为用户提供一致的虚拟关系数据视图和分布式数据查询支持．在分析和研究已有的并行数据库和分布式数据库查询技术的基础上，AnyQuery提出和实现了一种适用于动态网格环境的分布式查询计划生成和执行算法，该算法能够根据网格环境中各节点及其连接网络的实际情况确定查询计划，支持跨数据库的连接查询．基于Globus 3．0开发了AnyQuery的原型系统，性能测试表明该系统具有较好的可扩展性，尤其适合计算密集型的复杂查询．

AnyQuery: a Service-based Distributed Query Processing System in the Grid

This paper proposed AnyQuery, a service-based distributed query processing system to solve the problem of accessing and integrating multiple relational databases in the grid. All the modules of the system are implemented as grid services, which communicate with each other through standard interfaces. XML is used as the data representing and exchanging format. The interfaces and implementations are totally separated in this system. AnyQuery provides a uniform virtual data view above multiple relational databases in the grid. Grid users can issue their queries based on the virtual view. A distributed query processing algorithm is presented to deal with dynamically changed grid environment, which can make the query plan according to the varied grid computing and communicating capacities and support join query across multiple relational databases. A prototype is developed and the performance evaluation demonstrates its effectiveness, especially for complicated computing-intensive query.