摘要
在传统的分布式操作系统灾备处理过程的基础上,结合已有分布式跨边界片段连接优化方法,提出基于空间片段拓扑连接优化的关系代数转换原则,通过利用等价转换规则,进一步简化经过数据本地化处理后的查询树。然后引入连接归并树和执行计划树等概念,并利用相应归并和优化算法将全局空间查询转化为各个场地局部空间数据库的具体执行计划。
In order to integrate the existing optimizing methods into the conventional query processing method of distributed data -base, this paper presents series transformation rules of relational algebra expression based on cross -border topological join optimi-zation rules.And the processed query tree is further optimized by equivalent transformation after data localization .Finally, we put forward some new concepts including query merged tree and execution plan tree .By using the corresponding merged and optimi-zing algorithm the global spatial query can be transformed into some local fragments joins effectively .
出处
《计算机与现代化》
2013年第12期62-67,共6页
Computer and Modernization
基金
西安市科技创新计划基金资助项目(CX12189WL17)
关键词
查询优化
空间数据查询
空间拓扑连接
等价转换
跨边界片段
query optimization
spatial data query
spatial topological join
equivalent transformation
cross-border fragments
