Oracle Spatial 的空间查询 处理机制分析及优化
学 专 年 姓
院 业 级 名
计算机科学与技术 计算机科学与技术 2006 级 张连帅 张坤龙 6月 21 日
指导教师 2010 年
摘
要
随着信息技术的发展, 空间数据的应用日益广泛, 也越来越受到人们的重视. 但是,由于空间数据自身的特点,查询空间数据要花费大量的时间,所以空间查 询的效率问题一直是人们关注的重点. 众所周知,Oracle Spatial 是存储,管理,查询空间数据最好的工具之一,因 此本文针对 Oracle Spatial,设计并实现了一个空间查询优化中间件,提高了空间 查询的效率.在实现的过程中,首先分析空间查询的执行计划,并与普通一维查 询的执行计划进行对比,通过对比可知 Oracle 仍采用通常的一维查询优化机制 来处理空间查询,因此需要一个空间查询优化中间件来提高查询效率;然后依据 将空间查询与非空间查询分开执行的原理,对 SQL 语句进行分解,重组,将生 成的优化后的 SQL 语句提交给 Oracle 执行;最后,经过与原 SQL 语句的查询耗 时对比后发现,优化后的 SQL 语句确实减少了执行时间.因此,可得出查询优 化中间件确实提高了空间查询的效率的结论. 关键词:Oracle Spatial;OCI;空间数据;空间查询;优化
ABSTRACT
With the development of IT,spatial data is used more and more widely,and more and more attention has been paid.But because of the feature of spatial data,the spatial query costs lots of time,so people have always focused on the efficiency of the spatial query. As we know,Oracle Spatial is one fo the best tools that is used to store,manage and query spatial data,so this article which based on Oracle Spaital ,designed and realized a plug-in that optimizes the spatial query,and improved the efficiency of the spatial query.Firstly,we analysed the explain plan of the spatial query and compared with the explain plan of the ordinary query,we achieved the conclusion that Oracle still use the ordinary optimize method to deal with the spatial query,so we need a plug-in that optimizes the spatial query to imporve the efficiency of the spatial query.Then based on the theory of separating the spatial query from the ordinary query,through dissecting and recombining the SQL statement,we submitted the SQL statement that has been optimized to Oracle.Finally ,we compared the time that optimized spatial query cost with the time that unoptimized spatial query cost and found that the time did cost less.So we can assure that the plug-in do improve the the efficiency of the spatial query. key words: Oracle Spatial;OCI;Spatial data;Spatial query;Optimize
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