一种高效的实视图选择算法  

An Efficient Material View Selection Algorithm

作　　者：张举 耿海军 ZHANG Ju;GENG Haijun(School of Software Engineering,Shanxi University,Taiyuan 030006,China;State Key Laboratory of Networking&Switching Technology,Beijing 100876,China)

机构地区：[1]山西大学软件学院,太原030006 [2]网络与交换技术国家重点实验室,北京100876

出　　处：《太原师范学院学报（自然科学版）》2019年第3期56-61,77,共7页Journal of Taiyuan Normal University:Natural Science Edition

摘　　要：数据往往被存储在分布式的数据源中,当需要对数据做查询操作时,就无法像查询单数据源那样有效率.联机分析处理(OLAP)被提出,并用来克服这个问题.在这个过程中,为了提高OLAP的查询效率,采用了将视图实体化的技术,即将综合性的复杂的查询结果放入实视图中,再将OLAP查询与实视图相互关联起来.但是,实视图需要占据大量的物理存储空间,而当数据源一旦更新时,为了与底层数据源保持一致,必须对实视图进行相应的更新维护,从而产生实视图的维护代价,因此实视图选择必须在提高查询响应速度和资源限制二者之间做出一定的权衡.文章提出了一种算法,可以在对维护代价一定条件约束下,使得查询代价达到最小的算法.经过实验,该算法不仅计算复杂度较小,而且维护成本较低.Data warehouse is an in-advance approach to the integration of data from multiple,possibly very large,distributed,heterogeneous databases and other information sources in order to support management decisions.Most of the query is concerning about integrated information,which needs to access different data sources to get results.It is time-consuming.Therefore,the technology of materialized view is used to accelerate query speed,which stores the pre-computed views in the data warehouse,so it can get the query results directly from materialized views when running OLAP queries.Therefore it can avoid the complexity and comprehensive query on the underlying tables.However,materialized views need to occupy some storage space,and materialized views must be maintained when the data source is updated.So it needs to get the trade-off between the response time and resource constraints.An algorithm was proposed to select a set of materialized views under maintenance cost constraints for the purpose of minimizing the total query processing cost.The algorithm adopts the dynamic penalty function to solve the resource constraints view selection.Experimental results show that the algorithm not only has less computational overhead,but also has lower maintenance cost.

关 键 词：数据仓库 实视图选择 遗传算法 

分 类 号：TP311.13[自动化与计算机技术—计算机软件与理论]