Semi-Closed Cube： An Effective Approach to Trading Off Data Cube Size and Query Response Time  

作　　者：Sheng-EnLi ShanWang 

机构地区：[1]DepartmentofComputerScienceandTechnology,ShandongInstituteofArchitectureandEngineeringJinan250014,P.R.China／／SchoolofInformation,RenminUniversity,Beijing100872,P.R.China [2]SchoolofInformation,RenminUniversity,Beijing100872,P.R.China

出　　处：《Journal of Computer Science & Technology》2005年第3期367-372,共6页计算机科学技术学报（英文版）

基　　金：国家自然科学基金，国家高技术研究发展计划(863计划)，国家重点基础研究发展计划(973计划)

摘　　要：The results of data cube will occupy huge amount of disk space when the base table is of a large number of attributes. A new type of data cube, compact data cube like condensed cube and quotient cube, was proposed to solve the problem. It compresses data cube dramatically. However, its query cost is so high that it cannot be used in most applications. This paper introduces the semi-closed cube to reduce the size of data cube and achieve almost the same query response time as the data cube does. Semi-closed cube is a generalization of condensed cube and quotient cube and is constructed from a quotient cube. When the query cost of quotient cube is higher than a given threshold, semi-closed cube selects some views and picks a fellow for each of them. All the tuples of those views are materialized except those closed by their fellows. To find a tuple of those views, users only need to scan the view and its fellow. Thus, their query performance is improved. Experiments were conducted using a real-world data set. The results show that semi-closed cube is an effective approach of data cube.The results of data cube will occupy huge amount of disk space when the base table is of a large number of attributes. A new type of data cube, compact data cube like condensed cube and quotient cube, was proposed to solve the problem. It compresses data cube dramatically. However, its query cost is so high that it cannot be used in most applications. This paper introduces the semi-closed cube to reduce the size of data cube and achieve almost the same query response time as the data cube does. Semi-closed cube is a generalization of condensed cube and quotient cube and is constructed from a quotient cube. When the query cost of quotient cube is higher than a given threshold, semi-closed cube selects some views and picks a fellow for each of them. All the tuples of those views are materialized except those closed by their fellows. To find a tuple of those views, users only need to scan the view and its fellow. Thus, their query performance is improved. Experiments were conducted using a real-world data set. The results show that semi-closed cube is an effective approach of data cube.

关 键 词：warehousing OLAP (on-line analytical processing) data cube 

分 类 号：TP311.13[自动化与计算机技术—计算机软件与理论]