计算机与数字工程2012，Vol.40Issue(6)：27-29,3.
查询优化代价估计中的直方图方法运用
Application of Histogram Method on Cost Estimate in Query Optimization
摘要
Abstract
Histogram is a tool most commonly used in database system to estimate the cost of query. It categorizes and sets barrels to all tuples in the relations, calculates the size respectively for each barrel, and then summarizes the data, which makes the price value closer to the reality. Histogram method is the easiest in application and maintenance of all the methods for cost estimation. Each kind of histogram shows different features and varies in accuracy of cost estimation. In application of the actual project, this research works out a method that converts the connection of the relations to a variety of histograms and direct concrete steps to estimate the operation cost by using histograms.关键词
直方图/代价估计/数据连接/优化/元组Key words
histogram/ cost estimation/ data connection/ optimization/ tuple分类
信息技术与安全科学引用本文复制引用
冯凯平,张华,冯超颖,陈衡..查询优化代价估计中的直方图方法运用[J].计算机与数字工程,2012,40(6):27-29,3.基金项目
四川省高等学校重点科研项目《基于项目反应理论的试题三参数评价研究与应用》(编号:11ZA178)资助. （编号:11ZA178）
