一种新的用于估算查询结果大小的直方图方法

提出了一种新的用于估算查询结果大小的直方图方法。方法的基本思想与人类的思维机制是一致的,即在划分数据时,使所有直方开始于相对前一直方发生较大波动的项,并且结束于相对本直方发生较大波动的项之前。关于新的直方图方法,该文进行了大量的模拟实验。实验结果表明,该直方图方法估算精确,实现效率高,有较好的实用价值。

A New Histogram Method for Size Estimation of Query Result

In this paper,a new histogram method for the size estimation of q uery result is presented.Its basic idea is the same as the thinking mechanisln of human beings.That is to say,a new bucket begins at a heavy change and stop s before the next heavy change.A lot of experiments are carried out as well.T he result of the experiments shows the new algorithm has higher estimation accu racy,and can be implemented more effectively and efficiently.So it has good ap plication value.