Informix uses height-balanced histograms ( that is, equi-height / equi-depth ) with overflow buckets as opposed to the width-balanced histograms ( equi-width ). Informix使用带溢出桶(overflowbucket)的高度平衡直方图(即等高/等深),而不是宽度平衡直方图(等宽)。
How can you tell if you are going to overflow your bucket if you dont know how full it is? 如何让你在不知道水桶有多满的情况去装水,你怎么能判断水会不会溢出来?