Degree of clustering

Hi, What is degree of clustering. If I say the degree of clustering is 60. Will it mean that 60% of the data is in the same order as of the indexes or 40% of the data is in the order of the indexes. Rajesh

It is an estimate of the percentage of the table that is still in order. It is used by the optimizer to decide if there is still any value to relying on the ordering of the data for speed and reduced I/O. Normally when performing indexed reads the optimizer has to assume that there will be one page read for each row accessed, however if the table is clustered it can assume that there will be (2020/rowsize) rows access per page read and it can reduce the estimated cost accordingly. The estimate is used to determine whether this is still a valid assumption. Art S. Kagel Savio Mario Bartholomeo Pereira wrote: > > Hi, > What is degree of clustering. > If I say the degree of clustering is 60. Will it mean that 60% of the data > is in the same order as of the indexes or > 40% of the data is in the order of the indexes. > > Rajesh