On Mon, 05 Dec 2005 10:11:41 -0500, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: >> Correlation -0.0736492 >> Correlation -0.237136 >That has considerable impact on the >estimated cost of an indexscan The cost estimator uses correlationsquared. So all correlations between -0.3 and +0.3 can be considered equal under the assumption that estimation errors of up to 10% are acceptable. Servus Manfred
