Re: An unresolved performance problem. - Mailing list pgsql-performance

On Thu, May 08, 2003 at 10:48:52AM -0200, Achilleus Mantzios wrote:

> That is, we have a marginal decrease of the total cost
> for the index scan when random_page_cost = 1.9,
> whereas the "real cost" in the means of total runtime
> ranges from 218 msecs (seq scan) to 19 msecs (index scan).
> (is it sane?)

You're right that the problem is the poor estimate of the cost of
that selection.  I recall you mentioning that you'd expanded the
statistics on the field, but I don't recall to what.  I know that
under some circumstances, you _really_ have to increase the stats to
get a meaningful sample.

A

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