On Fri, Mar 10, 2006 at 09:14:27AM +0000, Clive Page wrote: > I have a table cov3 of about 3 million rows, with a B-tree index on an > integer column called hpix. If I do a simple select on this column it > works in milliseconds, using the index naturally: <snip> > So I would like to use this function to find rows, and I try for example: > > select * from cov3 where hpix = healpix(2.85,-11.48); > > but it takes ages. An EXPLAIN shows why, it insists upon a sequential > scan: <snip> You don't describe the exact structure of your table nor the exact declaraion of your function, but is it possible your function is marked VOLATILE rather tha STABLE or IMMUTABLE? > I am using Postgres 8.1.0 on Linux. Hope this helps, -- Martijn van Oosterhout <kleptog@xxxxxxxxx> http://svana.org/kleptog/ > Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a > tool for doing 5% of the work and then sitting around waiting for someone > else to do the other 95% so you can sue them.
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