On Fri, 2007-04-20 at 12:07 -0700, Andrew Lazarus wrote: > I have a table with 2.5 million real[] arrays. (They are points in a > time series.) Given a new array X, I'd like to find, say, the 25 > closest to X in some sense--for simplification, let's just say in the > usual vector norm. Speed is critical here, and everything I have tried > has been too slow. > > I imported the cube contrib package, and I tried creating an index on > a cube of the last 6 elements, which are the most important. Then I Have you tried just making normal indexes on each of the last 6 elements and see if postgresql will use a BitmapAnd to combine them? Regards, Jeff Davis