On Sun, 10 Apr 2011, Jesper Krogh wrote:
On 2011-04-10 12:18, Oleg Bartunov wrote:
Wow, custom solution for 2008 still much faster Denali 2011 solution.
Also, what's about not spatial data types ? In our approach, we can provide
knn for any datatype, which has GiST index and distance method.
Can you share some insight about how it would
work if the distance method is "expensive" (as in 100ms)?
I don't understand how does your question connected with my statement :)
Slow distance calculation affects gist-based ordered heap output as well as
seqscan output from heap, but in the first case you need to calculate just a
few distances (something like height of gist tree), while in the naive way
one have to calculate n^2 distances.
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: o...@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83
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