[postgis-users] Re: looking for some perf data
sdc at sdc.com.au
Tue Nov 21 15:39:40 PST 2006
Many years ago, I tried to implement a fairly simple GIS application
using separate B-trees on lat/long coordinates.
The idea died as soon as the data volumes became non-trivial.
The reason was obvious in hindsight: a query for x>=g1 and x <=g2 and
y>=t1 and y<=t2 using separate B-trees has to retrieve a "vertical" and
then a "horizontal" slice of the whole world and then take the
R-trees, quad-trees etc greatly reduce this cost.
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