[postgis-users] looking for some perf data
mbdavis at refractions.net
Tue Nov 21 09:12:31 PST 2006
First of all, you need to be more specific. The performance of an index
is related to the kinds of queries you are making on it. If you are
making a simple equality query, then a B-tree on the (x,y) pair is
probably fine. But if you're wanting to do range searches in two
dimensions, a B-tree does not support this kind of query, and hence
performance will be slow compared to an access method which does support
this (e.g. R-tree, quad-tree, etc etc).
I don't know of any reference which has a "hard verifiable" comparison
with a simple B-tree for range queries. I suspect this is because the
performance difference is so obviously bad for B-trees that researchers
haven't bothered to document it.
You might try looking at two of the books by Hanan Samet:
Foundations of Multidimensional and Metric Data Structures
The Design and Analysis of Spatial Data Structures
You could also try the original R-tree papers, or a survey entitled
"R-Trees are everywhere". Also a paper entitled "Multidimensional
Access Methods" by Gaede et al.
raphael Jacquot wrote:
> hi there
> I'm looking for some hard verifiable proof that using r-tree based
> geometry indexes is better than using 2 columns and a btree index on
> it, performance wise.
> has there any study done on that ?
> postgis-users mailing list
> postgis-users at postgis.refractions.net
Senior Technical Architect
Refractions Research, Inc.
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