[postgis-users] GIST index speed
schabi at logix-tt.com
Thu Jun 5 02:34:38 PDT 2008
"Paul Ramsey" <pramsey at cleverelephant.ca> wrote:
> First, basic index concepts: when you are requesting the whole data
> set, the index (any index) does *nothing* for your performance. To
> use an (obsolete) metaphor, if you are checking out *every* book in
> the library, do you first go to the card catalog?
> So your test case isn't testing anything index related.
Acutally, when most geometries do not even touch the bounding box of
his given query geometry, an index could speed up the whole query.
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf. | Software Development GIS
Fight against software patents in Europe! www.ffii.org
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