[postgis-users] performace question

[Paul Ramsey]

You have spatial indexes on the tables I assume?



On 1-Apr-09, at 7:26 AM, Martin Landa <landa.martin at gmail.com> wrote:

> Hi,
>
> I am beginning with PostGIS and I wonder about performance, e.g.
> having layer 'regions' = 'obce' (polygon) and boundary of CZ = 'cr'
> (polygon).
>
> SELECT count(obce.gid) FROM obce;
> count
> -------
>  6361
> (1 row)
>
> SELECT count(obce.gid) FROM obce,cr WHERE ST_Touches(obce.the_geom,
> cr.the_geom);
> count
> -------
>   285
> (1 row)
>
> Time: 258271.730 ms
>
> It seems to be quite long time, any hits about configuration of
> PostgreSQL, query optimalization?
>
> PostgreSQL 8.1.15,  1.4 USE_GEOS=1 USE_PROJ=1 USE_STATS=1
>
> Thanks in advance, Martin
>
> -- 
> Martin Landa <landa.martin gmail.com> * http://gama.fsv.cvut.cz/~landa
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