[postgis-users] st_within too slow?

[Pedro Doria Meunier]

Hi All,

I was using the legacy operator && for determining if a point was inside
a particular geometry as thus:

SELECT road_network, toponymy FROM maps AS m WHERE m.b_box &&
geomfromtext('POINT($lon $lat)',4326)

When I was faced with two geometries such as Portugal and Spain country
boundaries I began always getting the row for Spain when I was trying to
get the map of Portugal for a point inside it.

It led me to the conclusion that the && operates as a bounding box for
the corresponding geometry where, in this particular case, the bounding
box of Spain *overlaps* the one of Portugal.

So I was forced to update the query to this:

SELECT road_network, toponymy FROM maps AS m WHERE
st_within(geomfromtext('POINT($lon $lat)',4326), m.b_box)

It works but with a catch: it takes ~200ms where the && took
~25ms ... :-(

Before you ask: yes, I've created the correspondent indices using gist.

Is there any way I can work around this or optimize it?

P.S. I'm using PostgreSQL 8.2.9 on x86_64, PostGIS 1.3.3, geos 2.2.3,
proj 4.5.0

Thank you in advance for any insight on the matter.

Regards,

-- 
Pedro Doria Meunier <pdoria at netmadeira.com>
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