[postgis-users] performance of intersects(a,b)

[Willy-Bas Loos]

Hi,

I´ve noticed that intersect(a,b) is slow when i compare a (nice and large)
geometry with itself.
so the syntax is:

select 'yes' as foo
from table1 a, table1 b
where a.gid=4
and b.gid=4
and intersects(a.the_geom, b.the_geom)

This particular polygon has about 10 000 points, and the query runs for 4
whole seconds.
At the first point that is being compared, however, PostGIS should notice
that it has a "positive".

I´m only using postgis 1.0, so this migt have been changed allready. Has it?

WBL
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