[Qgis-developer] RE: [Qgis-user] Postgis speed with QGIS

[luca_manganelli at comune.trento.it]

qgis-user-bounces at lists.osgeo.org scritti il 10/06/2010 09.34.14

> Main thing is that the "use estimated metadata" won't make much
> difference if it is mainly fetching data that is slowing things
> down.  Perhaps there is some resource contention on Postgres ..
> generally we are not using the same box for the server and qgis
> (though like you, I expect, I do that from time to time for development
work).

> I'll be interested in anything else you learn that improves performance.

It would be interesting to find a way to reduce the amount of data fetched.
Given a high scale, it is useless to get features so tiny and thus they are
not visible on the map.

I.e. at 1:100.000 QGIS can decide to get line features with ST_LENGTH
longer than 5 meters, or polygons with ST_AREA at least 2,5 m^2.

But I don't know how this strategy would improve performance.