AW: Re: [Qgis-user] QGIS mapserver performance

[Marco Hugentobler]

Hi Stefan

It could be a problem either with the FastCGI setup or with the layer cache in 
the server. 

If you look at the operating system process list after the QGIS server request 
has finished, do you still see an active entry? If not, it could be that it 
runs as a normal cgi instead of fastcgi.

Regards,
Marco


Am Montag, 21. März 2011, um 08.38:49 schrieb Ziegler Stefan:
> Hi Andi
> 
> > What exactly do you mean by "rendering straight from postgis"? What
> > software is rendering straight from Postgis? UMN Mapserver, or what
> > other renderer? Or your own renderer?
> 
> No, "straight from postgis" means adding the layer in QGIS from postgis.
> I save this qgis project and make it available as WMS. Since there is
> only QGIS (as renderer) involved I thought there would not be a big
> performance difference. Ok, there is apache who is handling the cgi
> request but that won't take 4 seconds.
> 
> > There are some performance bottlenecks regarding clipping of
> > larger/more
> > complex polygons. Marco can tell you more.
> 
> I don't think it's a clipping issue since it's fast when adding the same
> layer 'straight from postgis' :) So there must be some additional work
> when making a detour.
> 
> 
> regards
> Stefan
> 
> > Andreas
> > 
> > On 3/20/11 2:44 PM, Ziegler Stefan wrote:
> > > Hi
> > > 
> > > I have some questions concerning the performance of qgis
> > 
> > mapserver: Using layers with a small amount of polygons I do
> > not see a big difference between rendering the same layer
> > straight from postgis and from local qgis mapserver
> > installation. For a layer with some 400'000 polygons it takes
> > approx. 4 seconds from qgis mapserver (even for large scales
> > with only some polygons to render). But it only takes some
> > fractions of a second when the layer is rendered straight
> > from postgis (and growing with smaller scales ->  more polyons).
> > 
> > > Everything is running on a dual core laptop. So there
> > 
> > should be no big download bottleneck. No special styles are
> > applied to the layers (just a simple fill and an outline).
> > Are there some requests in addition to "GetMap"? Or what's
> > responsible for this big difference?
> > 
> > > regards
> > > Stefan
> > > 
> > > Mit freundlichem Gruss
> > > Stefan Ziegler
> > > Leiter amtliche Vermessung
> > > 
> > > Amt für Geoinformation
> > > Rötistrasse 4
> > > 4501 Solothurn
> > > 032 627 75 96
> > > _______________________________________________
> > > Qgis-user mailing list
> > > Qgis-user at lists.osgeo.org
> > > http://lists.osgeo.org/mailman/listinfo/qgis-user
> > 
> > _______________________________________________
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> > Qgis-user at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/qgis-user


-- 
Dr. Marco Hugentobler
Sourcepole -  Linux & Open Source Solutions
Churerstrasse 22, CH-8808 Pfäffikon SZ, Switzerland
marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
Technical Advisor QGIS Project Steering Committee