QGIS » QGIS Application

It is hard to believe that it takes several seconds to update a WMS map if server is working OK. Could you try with an empty project in EPSG:4326 by adding for example "Countries" layer from http://www2.demis.nl/WMS/wms.ashx?wms=WorldMap? Does it still take seconds before the map is updated on the map?

I can also confirm the same thing for your WMS server. Using the same machines:

*QGIS 2.2: < 1 second (Very responsive and I also like the little count-up indicator in the bottom left of the screen, which is missing in the current build)
*QGIS 2.3 (todays build): Sometimes up to 5 seconds! General sluggish behaviour. Sometimes screen turns dark for a few seconds (indicator that Ubuntu is waiting for the application to respond). Sometimes decides to not render at all until I restart the application.

If the issue really has something to do with multithreading, could it be that your good ol' T43 is not the best device for testing?

I tested this again and it is still slow in the master version. This is a good server to notice the lag:

http://gisgba.geologie.ac.at/ArcGIS/services/karten_image/is_md_gk50/ImageServer/WMSServer?request=GetCapabilities&service=WMS

Tobias Sch wrote:

I tested this again and it is still slow in the master version. This is a good server to notice the lag:

http://gisgba.geologie.ac.at/ArcGIS/services/karten_image/is_md_gk50/ImageServer/WMSServer?request=GetCapabilities&service=WMS

in

settings -> options -> rendering

did you activated the parallel rendering choosing how many cores you want to use?

I did it, and there isn't much difference with qgis 2.2

I tried around with those option. But I think it is more the communication with the WMS-server which is producing the lag.

Tobias Sch wrote:

I tried around with those option. But I think it is more the communication with the WMS-server which is producing the lag.

I just made another test, two computers (both i7 4 cores) side by side, both Linux (same flavor/version), same connection, one with QGIS 2.2 and the other master. Then I added and zoomed (by single clicks) the map in the above service, and there wasn't any kind of appreciable difference.

Tobias Sch wrote:

@Giovanni - How many seconds does it take to render the map? I have around 2 seconds on QGIS 2.2 and 4 to 5 seconds on master.

I don't know if it is 2, but definitely not 4/5.

Anyway as soon as another pair of hands will show around here I will make a video and show it to you.

If you want you could use my qgis2img tool (https://github.com/DMS-Aus/qgis2img) to get some render stats.

Tobias Sch wrote:

@Giovanni - How many seconds does it take to render the map? I have around 2 seconds on QGIS 2.2 and 4 to 5 seconds on master. I attached some screenshots which show at least for the processor much broader times to draw the map. The peaks of network activity almost seem like QGIS master is fetching the map multiple times from the WMS server.

this is what I get with the "time" command when opening a QGIS project with the layer (zoomed at 1:75000) published in the above WMS server.

Master:

user 0m3.220s

user 0m3.404s

user 0m3.232s

user 0m3.144s

QGIS 2.2:

user 0m3.652s

user 0m3.432s

user 0m3.652s

user 0m3.564s

I updated the Lenovo (Lenovo SL 510, Intel Core 2 Duo, GM45 graphics) to QGIS 2.4

WMS performance has stayed just as fast as with 2.2. Is the problem maybe the combination of Hyperthreading and Ubuntu? Is there a way to analyse the network traffic of QGIS?

WMS performance has stayed just as fast as with 2.2. Is the problem maybe the combination of Hyperthreading and Ubuntu? Is there a way to analyse the network traffic of QGIS?

I use Ubuntu (and Windows, for QGIS testing) and as you already know I cannot observe this issue.

Did you see this on other machines (with the same OS, or not)?