[Qgis-user] QGIS really slow with .gpkg layers

[Nicolas Cadieux]

Hi,
I also used txt files to load LiDAR points in QGIS because .shp was not good.  This was before .gpkg came along, before I learned Python or CloudCompare.   I am just starting to familiarize myself with the geopackage format so i am no .gpkg expert but this is what I would do or ask myself:

How are the files stored? Server, USB stick, hard-drive, SSD? 

Are the files in the same CRS as the project?  If not, every thing may be read in cache and reprojected even before you start...

What happens when the files are simplified?  Try more files and less layer, try more points in the same files. Try a fresh project an open the layers one by one.  Is one more problematic than others?  Enough memory? Disable all plugins.

Caching features: in your QGIS options, you can change the amount of featured that are cashed when you open a lector layer.  Try cashing more feature or much less features (like 1).  What happens?  If you have a max of 16000 features per layer, chances are you are caching everything so everything is being loaded to memory.

File creation: how are the files created?  Look at the options in Gdal if the files are created in QGIS.  https://gdal.orgdrivers/vector/gpkg.html Try creating the files with Gdal translate (vector menu) instead of just “export as” or save as in QGIS, force extra option to force index creation.

Do you have a spatial index build in? In theory .gpkg comes with a spatial index but perhaps you can rebuild one? Or make sure you build on from the start when you create the file. (See above).

I remember that when I created a .gpkg in python, and used it in ArcGis, the file would take a long time to open because it was reading every point of the file in order just  to get the files extent. Maybe that is going on?  I think you can specify the files extent in the file metadata.  (I would need to check my code but I don’t see my solution here. I normally post them whenI find them...). https://gis.stackexchange.com/questions/374408/using-geopandas-generated-gpkg-in-arcmap 

Just a bunch of ideas...

Nicolas Cadieux
https://gitlab.com/njacadieux

> Le 10 déc. 2020 à 09:41, Francesco Pelullo <f.pelullo at gmail.com> a écrit :
> 
> 
> Hi all,
> 
> I'm running QGIS 3.10 LTR on Windows 10.
> 
> My project has 6 .gpkg files connected, everyone of these has 14 layers with points geometries, every layer counts about 16.000 features.
> 
> So my QGIS project manage about 1.344.000 points, not used at same time.
> 
> When i open this project, QGIS needs about 15 minutes for go ready.
> 
> Instead, if i store these points in separate .TXT files, QGIS needs only few seconds for load layers and go ready. Also .shp layer format seems more performant than .gpkg
> 
> It seems to me that they are not really efficient for these points layers.
> 
> Is this a my problem? Or there are some tricks i could use? 
> 
> .gpkg are vacuumed regularly.
> 
> Best regards 
> 
> Francesco
> 
> 
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