Bug report #18406
QGIS 3 is about 3 times slower when calculating attributes.
|Affected QGIS version:||3.1(master)||Regression?:||Yes|
|Operating System:||Easy fix?:||No|
|Pull Request or Patch supplied:||No||Resolution:||not reproducable|
|Crashes QGIS or corrupts data:||No||Copied to github as #:||26296|
When calculating attributes, QGIS 3.0 and 3.1 are about 3 times slower than 2.18
Tested on a simple GeoPackage and non-geometry Shapefile by updating 1k, 5k and 10k features with a constant number (just updating, without saving changes).
In all tests 2.18 needed about 1 sec for 1000 rows, while QGIS 3.0 & 3.1 about 3 sec. GDAL 2.2.3 in both cases.
I was also told by a Windows user that he aborted updating 120k features (Shapefile) after 5 hours.
#5 Updated by Borys Jurgiel over 2 years ago
Alessandro, when started writing a simple script, I realized adding simple (geometryless and attributeless) features is yet slower... Or something is wrong with my build.
On my laptop:
QGIS 2.18 (from Buster) ~0.6s
QGIS 3.1 (compiled) ~2.1s usually; occasionally ~1.3s
import timeit l = QgsVectorLayer("Point?crs=epsg:4326&field=x:integer", 'test', 'memory') pr = l.dataProvider() def addFeature(): pr.addFeatures([QgsFeature()]) timeit.timeit(addFeature, number=100000)
Could anyone confirm please (in the Python console)?
#7 Updated by Borys Jurgiel over 2 years ago
- Resolution set to not reproducable
- Status changed from Open to Closed
Nyall - thanks, the build type was set to None and after setting to Release, it's a bit faster. QGIS 3 is still significantly slower than 2.18 when adding features from Python (over 2x for empty features and ~1,5x for features with a geometry and one attribute), however, it was a side problem and adding 100k features in 2-3 seconds isn't any tragedy I guess.
I can't reproduce the original problem (slow updating attributes by the Field Calculator). What was taking 10s in QGIS 2.18 and 30s in QGIS 3 now works immediately. I'm closing it until I have any new observations.