Bug report #11186
Deleting records from a table is very slow when the table is open for viewing
|Affected QGIS version:||2.18.17||Regression?:||No|
|Operating System:||Easy fix?:||No|
|Pull Request or Patch supplied:||No||Resolution:||end of life|
|Crashes QGIS or corrupts data:||No||Copied to github as #:||19498|
Tens of minutes for a PostGIS table with 200k records, with qgis taking 100% of CPU. The issue was apparently fixed some time ago by Kuhn by introducing some kind of "batch job detection" on attribute table side.
#1 Updated by Matthias Kuhn over 5 years ago
The problem most likely is introduced by the fact, that each feature is deleted with a separate call to
QgsVectorLayer::deleteFeature( QgsFeatureId fid ) which in turn leads to one signal being emitted for each deleted feature and the attribute table updates accordingly with a expensive operation.
The same applies to adding features/changing attributes.
IIRC I resolved it for changing attributes by watching for editCommandStarted()/editCommandEnded() signals on attribute table side and buffering any edit happening in between, but only updating the attribute table once in the end (batch job detection).
The same could be done for deleting features on attribute table side. Instead I would propose to implement this feature directly inside QgsVectorLayer and emit batched signals for operation happening inside an edit command and per-operation signals when outside an edit command. This would have the advantage of not having to reinvent the wheel for every part where expensive operations can be performed once per edit command.
#5 Updated by Giovanni Manghi about 1 year ago
- Resolution set to end of life
- Status changed from Open to Closed
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