On Fri, 24 May 2019 at 18:25, Régis Haubourg <[email protected]> wrote: > > Hi all, > I'm facing very slow opening of project files for a customer here in QGIS > 3.4.5. Something like 7 minutes, against 30 s in QGIS 2.18. > > We are still investigating to narrow it down, but I faced a first query in > the logs that I fail to understand. > > QGIS emits this at a point:
> > And this query is long in our context, 1.7s, because of a very high number of > tables and schemas in that production DB. > > I found at [0] in the postgres provider where it comes from, I found the > associated PR [1], but I fail to understand in what workflow this table is > created using QGIS, and what it is used for. > > Can someone put some light here ? There's a unit test at https://github.com/qgis/QGIS/pull/3439/files#diff-99b101819133a316786604243f3abf6eR318 and https://github.com/qgis/QGIS/pull/3439/files#diff-03e6d7f6f76fb4bcab508984d0fd05f6R443 which partially explains this -- it looks like it's a way to specify a default editor widget configuration for a table, which is used whenever that table is loaded into QGIS. > > select count(*) > > from information_schema.tables > > where table_name = 'qgis_editor_widget_styles' ; > Looks like that query could be substantially improved -- it's only testing for existence of the table, so calculating the count is inefficient and requiring a whole table scan. Nyall _______________________________________________ QGIS-Developer mailing list [email protected] List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
