[Qgis-user] what setting effect topological editing performance?

[Adam Nielsen]

> I have an old project that is painful to edit with topological editing
> activated. I put a couple of the layers into a new project and topological
> editing is very quick. Specifically, in the old project, moving a single
> node on a polygon with the vertex tool that does not require any additional
> vertices to be moved takes about 2 minutes to complete but is nearly
> instantaneous in the new project.

What happens if you add the layer again to your existing project,
following the exact same procedure as when you added it to the new
project? (i.e. adding the PostGIS connection again from scratch).

If that's fast then it would point to either an issue with the
PostGIS connection or something to do with layer style.

You could also try using the layer right-click menu to copy the styles
from the old slow project to the new fast one to see if that also slows
down the new project.  I wouldn't have thought it would be the styles
causing the slowdown because although a re-rendering happens when
editing the features, it also happens when dragging the map which you
haven't said is slow, but it can't hurt to rule it out.

Is it only slow when editing the features, or is it also slow when you
first open the project and it's loading the list of features from the
DB?  That could also hint at an issue with the DB connection.

These are only guesses, but perhaps they might help narrow down the
cause of the slowness.

Cheers,
Adam.