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

[Adam Nielsen]

> Thanks for your suggestions. I added the layer to the slow project
> and it's still slow. The project, and the layers in it, are generally
> responsive and there's no especially complex styling. The issue is
> only when editing, specifically editing nodes, with topological
> editing enabled, on PostGIS layers (not memory layers or shapefiles).

Did you re-add the PostGIS connection too, or reuse the existing one?
I'm just wondering whether there could be something different in the
connection settings that leads to one being slower than the other.

In the fast project, once you have edited the features, did you then
try to save the changes?  I am just wondering whether the slow project
is configured to commit changes to the DB after every modification,
whereas the fast project might default to not writing anything to the
DB until you save the layer.  If so, the fast project may still be
sluggish when you go to save your changes back to the DB.

> The PostGIS server is running on an AWS EC2 instance via an ssh
> tunnel. I'm traveling and I went from a fairly fast internet to a
> slower one and the slow project went from slow to very slow. So I
> guess that's a clue.

If you're on a Linux-like platform, you could try using zcat or gunzip
to decompress the project file into an XML file, and then examine it in
a text editor or web browser.  You could find the section where the
PostGIS connection details are stored, and compare them between the
fast and slow project, to see if there is any difference?

Likewise you could find the section where the layer is described and see
if there are different options applied to it.

> It's not a big deal, obviously I can recreate the project. I was
> mainly curious since I have not run into this in other projects and I
> thought that maybe I was overlooking something.

I would think comparing the two decompressed project files might be the
most likely way to figure out what differences exist that might be
causing this.

To simplify things you might want to compare that slimmed down version
of the slow project, where you removed all the layers except for the
slow one.

Cheers,
Adam.