QGIS with postgis connection hangs when network changes

sickel commented 6 months ago

What is the bug or the crash?

I have a qgis project saved in postgis and using a number of postgis layers at a postgis server at work. I am using this on my work laptop that is partially directly connected to the network at work and partially connected via a VPN. If QGIS is running when the nework is changing, it hangs completely and will not start working again even if the network is back up, when this happen I have to kill the QGIS application.

If I am connected on VPN and turns the VPN off, QGIS will hang, but when I reconnect VPN it starts working again, so I guess the issue is connected to changes in the IP and/or routing between the PC and the server which probably invalides the connection at the server.

I have no idea what QGIS is doing when the UI is frozen, but I would guess it tries to connect to postgis and never gets an answer.

maybe it could be possible to

set a relatively long time out on postgis connections (30 secs?)
if it times out, give the user a dialog telling it has timed out with three choices: 1 Keep on waiting (i.e a long query is running, maybe having a selection to come back after the same time out or keep on running if a long query is going on), 2 Abort (i.e go back, stop what was going on in communication with postgis) or 3 Reconnect (i.e. establish a new connection to the server, retry what was going on)

Another good thing with this is that it would be possible to kill a connection to postgis when running a sql query that is taking too long time.

Steps to reproduce the issue

1 Set up a project with postgis connection to an networked server, save it to postgis 2 Change the network connection to the server to go via a VPN (or the other way around, start connection via VPN, change to direct) - it may be that the same thing happens if e.g. moving between wifi and cable network 3 Error: QGIS hangs solid

Versions

QGIS version | 3.36.1-Maidenhead | QGIS code revision | 3e589453 -- | -- | -- | -- Qt version | 5.15.3 Python version | 3.9.18 GDAL/OGR version | 3.8.4 PROJ version | 9.3.1 EPSG Registry database version | v10.098 (2023-11-24) GEOS version | 3.12.1-CAPI-1.18.1 SQLite version | 3.41.1 PDAL version | 2.6.0 PostgreSQL client version | 16.2 SpatiaLite version | 5.1.0 QWT version | 6.1.6 QScintilla2 version | 2.13.4 OS version | Windows 10 Version 2009 | | | Active Python plugins DataLoader | 1.12 easyPlugin | 1.0.0 felt | 2.0.1 FilterLayersAtOnce-master | 1.0 kartverket_adresse | 1.1 latlonbuffer | 0.1 multi_filter | 0.9 openlayers_plugin | 2.0.0 pg_raster_import | 3.2.0 pluginbuilder3 | 3.2.1 plugin_reloader | 0.9.4 PostGISQueries | 0.2 postgis_geoprocessing | 0.9 postgis_toolbox | 1.1 Qgis2threejs | 2.7.3 QGIS3-getWKT | 1.6 qgisSpectre | 1.21 rrrReader | 0.5 SOSIexpressions | 1.11 stripchart | 1.0 db_manager | 0.1.20 QGIS version 3.36.1-Maidenhead QGIS code revision [3e589453](https://github.com/qgis/QGIS/commit/3e589453) Qt version 5.15.3 Python version 3.9.18 GDAL/OGR version 3.8.4 PROJ version 9.3.1 EPSG Registry database version v10.098 (2023-11-24) GEOS version 3.12.1-CAPI-1.18.1 SQLite version 3.41.1 PDAL version 2.6.0 PostgreSQL client version 16.2 SpatiaLite version 5.1.0 QWT version 6.1.6 QScintilla2 version 2.13.4 OS version Windows 10 Version 2009 Active Python plugins DataLoader 1.12 easyPlugin 1.0.0 felt 2.0.1 FilterLayersAtOnce-master 1.0 kartverket_adresse 1.1 latlonbuffer 0.1 multi_filter 0.9 openlayers_plugin 2.0.0 pg_raster_import 3.2.0 pluginbuilder3 3.2.1 plugin_reloader 0.9.4 PostGISQueries 0.2 postgis_geoprocessing 0.9 postgis_toolbox 1.1 Qgis2threejs 2.7.3 QGIS3-getWKT 1.6 qgisSpectre 1.21 rrrReader 0.5 SOSIexpressions 1.11 stripchart 1.0 db_manager 0.1.20 ### Supported QGIS version - [X] I'm running a supported QGIS version according to [the roadmap](https://www.qgis.org/en/site/getinvolved/development/roadmap.html#release-schedule). ### New profile - [ ] I tried with a new [QGIS profile](https://docs.qgis.org/latest/en/docs/user_manual/introduction/qgis_configuration.html#working-with-user-profiles) ### Additional context _No response_

uclaros commented 6 months ago

I remember postgres connections timing out and qgis unfreezing after some 30 seconds but oracle ones freezing indefinitely - see #35855

Have you tried waiting a few minutes?

sickel commented 6 months ago

I did some more systematic testing jumping back and forth between the wired network and the VPN and it seems to work fine. Please close this issue. I have had some occasions of the project hanging and not coming back after a few minutes, but there are some other things playing in. Sorry for this

qgis / QGIS