[QGIS-Developer] Project loader profiler Postgres Layers

[Nyall Dawson]

On Thu, 17 Nov 2022 at 07:57, Rémi Desgrange via QGIS-Developer
<qgis-developer at lists.osgeo.org> wrote:
>
> @Julien sorry for not being clear, I used the Debugging/Developement tool 😊

Just to clarify -- there's two useful tools in the
Debugging/development tools here:

1. The "Project Load" profiler, which gives an atomic list of actions
taken during project load and how long each took. That's been around
for a number of years now.

2. The new (in 3.26) "Query logger", which lists all database queries
performed by QGIS (and how long they took).

Given that the slow loading of the postgres layers was found through
the first tool, the second tool (the query logger) is the best one to
determine exactly which queries QGIS is making against the database
are the cause of the slow postgres loading times.

Nyall


>
>
>
> @René-Luc Thanks I’ll look into it.
>
>
>
> From: QGIS-Developer <qgis-developer-bounces at lists.osgeo.org> on behalf of René-Luc Dhont via QGIS-Developer <qgis-developer at lists.osgeo.org>
> Date: Wednesday, 16 November 2022 at 10:06
> To: qgis-developer at lists.osgeo.org <qgis-developer at lists.osgeo.org>
> Subject: Re: [QGIS-Developer] Project loader profiler Postgres Layers
>
> Hi Rémi,
>
> During the provider creation, a lot of SQL requests are made to check a lot of thing even if the use estimated metadata is checked :
> * Fields list
> * geometry type
> * primary key
> * extent
> * capabilities (read, insert, update, delete)
>
> You can take a look at these PRs to have an idea on all the SQL request made at the creation :
> * https://github.com/qgis/QGIS/pull/49440
> * https://github.com/qgis/QGIS/pull/50186
>
> Regards,
> René-Luc
>
> Le 16/11/2022 à 09:55, Julien Cabieces via QGIS-Developer a écrit :
>
>
>
> Hi Remi,
>
>
>
> Which profiler are you talking about ?
>
>
>
> Did you try to use the the new Debugging/Developement tool ? It's new
>
> since QGIS 3.26 and will give you the list of requests and the time
>
> spent for each one when loading a project/layer or opening the attribute
>
> table.
>
>
>
> Regards,
>
> Julien
>
>
>
>
>
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