[Qgis-user] excessive threads?

[chris hermansen]

Mike and list,

Mike, would you please explain why the surface area would be related to the
number of threads?

1000 square miles or ~ 250.000 hectares in my units is big but not huge. We
have a 7 million hectare vegetation inventory we're updating now.

Do you have a bunch of small tiles? Are you thinking that 1 tile = 1 thread?

On Sat, Jul 30, 2022, 12:46 Mike Stanton <mfstanton at geospan.com> wrote:

> Chris, it really depends on how large your project is. Some of my projects
> cover 1000 sq miles.  Usually I don’t use QGIS directly for that, I break
> it down to smaller pieces.
>
>
>
> *From:* Qgis-user <qgis-user-bounces at lists.osgeo.org> * On Behalf Of *chris
> hermansen via Qgis-user
> *Sent:* Saturday, July 30, 2022 2:37 PM
> *To:* Greg Troxel <gdt at lexort.com>
> *Cc:* qgis-user <qgis-user at lists.osgeo.org>
> *Subject:* Re: [Qgis-user] excessive threads?
>
>
>
> Greg and list
>
>
>
> On Sat, Jul 30, 2022 at 10:38 AM Greg Troxel via Qgis-user <
> qgis-user at lists.osgeo.org> wrote:
>
>
> (I realize excessive is relative.  Back when I was young, we didn't have
> any threads at all....)
>
> My desktop is NetBSD 9, I ran out of threads, and found that qgis 3.22.8
> was using 157 threads, much more than I expected.
>
>
>
> [stuff deleted]
>
>
> I really don't understand:
>
>   What is qgis using threads for?
>
>   Do others see large (100 or so, vs 10) thread counts?
>
>   Why are there 157 (really, why are there more than about 10-20)?
>
> Seems kind of surprising to me as well.  I get that some applications
> could benefit by parallel execution, and of course separating rendering
> from file or other I/O seems reasonable, but 157 is a lot of threads for
> just reading data and visualizing it.
>
>
>
> As far as I know, PostgreSQL doesn't even use threads.  See for example
> this discussion
> https://dba.stackexchange.com/questions/251935/number-of-worker-threads-available-in-postgresql
>
>
>
> About SQLite I have no idea.
>
>
>
> Does it seem like you have one thread per layer for reading plus one for
> rendering plus one for user  input?
>
>
>
> --
>
> Chris Hermansen · clhermansen "at" gmail "dot" com
>
> C'est ma façon de parler.
>
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