ALCON, We are processing data at 4cm resolution from 4000 ft altitude that gives me a DSM Ortho of about 800 GB -1.3 TB depending on the bit depth. My folders have a rile count of over 88,000 Tiles @ 2048 X 2048 with a GSD of ~.076 depending on the processing you are doing I am guessing you can get 8-16 tiles per thread when doing a mosaic operation or even an export. No mention of the tool being used was given, I am doing a lot of reprojects on that file base I described and if I go into multi-thread mode I know it will kick that number up.
Again, I am used to what I see from another tool that uses the GDAL Library for processing and it does get up over 140 threads when it is doing it processing From: chris hermansen <[email protected]> Sent: Saturday, July 30, 2022 3:57 PM To: Mike Stanton <[email protected]> Cc: Greg Troxel <[email protected]>; qgis-user <[email protected]> Subject: Re: [Qgis-user] excessive threads? 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 <[email protected]<mailto:[email protected]>> 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 <[email protected]<mailto:[email protected]>> On Behalf Of chris hermansen via Qgis-user Sent: Saturday, July 30, 2022 2:37 PM To: Greg Troxel <[email protected]<mailto:[email protected]>> Cc: qgis-user <[email protected]<mailto:[email protected]>> Subject: Re: [Qgis-user] excessive threads? Greg and list On Sat, Jul 30, 2022 at 10:38 AM Greg Troxel via Qgis-user <[email protected]<mailto:[email protected]>> 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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