We need limit the amount of previews generated at once when listing images in Files

[ariselseng]

Background: ariselseng/camerarawpreviews#31

User has encryption enabled, lists files in the Files app in details mode, scrolls to the bottom, and triggers hundreds of previews being generated. The problem gets even worse due to encryption + big raw files (enabled previews with my app). Preview generator is not the answer due to encryption.

We should make sure not more than x amount of images are being generated preview for at the same time.

[phpbg]

it would be interesting if you can test this pull request to see how it improves (or not) : #17028

Indeed, when you browse the files for the first time, two previews are generated for each picture.
I did this patch to generate only the required preview, and saw very interesting results.

I'm being told by nextcloud guys that those two previews are used to improve speed when generating previews from big raw files (they generate a big preview that should be smaller than your raw file, so it should be faster next times).

There are no measurements for this, but IMO generating two previews has a very bad impact on first load (what you are doing here).

Please test it and report back...

[phpbg]

Also, as a short term solution I reduced my php-fpm pool size to prevent overload

[kesselb]

We should make sure not more than x amount of images are being generated preview for at the same time.

I agree we should do something like this.

[phpbg]

We should make sure not more than x amount of images are being generated preview for at the same time.

I agree we should do something like this.

Do you mean on the server, globally, or on the client side (javasript) ?