Bug 474135 - Parallel Flatpak downloads can saturate a slow network and render it unusable
Summary: Parallel Flatpak downloads can saturate a slow network and render it unusable
Alias: None
Product: Discover
Classification: Applications
Component: Flatpak Backend (show other bugs)
Version: 5.26.1
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: Plasma Bugs List
Depends on:
Reported: 2023-09-04 12:53 UTC by Ellie
Modified: 2023-09-07 14:51 UTC (History)
4 users (show)

See Also:
Latest Commit:
Version Fixed In:


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Description Ellie 2023-09-04 12:53:25 UTC
NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols.
See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports
Parallel downloads as a default can cause everything to fail on slower connections without any detection mechanism to downgrade to sequential downloads when it gets too laggy.

1. Use slow internet
2. Wait until you have 10+ different flatpak app updates sitting in discover waiting to be updated
3. Press button to update them all

All downloads seem to start at once, at least the progress bar suggests so, and soon enough, your entire internet will die, all downloads will fail, and everything will be a complete mess.

Downloads are either done sequentially by default, or whatever does parallel downloads detects if too many fail and switches over to sequential downloads. (However, the latter is IMHO still an inferior solution because it can greatly impact other users of the same wifi and cause lots of issues anyway on slow connections.)

Linux/KDE Plasma: SteamOS Holo 3.4.10 Builid 20230831.1, kernel 5.13.0-valve37-1-neptune
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 5.99.0
Qt Version: 5.15.6, built against 5.15.6

Since I'm not entirely sure if the problematic component initiating the parallel downloads thoughtless is flatpak itself or KDE discover, there's also a downstream ticket here: https://github.com/flatpak/flatpak/issues/5162 If someone here knows on which side the problem lies I'd be glad to hear so I can close the incorrect one.
Comment 1 Bug Janitor Service 2023-09-04 13:33:53 UTC
Thank you for the bug report!

Please note that Plasma 5.26.1 will not be supported for much longer by KDE; supported versions are 5.27, and 5.27 or newer.

Please upgrade to the latest version as soon as your distribution makes it available to you. Plasma is a fast-moving project, and bugs in one version are often fixed in the next one.
Comment 2 Nate Graham 2023-09-05 19:55:28 UTC
> your entire internet will die

Can you clarify what this means exactly? The connection goes offline for every app, or the individual downloads simply proceed so slowly that they never complete or time out?
Comment 3 Ellie 2023-09-06 06:48:07 UTC
All connections timeout but not just for KDE Discover, because it clogs the wifi too much. So the internet connection in theory is still available, but in practice it goes offline for every app.
Comment 4 Nate Graham 2023-09-06 16:44:17 UTC
Comment 5 Ellie 2023-09-06 16:59:01 UTC
My apologies, I gave the wrong github issue link for the parallel download ticket there: https://github.com/flatpak/flatpak/issues/5231

Did I understand correctly however that the parallel queuing seems to be happening on the KDE Discover side, and isn't some inherent flatpak backend feature? In that case it would make sense for me to close the flatpak issue.
Comment 6 Nate Graham 2023-09-07 14:51:44 UTC
It would appear there things we can do on our side to make this better, yeah.