Bug 501703

Summary:	Krusader (and Dolphin) are extremely slow when browsing sftp fuse mounted remote locations
Product:	[Frameworks and Libraries] frameworks-kio	Reporter:	PhobosK <phobosk>
Component:	general	Assignee:	KIO Bugs <kio-bugs-null>
Status:	REPORTED ---
Severity:	normal	CC:	john.kizer, kdelibs-bugs-null
Priority:	NOR
Version First Reported In:	6.12.0
Target Milestone:	---
Platform:	openSUSE
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description PhobosK 2025-03-18 19:21:09 UTC

SUMMARY
If one mounts an sftp remote location using fuse (for example: root@[XXXXXX]:/ on /mnt/sshfs/remote_location type fuse.sshfs (rw,nosuid,nodev,relatime,user_id=1000,group_id=100)), when browsing it with krusader/dolphin the process is extremely slow. Also a lot non-responsive.
If the mounted remote location is from the local network, the browsing is not that slow, but still slow.
This used to work without problem a few KDE subversions ago (cannot say when it broke).
At the same time, using command line (ex. ls -la), Midnight Commander (mc), Double commander etc NON KDE applications, the same remote location browsing has no problem.

STEPS TO REPRODUCE
1. Mount an sftp remote location (one from outside your local network) using fuse tools.
2. Open krusader or dolphin and try to go to the locally mounted remote /etc folder (which has a lot of subfolders and files)

OBSERVED RESULT
The browsing is very slow and krusader/dolphin windows that show the list of folders are freezing a lot for more than 2-3 seconds before showing the next batch of the list. Opening files and other actions are also extremely slow.

EXPECTED RESULT
All to work smoothly since KDE should see the fuse mounted folders as local.

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20250316
KDE Plasma Version: 6.3.3
KDE Frameworks Version: 6.11.0
Qt Version: 6.8.2

ADDITIONAL INFORMATION
- This used to work perfectly well
- It is not a network or ssh fuse problem, because all other non KDE apps work fast as if the remote location is local (as it is expected)
- if the fuse mounted fs is in the local network, the browsing is not that slow, but is still noticeable slow.
- Looks a lot like bug#178678 but still somewhat different and newer

Comment 1 John Kizer 2025-03-28 06:38:30 UTC

Hi - good observation on the similarity to https://bugs.kde.org/show_bug.cgi?id=178678 - I'm actually not seeing the difference in the core situations between this report and that one, can you please help me understand what's somewhat different between the two? Thanks!

Comment 2 PhobosK 2025-03-31 05:28:12 UTC

Main difference I think is that browding mounts from local network is faster and mostly not so noticeable delays....
Remote mounts on the other hand - do show very slow operations.
In my setup both local and remote mounts are using 1Gb network speed (optic connection)

Another difference is that all non-KDE apps have no problem with the mounts (ex. ls, mc, Double commander, Nautilus etc) - no delay even 1 s...