Bug 461394

Summary: Listing items in a folder is unusable slow (with all previews disabled)
Product: [Applications] dolphin Reporter: Nathan Shearer <kde-20091112>
Component: view-engine: generalAssignee: Dolphin Bug Assignee <dolphin-bugs-null>
Status: REPORTED ---    
Severity: normal CC: kde-20091112, kfm-devel
Priority: NOR    
Version: 21.12.3   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description Nathan Shearer 2022-11-04 03:23:26 UTC 
STEPS TO REPRODUCE
1. Set your Dolphin view mode to Compact and disable all Previews in Settings->Configure Dolphin->General->Previews
2. Put a 1000+ songs in one folder.
3. Open that folder in Dolphin and attempt to navigate to one item.

OBSERVED RESULT
Dolphin will start listing the directory and inspecting every single item (probably to draw an icon). This radically slows down the simple process of listing the items in the directory so much that a folder with over 1000 items is completely unusable. This is significantly worse on even a nfs4 mount over local gigabit LAN.

EXPECTED RESULT
List the items as quickly as `ls --color=never`. For extra detail like Previews and icons, do this in the background without disrupting the user. Perhaps prioritize items that the user has selected, then within view of the window, then the rest in the folder.

SOFTWARE/OS VERSIONS
Operating System: Gentoo Linux
KDE Plasma Version: 5.23.5
KDE Frameworks Version: 5.92.0
Qt Version: 5.15.3
Kernel Version: 5.15.61 (64-bit)
Graphics Platform: X11
Processors: 8 × 11th Gen Intel® Core™ i7-1165G7 @ 2.80GHz
Memory: 31.1 GiB of RAM
Graphics Processor: Mesa Intel® Xe Graphics

ADDITIONAL INFORMATION
Note that `ls` exhibits the same behaviour when --color is enabled. Run `ls --color=never` and this is how Dolphin should perform. Quickly.