SUMMARY Thumbnail cache (du -h ~/.cache/thumbnails|sort -h) can grow to around 10GB+ https://forums.debian.net/viewtopic.php?t=154081 by default "keep only thumbnails for the folders visited in last 3 months and remove rest" "this really ought to be a configurable setting/feature with Dolphin" Impact: 1. cleanup thumbnails for files that no longer exist. 2. avoid taking too much disk space for the files that are not really used in months Maybe the cleanup can be done if the drive usage exceeds some threshold like 80% or regularly, but rarely (during shutdown etc.) not to cause slowdowns due to too many IO operations. Some file systems/mountpoints does not use atime. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Debian 12, all stable KDE Plasma Version: 5.27.5 KDE Frameworks Version: 5.103.0 Qt Version: 5.15.8
I agree that an option for this would be great, but I currently don't see how one would implement this. The information if a thumbnail was used would need to be saved, but storing information on disk any time a thumbnail is loaded seems like a huge number of writes and disk wear for very little gain. We don't want to stress the disk when a user is only navigating between folders.
If Dolphin already creates some ram based index (i am unsure how big it can be for lets say 50 million image files) of of files and its thumbnails, maybe next parameter of such index may be last date+time when the file/thumbnail parent folder has been accessed. Or this information be stored somewhere else. And the thumbnail garbage collector would process folders based on its last access date/time and delete its child thumbnails if the access date/time is too old. Sorry, I know nothing about programming.
(In reply to Petr N. from comment #2) > If Dolphin already creates some ram based index The data needs to be stored in permanent storage eventually so we still would have the issue of extra wear on the hardware just by navigating the file system. > date+time when the file/thumbnail parent folder has been accessed Saving the information only once per parent folder would not work with the current implementation because we do not store thumbnails by parent folder. The stored thumbnails do not contain information about where their respective file is. The thumbnail is stored per file so no matter where the file is encountered, we will be able to load the thumbnail. There might also be privacy concerns if from the thumbnails alone one could identify both when the file was last opened as well as where the file is stored. In any case I will mark the bug report as CONFIRMED because I think it is a fair request even if I don't know how one would proceed here.