Why does deleting a folder containing a lot of files take so much time to sync?

[hiq]

Hi,

I have (had) a folder “2020” containing a lot of (small) files. 2020 being over, I proceeded to delete this folder.

Syncthing then synced this folder with my mobile device (Android). But it looks like every file is synchronized. In practice it means that it took something like 5 minutes to synchronize the deletion of 50k files, with the counter of the number of files to sync slowly decreasing over time.

I would expect Syncthing to realize that the folder is no longer here locally, so the folder should also be deleted there, which should be faster than deleting every single file.

Why doesn’t it seem to work this way?

[AudriusButkevicius]

That’s simply not how the process works.

We can’t guarantee that you don’t have ignored files in there, or that the other side actually had all files you have (you might have some files the other side didn’t, so deleting the directory would lead to data loss), hence the only way you can do this safely and consistently is on a file by file basis.