Doing a backup over my roughly 30GB, 30’000 profile (all living on a fast SSD) with filter group default excludes takes roughly 12 minutes, at least 80% of which is spent counting files (counter goes up by about 50-100 files per second.
If I kick out filter group default excludes and just a have a bunch of excluded directories otherwise, it goes down to 2-3 minutes, most of which is spent checking backend files (which I guess cannot be avoided given duplicati’s architecture).
It definitely feels like there is something seriously wrong in the filter group code.