[Uatschitchun]

Yes, sources suggestion was helpful indeed, as it allows folder type node with using the sourceid of a combined source.
One question here. If my sources are for instance
/media/audioplay/comedy
/media/audioplay/audiobooks
is it ok to add a single path node
/media/audioplay/
or should it better be a multipath source of the single sources above?

Would adding the sourceid filter option for musicdb://years,genres and recentlies speed up things?

I thought that it's about choking in regards to the genre query filtered by path. Together with the slowness, it creates wrong (empty) results.

If you'd like me to test, you know how to reach me!

Conclusion until now:
Filter type queries on genre by path are slow as hell
Folder type queries work for every item that allows sourceid filtering (artists, albums). A list of possible filter options for folder type queries (musicdb://...) would be glorious @Dave!