I can confirm that, in the current release, there is a problem with large databases and the library tab.
However i do not have any statistics on a maximum amount and I’m not aware of any fix.
Sorry that i cant be of any more assistance in this matter…
I did have a library of about 4000 songs. My HDD crashed, so I’m beginning collect my music again. I do not have a big library at the moment, just few hundreds, and the library tab doesn’t show anything. When I installed Volumio in the beginning, the library tab did work with the 4000 songs. But suddenly it didn’t work any more. Installed Volumio again, and it worked for some time, but then again it didn’t. So I don’t think it is large library related.