Testing Calibre's limits (not a question!)

I wanted to test Calibre's limits in terms of handling an absurdly large number of books. I'm an engineer and can't really help it.

I created a new Calibre library and kept adding a set of ~1500 books again and again, ignoring duplicates, until I started seeing a noticeable slowdown in Calibre. This is by no means a typical situation, no one has that many books. Ultimately, Calibre begins to struggle around the 30,000 book mark.

Now I know, and now you know too!