You're right, I forgot about this one. I think because when I last looked at it, the MVCC part wasn't very straightforward to me.

They are probably no longer just educational dafter implementing MVCC.

Thanks! I'd also like to see a MVCC implementation because that would shed some light on how mysql works. I'll add MVCC to the future improvements section

What other educational databases are you looking at? Curious in case I'm missing any of them.

RisingLight, SimpleDB by Edward Sciore, SimpleDB for the MIT course are the main ones that come to my mind immediately. I forgot that Erik Grinaker's ToyDB implements MVCC but I remember it being hard to grok and not very straightforward.

There is also BusTub from CMU which I stumbled upon earlier today:

https://github.com/cmu-db/bustub

LMDB implements MVCC and is pretty easy to read, the implementation is very tiny.