We both learned something new today. Looks like this is what you want in combination with using an in memory database.

I've been doing a handrolled in memory cache layer to speed data access, but with this, I can just call the db directly and then periodically sync to disk, redis rdb style. Sqlite is a staggeringly good piece of technology!

https://www.sqlite.org/backup.html

In Python you just have to open the special file name “:memory:” to get a memory-based db. I don’t remember what the raw SQLite incantation is (or if it’s different). Also, pay attention to “ATTACH” - it’s the way to use multiple databases (file and/or memory) while still letting SQLite handle it all (e.g. join a memory db to a file db, insert result into 3rd file db - all without having to look at records in your own code)

It's the same in plain sqlite.