> A very long time ago (circa 2000) there were basically 2 databases that worked for use cases where you needed high availability and vertical scalability

... and both of them were Postgres.

I used it in the late 90s for the backend for websites written in PHP3, but everyone said this was ridiculous and silly and don't you know that everyone's using the MySQL thing.

So I used this MySQL thing, but by about 2005 I'd gone back to powering my lawnmower with a 500bhp Scania V8 because I just preferred having that level of ridiculous overkill in an engine.

Nowadays? Key/Value store in RAM is probably fine for testing -> Sqlite is often Good Enough -> Ah sod it, fire Postgres into a docker container and warn the neighbours, we're going down the Scanny V8 route yet again.