> Can't we just let stuff work? I'm no fan of MySQL, but can't we admit that a ubiquitous and battle-tested piece of technology, applied to a canonical use case, on tiny data under near-ideal circumstances, is probably going to work just fine?

I call that "separation of error-domains", meaning trying to find interfaces where you can separate off parts of your application, so debugging gets easier:

Is the bug in the database, or in our code?