But all I know is that they had been throwing hardware on a MySQL install to make it work better.
He migrated them to postgres and they got much better performance and could get away with less hardware than they had with mysql.
That was as much detail that I remember. Keep in mind I said by sheer luck I became a fanboy. Not by experience and competence. That came later.
A database for competent users can be amazingly simple and fast. But the Market Has Spoken, loud and clear: databases must absorb an indefinitely large amount of complexity to make the job of app writers a tiny bit easier.
I think there are definitely cases where DB needs to compensate for bad architecture, but then even competent developers can profit from the flexibility of being able to ad new features ad hoc to an existing db schema/architecture and the DB just magically bailing them out.