Just wanted to add another’s scenario where postgresql has been useful to me. Functions. There are cases where you have expensive operation(s) that reference a lot of persistent data. Even without massive traffic these operations can be prohibitively expensive in the middleware. Leveraging database functions can be a massive performance improvement (100x + for me), especially if your middleware is slow (e.g. rails).
I’ve used SQLite in production once and it worked great. But that was a very simple app. For more complex (but not always higher traffic) I’m leaning more and more on postgresql and less on my middleware, like moving business logic to the database when it makes sense.
