Just because I create a derivative work of an (A)GPL project does not immediately require me to publish those changes. Only if I distribute the work, I also nee

Just because I create a derivative work of an (A)GPL project does not immediately require me to publish those changes. Only if I distribute the work, I also need to distribute the changes along with it. While a derivative work of Postgres is created, it is not "distributed" (in the sense of the AGPL). The web application is, which I do not consider a derivative work of Postgres in the general case. If you implement a feature in Postgres and have a web application that is practically just a wrapper around this one, new feature, then that could be considered a derivative work. But I'd say that's a far stretch.