Using a managed service is a very attractive proposition. You are offloading a heck of a lot of worry, especially when it comes to something as complicated and, let’s face it, specialized as a database. Someone else will set it up for you, and back it up, and keep it running, without you having to worry too much about it. However, there are downsides. You can only get what the manager is offering. Often that’s good enough. But needs change, and I have often seen people start with managed services, only to find that they want more than they can get that way.
Just yesterday I received a complaint that the Redis Foreign Data Wrapper (which I have done a lot of work on) is not available on Amazon RDS. And that’s completely understandable. Amazon only provides a limited number of extensions, and this isn’t one of them. At least one other managed service, Heroku, does offer this extension, but there are others it doesn’t offer.
So the lesson is: choose your managed service, or even whether to use a managed service at all, very carefully, taking into account both your current needs and your likely future needs.