Question

Here’s the story, my heroku site was originally using the 5mb shared postgres db with no problems. I had a valid SHARED_DATABASE_URL and no DATABASE_URL

Then I added a config var by doing

heroku config:add DATABASE_URL=non_existing_database_just_for_fun

Just to see if it would switch from the shared db to this new one I just set. It did just that, and promptly crashed my app as expected since no valid database was found.

Then I did heroku config:remove DATABASE_URL hoping to get my site back to normal. But now it keeps crashing and never succeeds in starting up. If I do a heroku config I see that I still have a valid SHARED_DATABASE_URL and no DATABASE_URL but the site still wont work.

I did get it working by setting up DATABASE_URL to match SHARED_DATABASE_URL but I’d like to get it back to how things were originally, the site working without needing DATABASE_URL. Any ideas no how I can get things back to the way they were short of having to reinstall my site?

Answer 1

DATABASE_URL is the key that Heroku expect you to use for your database connectivity. They will not touch this value unless you ask them to (aside from initial setup).

The SHARED_DATABASE_URL is the URL of the shared database that they have provided to you.

By default, Heroku set your DATABASE_URL to match your SHARED_DATABASE_URL.

I’m not entirely sure why would would want your application to not have a DATABASE_URL, as that’s what’s used. If you look at the bottom of this, you can see what they do with your config/database.yml and how it affects your application.