Altering DATABASE_URL is *not* recommended

[msakrejda]

This section makes recommendations that are at odds with what we at Heroku recommend. We do need to update DATABASE_URL occasionally (most notably in case of a hardware failure), and when that happens, we do not account for the existing value, meaning that any and all query string parameters are lost. I've started a discussion with my colleagues on whether we can do better here, but in the meantime, this is not a good recommendation, given that your DATABASE_URL may be replaced by us if necessary.

[eprothro]

Fine with me, happy to pull that portion of the config code and section in the wiki.

I inferred that was a Heroku-approved recommendation, as the database.yml y'all inject includes the same code to apply query params from the DATABASE_URL to the database connection config.

Thanks for letting me know.

[eprothro]

I've added a note that this is not recommended to that wiki page.

If this support is removed from the Heroku build behavior, I'll pull it from the recommended Heroku configuration. For now, it seems best to at least mimc the behavior of the primary database connection configuration. Happy to discuss if you disagree, thanks again.

[msakrejda]

Awesome, thanks for the quick response. I'll admit our behavior with respect to DATABASE_URL and database.yml is a little schizophrenic--technically, the add-on provider contract allows the provider to change the URL (actually hardware failure is less common--consider something like a pg:credentials --reset), but the build packs don't really consider that.

We could probably just do a substring replacement, rather than changing the string wholesale, but we're moving to a model where users will have no control over config vars added by an add-on, but we'll provide some principled way to deal with database query string issues before we do that.

[thiagopradi]

So, closing this issue. any problems, please reopen.