Code review comment for lp:~stub/charms/precise/postgresql/docs

Ah, you're right that the mongodb charm isn't dealing with a backup / restore scenario, so the particular trick isn't sufficient in this case. Not changing the password on every relation-change event still seems like it could be less confusing for the admin, though it might also encourage too much reliance on the password being stable and cause the problems you mentioned in the docs during a restore.

The mongodb charm also uses the unit number as part of the stable username, which would change during a restore operation. I assume that if a given service has multiple units for scaling, they would want to share the same database credentials, allowing your idea for stable usernames to work?