Rollback, Followers, and Forks - Learning Heroku Postgres - page 131

Creating and managing follower databases
The follower feature is enabled for the plans in the standard, premium, and enterprise tiers.
You can check whether your database is enabled to use followers through the heroku
pg:info command:
$ heroku pg:info --app your-app-name
=== HEROKU_POSTGRESQL_CHARCOAL_URL (DATABASE_URL)
…
Fork/Follow: Available
…
A follower database must be created from a database that allows us to read and write. Usu-
ally, the follower database is created from DATABASE_URL . You cannot create followers
in cascade from another follower database.
The creation of a follower database consists of adding a new database through Heroku add-
ons and the use of the --follow flag and the database URL from which the follower
must be created:
$ heroku addons:add heroku-postgresql:standard-2 --follow
HEROKU_POSTGRESQL_[COLOR]_URL --app your-app-name
Adding heroku-postgresql:standard-2 on your-app-name...
done, v245 ($200/mo)
Attached as HEROKU_POSTGRESQL_BLACK_URL
Follower will become available for read-only queries when
up-to-date
Use `heroku pg:wait` to track status.
Use `heroku addons:docs heroku-postgresql` to view
documentation.
In the preceding command, heroku-postgresql:standard-2 informs us about the
type of plan that will be used for the follower database. You can select the plan that best
suits you, and through https://addons.heroku.com/heroku-postgresql , you can see all the
available plans.