How to reset PG Database on Heroku (for Rails app)?

heroku_pg_db_reset.md

It's important to note that running this reset will drop any existing data you have in the application

How to reset PG Database on Heroku?

• Step 1: heroku restart
• Step 2: heroku pg:reset DATABASE (no need to change the DATABASE)
• Step 3: heroku run rake db:migrate
• Step 4: heroku run rake db:seed (if you have seed)

One liner

heroku restart; heroku pg:reset DATABASE --confirm APP-NAME; heroku run rake db:migrate

Note 1

Heroku doesn't allow users from using rake db:reset, rake db:drop and rake db:create command. They only allow heroku pg:reset and rake db:migrate commands.

More info: https://devcenter.heroku.com/articles/rake

Note 2

If you have more than 1 remote, append --remote [your_remote_name] like this:

heroku run rake db:migrate --remote dev (dev is example remote here)

What if you want your app to reset itself?

Imagine you have some type of demo that needs to reset itself once a day.

1. Install the Database Cleaner Gem and make sure you make it available for the production environment.

2. Create a lib/tasks/scheduler.rake file that looks similar to this

desc "This task is called by the Heroku scheduler add-on to reset the demo"
task :reset_demo => :environment do
  puts "Cleaning Up The DB..."
  DatabaseCleaner.strategy = :truncation
  DatabaseCleaner.clean
  puts "Seeding the DB again..."
  Rake::Task["db:seed"].invoke
  puts "done!"
end

3. Commit and do git push heroku master

4. Add the following ENV variables to your Heroku app to disable the Database Cleaner Safeguards. You can do this by logging into your Heroku account.

DATABASE_CLEANER_ALLOW_PRODUCTION=true
DATABASE_CLEANER_ALLOW_REMOTE_DATABASE_URL=true

5. Test it by running heroku run rake reset_demo

6. Use the Heroku Scheduler Add-on to program how often should the rake task be executed.

I have the following error :

• [my app] has no database

but i have a cleardb database for a mysql app

oooh thanks!

Wow, works perfect! Many thanks!

It's important to note that running this reset will drop any existing data you have in the application.

Thank you!

Thank you!

Thank you.
This solution, in addition with some other, helped me solve my issue.
However, I lost some data in the process.
Everything else came out very fine

I've open this like 10 times in the last month. Super useful. Thank you.

Thank you for putting this together, handy and helpful resource <3

Thanks! It works for my demo proposes when data itself is not nessesary.

If you find yourself where you cannot re-run migrations as the code has changed since they were written you can do the following to reload the schema:

1. heroku pg:reset DATABASE
2. heroku run rails db:environment:set RAILS_ENV=production
3. heroku run DISABLE_DATABASE_ENVIRONMENT_CHECK=1 rails db:schema:load
4. heroku run rails db:seed

Step 2 is honestly new to me but from the limited reading it sets the DB's environment to production so I assume it knows the proper database.yml values to load. Either way it's required before step 3 will run and because it is a mutation operation on a prod env database you have to manually allow it via the ENV var.