How to Reset Heroku Postgres Database and Why It Keep Fails

Photo by Anders Jildén on Unsplash

Dropping database production is not your usual practice. Surprisingly, it is not straightforward for it’s for reason. Learn the hard way.

Too Long, Didn’t Read

Run this one-liner command.

heroku restart && heroku pg:reset DATABASE && heroku run rake db:migrate

Step 1: heroku restart (make sure it has no process run)
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)

Too Long, Read Anyway

I have Rails app, so it should be as simple as…

cd my_rails_app && heroku pg:reset DATABASE

rake db:reset

But, the reality is a little harder.

I have a Rails 4 app, using Postgres 9.4, Heroku Cedar stack. There are two databases: one is the production database, another one is for staging. Generally, this is a good practice to have a staging environment that is equivalent to production. So that I should have a staging database on Heroku.

When pushing to staging, I want to reset the database to ensure it’s exactly the same as production. So I run the command above. It should be like:


heroku pg:reset DATABASE

But it just not works.

It certainly works locally. It is not in local development. It is live in the production environment, even only the staging server.

The story behind of reset

I have a staging server (running in a production environment) and it was simply deployed in Heroku. No reason behind it. It was quite easy to deploy and I also Heroku provide almost-production-running-like app without hassle with as simple as command heroku create

Heroku is chosen because Heroku simply provides an almost-production-running-like app without hassle. One day I need to reset the database because Heroku only provides 10.000 free rows.

Rails that prevents data wipeout.

When I run heroku run rake db:drop on heroku CLI, It will given this kind error messages.

ActiveRecord::ProtectedEnvironmentError: You are attempting to run a destructive action against your 'production' database.
If you are sure you want to continue, run the same command with the environment variable:
DISABLE_DATABASE_ENVIRONMENT_CHECK=1

Okay, I get it. See Rails commits about prevent destructive action on production databaset, it’s handy feature :

Preventing destructive action on production database.

Let’s run heroku run rake db:drop DISABLE_DATABASE_ENVIRONMENT_CHECK=1 and try my luck.

And what happens is another errors.

Database 'des74ei48mf9s6' does not exist

Not sure for this one.

Make sure it has no process run.

heroku restart

Heroku apps do not have permission to drop and create databases.

It seems like not all Rake features are supported on Heroku. Heroku apps do not have permission to drop and create databases.

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.

The following is a list of known limitations see: Heroku Limitations

Summary

Dropping the production database is not your usual performance. Despite the non-straightforward step, it is made to ensure and double-check your action.

Are you sure you really want to destroy the production database?

Thanks for reading.