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Switch to PostgreSQL

Published: September 22, 2020

This is part of The Annotated Guide to a New Rails App, a list of recommendations to make developing your Rails app more productive and joyful.

In this article, we are talking about switching to PostgreSQL.

When

I recommend switching to PostgreSQL before creating your first production environment.

Why

Rails uses SQLite as the database by default because it is fully-contained; there is no server to manage and the data is kept in a local file.

However, SQLite is not suitable for most production environments; PostgreSQL is a much better choice.

PostgreSQL should also be used in development in order to maintain dev/prod parity.

How

To switch to PostgreSQL:

  1. Install PostgreSQL on your development machine and make sure that it is running.
  2. Change the database gem. In Gemfile, replace gem 'sqlite3' with gem 'pg'. Then run bundle to update your gems.
  3. Change the database adapter. In config/database.yml replace the adaptor: adapter: sqlite3 with adapter: postgresql.
  4. Change the database names in config/database.yml. Use projectname_development for the development database, projectname_test for the test database, and projectname_production for the production database.

Test that this works by running rake db:create.

Alternatives

Large and successful projects are also run on MySQL. In the past, MySQL had some severe limitations but those issues may be papered over by Rails or fixed entirely.

I wouldn’t risk it, but others certainly do.