Rails Multiple Databases with Environment Variables

2026-01-14T00:00:00-05:00

When deploying Rails with multiple databases (Solid Cable, Solid Cache, Solid Queue), you can configure each database using prefixed environment variables.

The naming convention is {DATABASE_NAME}_DATABASE_URL:

# config/database.yml
production:
  primary:
    url: <%= ENV["DATABASE_URL"] %>

  cache:
    url: <%= ENV["CACHE_DATABASE_URL"] %>

  cable:
    url: <%= ENV["CABLE_DATABASE_URL"] %>

  queue:
    url: <%= ENV["QUEUE_DATABASE_URL"] %>

Then set the corresponding environment variables:

DATABASE_URL=postgres://user:pass@host/myapp_production
CACHE_DATABASE_URL=postgres://user:pass@host/myapp_cache
CABLE_DATABASE_URL=postgres://user:pass@host/myapp_cable
QUEUE_DATABASE_URL=postgres://user:pass@host/myapp_queue

This keeps credentials out of your repo. It also lets each database live on its own host, or even a different engine entirely, like SQLite for cache while primary stays on Postgres.

Adam Daniels | Notes

Rails Multiple Databases with Environment Variables