Faster PostgreSQL during development

Buried in PostgreSQL’s documentation is this chapter: Non-Durable Settings. To quote:

Durability is a database feature that guarantees the recording of committed transactions even if the server crashes or loses power. However, durability adds significant database overhead, so if your site does not require such a guarantee, PostgreSQL can be configured to run much faster.

In your development environment, you probably don’t need that guarantee.

Settings

Adjust these settings:

fsync = off
full_page_writes = off
synchronous_commit = off

There are more settings listed in the documentation, but these three are the most important ones. You can also specify them on the command line:

postgres -c fsync=off -c full_page_writes=off -c synchronous_commit=off

Usage in Docker Compose:

services:
  db:
    image: postgres
    # Relax durability guarantees to improve performance during development.
    # See: https://notes.dt.in.th/PostgresDevConfig
    command:
      - postgres
      - -c
      - fsync=off
      - -c
      - full_page_writes=off
      - -c
      - synchronous_commit=off
    # (...)

# Monkey-patch ActiveRecord::Migrator#migrate to log the start time and finish time of each migration.
module MigratorLogging
  def migrate
    start_time = Time.now
    super
    finish_time = Time.now
    File.open(Rails.root.join('log', 'db_migration.log'), 'a') do |f|
      f.puts "Migration started at #{start_time} and ended at #{finish_time}. Migration took #{finish_time - start_time} seconds."
    end
  end
end
class ActiveRecord::Migrator
  prepend MigratorLogging
end