dirty_tracking_benchmark.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  gem "rails", github: "rails/rails"
  gem "sqlite3"
  gem "benchmark-ips"
end

require "active_record"

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")

ActiveRecord::Schema.define do
  create_table :users, force: true do |t|
    t.string :name
    t.timestamps null: false
  end

  create_table :topics, force: true do |t|
    t.string :title
    t.integer :user_id
    t.timestamps null: false
  end
end

class Topic < ActiveRecord::Base
  belongs_to :user
end

class User < ActiveRecord::Base
  has_many :topics
end

user = User.create!(name: "user name")
topic = user.topics.build(title: "topic title")

Benchmark.ips do |x|
  x.report("changed?") { topic.changed? }
  x.report("changed") { topic.changed }
  x.report("changes") { topic.changes }
  x.report("changed_attributes") { topic.changed_attributes }
  x.report("title_change") { topic.title_change }
  x.report("title_was") { topic.title_was }
end