transaction_memory_usage.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", "< 2.8"
end

require "active_record"
require "minitest/autorun"
require "logger"

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

ActiveRecord::Schema.define do
  create_table :coupons, force: true do |t|
    t.text :name
  end

  create_table :sites, force: true do |t|
    t.text :name
  end

  create_table :products, force: true do |t|
    t.text :name
  end

  create_table :coupons_sites, force: true, id: false do |t|
    t.references :coupon
    t.references :site
  end

  create_table :coupons_products, force: true, id: false do |t|
    t.references :coupon
    t.references :product
  end
end

class Coupon < ActiveRecord::Base
  has_and_belongs_to_many :products
  has_and_belongs_to_many :sites
end

class Product < ActiveRecord::Base
  has_and_belongs_to_many :coupons
end

class Site < ActiveRecord::Base
  has_and_belongs_to_many :coupons
end

require "objspace"
require "active_support/core_ext/numeric/conversions"

puts
puts
puts "Memory usage: #{ObjectSpace.memsize_of_all.to_s(:human_size)}"

Coupon.transaction do
  1.upto(250_000) do |i|
    Coupon.create!

    if i % 500 == 0
      GC.start
      puts "Created #{ i } coupons..."
      puts "Memory usage: #{ObjectSpace.memsize_of_all.to_s(:human_size)}"
    end
  end
end