https://github.com/rails/rails/pull/36375

benchmark_save.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"
  gem "allocation_tracer"
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
end

class User < ActiveRecord::Base
end

ObjectSpace::AllocationTracer.setup(%i{path line type})

pp ObjectSpace::AllocationTracer.trace {
  1_000.times { User.create }
}.select { |k, _| k[2] == :T_ARRAY && k[0].end_with?("timestamp.rb") }

User.delete_all

Benchmark.ips do |x|
  x.report("User.create * 10") { User.transaction { 10.times { User.create } } }
end