Fetching type-safe entity with rom repo vs AR

gistfile1.txt

Calculating -------------------------------------
     type-safe users   273.000  i/100ms
      ar user models   257.000  i/100ms
-------------------------------------------------
     type-safe users      2.813k (± 1.7%) i/s -     14.196k
      ar user models      2.574k (±10.7%) i/s -     12.850k

Comparison:
     type-safe users:     2812.7 i/s
      ar user models:     2574.2 i/s - 1.09x slower

type_safe_entity_vs_ar.rb

require 'benchmark/ips'

require 'dry-data'
require 'dry/data/type/constrained'
require 'rom-sql'
require 'rom-repository'
require 'active_record'

DB_URL = 'postgresql://localhost/rom_repository'

ActiveRecord::Base.establish_connection(DB_URL)

class User < ActiveRecord::Base
end

rom = ROM.container(:sql, DB_URL) do |config|
  class Users < ROM::Relation[:sql]
  end

  config.register_relation(Users)
end

rom.gateways[:default].connection.execute('delete from users')

rom.relation(:users).insert(name: 'Jane')
rom.relation(:users).insert(name: 'Joe')
rom.relation(:users).insert(name: 'Jade')

module Types
end

Dry::Data.configure { |c| c.namespace = Types }
Dry::Data.finalize

module Types
  PrimaryKey = Strict::Int.constrained(gt: 0)
  Name = Strict::String.constrained(min_size: 3)
end

module Entities
  class User < Dry::Data::Struct
    attribute :id, Types::PrimaryKey
    attribute :name, Types::Name
  end
end

class UserRepo < ROM::Repository
  relations :users
end

user_repo = UserRepo.new(rom)

users = user_repo.users.as(Entities::User)

Benchmark.ips do |x|
  x.report('type-safe users') do
    users.to_a
  end

  x.report('ar user models') do
    User.all.to_a
  end

  x.compare!
end