Benchmark

Benchmark.rb

require 'benchmark'

# rails runner  auto.rb


class AutoTest
  n = 1000

  Benchmark.bm do |x|

    x.report do
      n.times{ AutoSubmodel.except(:cities).all.last }
    end

    x.report do
      AutoSubmodel.all.last
    end

  end
end

module Mongoid
  module BaseModel
    extend ActiveSupport::Concern

    included do
      scope :recent, -> { desc(:create_at) }
    end

    module ClassMethods
      # https://github.com/rails/rails/blob/f37ad331089f64ab0386e8ac94b6626b45c38a1e/activesupport/lib/active_support/concern.rb

      def except(*attr)
        only(attribute_names.map(&:to_sym) - attr)
      end
    end

  end
end