Memcached Multi-Get vs Single Get

memcached-test.rb

# Gemfile
source "https://rubygems.org"

# Activate the gem you are reporting the issue against.
gem 'rails', '>= 7.0.4.3'
gem "dalli"
gem "rspec"
gem "rspec-its"
gem "rspec-rails"
gem "awesome_print"

# memcached.rb
#!/usr/bin/env ruby
# typed: false
# frozen_string_literal: true

require 'rubygems'
require 'rspec'
require 'rspec/its'
require 'action_controller/railtie'
require 'action_view/railtie'

ARRAY_SIZE = 10000

class TestApp < Rails::Application
  class << self
    attr_accessor :key_array, :array_size
  end
  
  self.array_size = ARRAY_SIZE
  self.key_array = []
  array_size.times.each { |index| self.key_array << index } 

  config.root = __dir__
  config.session_store :cookie_store, key: "cookie_store_key"
  config.hosts.clear
  #secrets.secret_key_base = "secret_key_base"

  config.logger = Logger.new($stdout)
  Rails.logger = config.logger

  routes.draw do
    get "/" => "test#index"
  end
end

class ApplicationController < ActionController::Base
  include Rails.application.routes.url_helpers
end

class TestController < ApplicationController
  def index
    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, ['127.0.0.1:11212'])

    write_time = Benchmark.measure do
      TestApp.key_array.each do |key|
        cache.fetch(key) { true } 
      end
    end

    missing_keys = []

    fetch_multi_time = Benchmark.measure do
      cache.fetch_multi(TestApp.key_array) do |key|
        missing_keys << key
      end
    end

    fetch_by_one_time = Benchmark.measure do
      TestApp.key_array.each do |key|
        cache.read(key) or warn("key #{key} is missing")
      end
    end

    render json: {
      array_size: TestApp.key_array.size,
      write_time: write_time.real,
      fetch_multi_time: fetch_multi_time.real,
      fetch_by_one_time: fetch_by_one_time.real,
      missing_keys: missing_keys.size
    }
  end
end

require "rspec/autorun"
require "rspec/rails"
require 'awesome_print'

RSpec.configure do |config|
  config.infer_spec_type_from_file_location!
end

RSpec.describe TestController, type: :request do
  describe "#index" do
    it 'should return json' do
      get '/'

      expect(response).to have_http_status(:ok)
      ap JSON.parse(response.body)
    end
  end
end

# Running:

$ bundle install
# Bundle complete! 6 Gemfile dependencies, 69 gems now installed.
# Use `bundle info [gemname]` to see where a bundled gem is installed.
$ bundle exec memcached.rb 2>/dev/null
I, [2023-11-08T12:01:03.145175 #66687]  INFO -- : Started GET "/" for 127.0.0.1 at 2023-11-08 12:01:03 -0800
D, [2023-11-08T12:01:03.171663 #66687] DEBUG -- : Dalli::Server#connect 127.0.0.1:11212
{
           "array_size" => 10000,
           "write_time" => 0.4958810000680387,
     "fetch_multi_time" => 0.006276000058278441,
    "fetch_by_one_time" => 0.4439320000819862,
         "missing_keys" => 0
}

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1 example, 0 failures