Fast Rails API

Transcript

1. Fast Rails API

2. z

3. Max workload - 1500 rps Target response time - 100

   ms

4. rps 1500 65 What we have What we want

5. None

6. Rails 3 Ruby 1.9.3 Unicorn Nginx Postgresql Initial stack

7. # config/unicorn.rb worker_processes (ENV['UNICORN_WORKERS'] || 1).to_i # config/database.yml development: ...

   pool: 5 Connection pool https://devcenter.heroku.com/articles/concurrency-and-database-connections Unicorn worker Unicorn worker DB AR connection pool 1 connection per worker for max productivity

8. # config/unicorn.rb before_fork do |server, worker| if defined?(ActiveRecord::Base) ActiveRecord::Base.connection.disconnect! end

   end after_fork do |server, worker| if defined?(ActiveRecord::Base) config = Rails.application.config.database_configuration[Rails.env] config['reaping_frequency'] = ENV['DB_REAP_FREQ'] || 10 # seconds config['pool'] = ENV['DB_POOL'] || 5 ActiveRecord::Base.establish_connection(config) end end Establish DB connection after fork https://devcenter.heroku.com/articles/concurrency-and-database-connections

9. # config.ru if ENV['RAILS_ENV'] == 'production' require 'unicorn/worker_killer' max_request_min =

   500 max_request_max = 600 # Max requests per worker use Unicorn::WorkerKiller::MaxRequests, max_request_min, max_request_max oom_min = (240) * (1024**2) oom_max = (260) * (1024**2) # Max memory size (RSS) per worker use Unicorn::WorkerKiller::Oom, oom_min, oom_max end # Gemfile group :production do gem 'unicorn-worker-killer' end Unicorn worker killer

10. # Gemfile gem 'rails-api' # app/controllers/api/application_controller.rb class Api::ApplicationController < ActionController::API

    Rails-api

11. # config/application.rb require "active_record/railtie" require "action_mailer/railtie" require "action_controller/railtie" require "action_view/railtie"

    require "rails/test_unit/railtie" require "sprockets/railtie" Do not load ‘rails/all’

12. # config/application.rb require "active_record/railtie" require "action_mailer/railtie" require "action_controller/railtie" require "action_view/railtie"

    require "rails/test_unit/railtie" require "sprockets/railtie" Do not load ‘rails/all’

13. Connection pool Rails-api Do not load ‘rails/all’ Establish DB connection

    after fork/ new thread was created Unicorn worker killer Summary REALY HELPFUL HELPFUL IMPROVES STABILITY

14. rps 1500 66 What we have What we want

15. Postgresql tuning http://postgresql.leopard.in.ua/html/ http://momjian.us/main/writings/pgsql/hw_performance/ PG Backend PG Backend Shared Buffer

    Cache Write-Ahead Log Query and checkpoint operations Transaction durability Kernel Disk Buffer Cache fsync Disk Blocks

16. Postgresql tuning http://postgresql.leopard.in.ua/html/ http://momjian.us/main/writings/pgsql/hw_performance/ shared_buffers work_mem maintaince_work_mem checkpoint_segments effective_cache_size CLUSTER

    table

17. Rails 4 Ruby 2.1.0 Postgresql tuning Summary REALY HELPFUL

18. rps 1500 70 What we have What we want

19. Oj (JSON dumper) # Gemfile gem 'oj' json 0.810000 0.020000

    0.830000 ( 0.841307) yajl 0.760000 0.020000 0.780000 ( 0.809903) oj 0.640000 0.010000 0.650000 ( 0.666230) Good idea to use the fastest dumper

20. Active Model Serializers # Gemfile gem 'active_model_serializers' # app/serializers/user_serializer.rb class

    UserSerializer < ActiveModel::Serializer root false attributes :id, :guid, :current_channel_id, :current_telecast_ts, :created_at, :updated_at end # app/controllers/api/user_controller.rb def show @user = User.find params[:id] render json: @user end

21. Fragment caching https://devcenter.heroku.com/articles/caching-strategies http://signalvnoise.com/posts/3113-how-key-based-cache-expiration-works # app/controllers/api/application_controller.rb class Api::ApplicationController < ActionController::API

    include ActionController::Caching # app/controllers/api/users_controller.rb def show @user = User.find params[:id] json = cache ['v1', @user] do ActiveModel::Serializer.build_json(self, @user, {}).to_json end render json: json end

22. Fragment caching # app/controllers/api/users_controller.rb def index json = cache ['v1',

    CacheKeyRegistry.users] do @users = User.all ActiveModel::Serializer.build_json(self, @users, {}).to_json end render json: json end # lib/cache_key_registry.rb module CacheKeyRegistry class << self def users; key(User, __method__) end private def key(scope, key_prefix) count = scope.count max_updated_at = scope.maximum(:updated_at).try(:utc).try(:to_s, :number) "#{key_prefix}/all-#{count}-#{max_updated_at}" end end end “users/all-25-2014-02-23”

23. Fragment caching Active Model Serializers Oj (JSON dumper) Summary REALY

    HELPFUL HELPFUL

24. rps 1500 1500 What we have What we want

25. None

26. Rails 4 Ruby 2.1.0 Unicorn Nginx Postgresql Memcached Current stack

27. Do not instantiate AR objects Try OOBGC Try different web

    server (e.g. Puma) Other ideas

28. Do not instantiate AR objects def self.lightning connection.select_all(select([:guid, :current_channel_id, :current_telecast_ts]).arel).each

    do |attrs| attrs.each_key do |attr| attrs[attr] = type_cast_attribute(attr, attrs) end end end

29. A note about profiling tools

30. $ stackprof stackprof-cpu-6196-1393432908.dump --text ================================== Mode: cpu(1000) Samples: 545 (0.00%

    miss rate) GC: 48 (8.81%) ================================== TOTAL (pct) SAMPLES (pct) FRAME 42 (7.7%) 39 (7.2%) #<Module:0x000000020550f8>.escape 33 (6.1%) 23 (4.2%) ActiveRecord::ConnectionAdapters::Column.new_time 21 (3.9%) 21 (3.9%) Set#include? 13 (2.4%) 13 (2.4%) block in ActiveSupport::Dependencies#search_for_file 13 (2.4%) 13 (2.4%) block in ActiveSupport::Dependencies#autoloadable_module? 26 (4.8%) 4 (0.7%) Channel::Telecast#cover_url Stackprof

31. $ stackprof stackprof-cpu-6196-1393432908.dump --text --method 'Channel::Telecast#cover_url' Channel::Telecast#cover_url (/projects/undev/simpletv-backend/app/models/concerns/coverable.rb:12) samples: 4

    self (0.7%) / 26 total (4.8%) callers: 26 ( 100.0%) Channel::TelecastSerializer#cover callees (22 total): 22 ( 100.0%) Channel::Telecast#cover code: | 12 | def cover_url(version = nil) | 13 | if cover.file.nil? && external_cover 26 (4.8%) / 4 (0.7%) | 14 | external_cover.gsub(configus.cdn_host, '/cdn') Stackprof

32. https://github.com/MiniProfiler/rack-mini-profiler Rack Mini Profiler

33. Bullet Request log analyzer NewRelic Other

34. although Rails sucks without cache Don’t know what to do?

35. http://www.slideshare.net/maxlapshin/rails-26416461

36. Any other ideas? Questions? Anton Kalyaev twitter.com/AntonKalyaev github.com/akalyaev