The document discusses strategies for caching a Rails application to improve performance. It explains that caching stores information transparently so future requests are faster. It describes different types of caches like page, action, and fragment caches. Fragment caching is recommended, which caches parts of pages individually. The document also covers cache expiration, cache keys, and techniques like Russian doll caching to cache nested content. The goal of caching is to maximize the number of requests served from cache (cache hits) to improve response speed.

1. ESTRATÉGIASDE CACHE
PARA TUNAR SUA
APLICAÇÃO RAILS

2. CIRDES HENRIQUE
ENGENHEIRO DA COMPUTAÇÃO - UFPE
ORGANIZADOR DO ABRIL PRO RUBY
C0-FUNDADOR E DEV DO EVENTICK

4. 335 MIL TICKETS EMITIDOS
3600 ORGANIZADORES
1200 EVENTOS FUTUROS

5. RECIFE

6. RECIFE

7. O EVENTICK FICOU
FORA DO AR
POR 30 MINUTOS

8. ANTES DA SOLUÇÃO, UM PASSO ATRÁS:
MONITORAR A APLICAÇÃO
NewRelic
Nazar.io
HoneyBadger
Logentries
Inspectlet
The Informant

9. SOA?

10. SINGLE RAILS APP
LIKE SHOPIFY

11. 70% DAS REQUISIÇÕES
BATEM NA CACHE

12. O QUE É CACHE?

13. Cache é um componente que guarda
informações de forma TRANSPARENTE
para que futuras requisições
sejam mais RÁPIDAS

14. QUAL A
CARACTERÍSTICA
DA CACHE?

15. O QUE USA CACHE?

16. DO QUE É
CONSTITUÍDA
UMA CACHE?

17. CACHE = CASH

18. ARQUITETURA DE MEMÓRIA

19. CACHE HIT / CACHE MISS / CACHE RATIO

20. COMO MAXIMIZAR
O CACHE HIT?

21. BÉLÁDY’S ALGORITHM

22. RANDOM
REPLACEMENT
(RR)

23. LEAST-FREQUENTLY
USED
(LFU)

24. LEAST-RECENTLY
USED
(LRU)

25. O QUE É
WEBCACHING?

26. REQUISIÇÃO
Rails App
Reverse
Proxy
Browser
CDN Proxy

27. CACHE
SERVER-SIDE
CACHE
CLIENT-SIDE

28. PAGE
CACHE
ACTION
CACHE
FRAGMENT
CACHE
RAILS
CACHE

29. PAGE CACHE
WRITE ON DISK
BYPASS RAILS APPLICATION ENTIRE
STATELESS PAGES
NÃO FUNCIONA NO HEROKU

30. PAGE CACHE
class WeblogController < ActionController::Base
caches_page :show, :new
def update
expire_page action: 'show', id: params[:list][:id]
end
end

31. ACTION CACHE
SIMILAR TO PAGE CACHE
RUN FILTERS

32. ACTION CACHE
class PostsController < ActionController::Base
caches_action :show, expires_in: 1.hour
end

33. DEPRECATED

34. FRAGMENT CACHE
HTML CACHE AVAILABLE IN RAILS 4

35. RAILS CACHE
FRAGMENT AND ACTION CACHE BUILD ON RAILS.CACHE
CONFIG.ACTION_CONTROLLER.PERFORM_CACHING = TRUE

36. ActiveSupport::Cache::Store
FileStore
MemoryStore
NullStore
MemCacheStore

37. HOW TO USE IT
Rails.cache.write 'foo', 'bar'
Rails.cache.fetch 'foo'
Rails.cache.write :foo, {a: 'b'}

38. FRAGMENT CACHING
Rais.cache.fetch 'key',
expires_in: 5.minutes,
race_condition_ttl: 10.seconds do
#code
end

39. FRAGMENT CACHING
<% cache "event-#{event.id}" do %>
<%= render event %>
<% end %>

40. FRAGMENT CACHING
<% cache “event-#{event.id}”, expires_in: 1.year do %>
<%= render event %>
<% end %>

41. FRAGMENT CACHING
def update
expire_fragment("event-#{event.id}")
end

42. FRAGMENT CACHING
<% cache [:recent, event] do %>
<%= render event %>
<% end %>

43. FRAGMENT CACHING
ACTIVESUPPORT::CACHE.EXPAND_CACHE_KEY [:RECENT, EVENT]
=> "RECENT/EVENTS/12510-20141128131506743910000"

44. FRAGMENT CACHING
<% cache :recent_attendees, expires_in: 5.minutes do %>
<%= render partial: 'recent',
collection: Attendees.recent %>
<% end %>

45. FRAGMENT CACHING
<% cache(cache_key_for_attendees) do %>
<%= render partial: 'recent', collection:
Attendees.recent %>
<% end %>

46. FRAGMENT CACHING
module AttendeesHelper
def cache_key_for_attendees
count = Attendee.count
max_updated_at =
Attendee.maximum(:updated_at).try(:utc).try(:to_s, :number)
"attendees/all-#{count}-#{max_updated_at}"
end
end

47. FRAGMENT CACHING
<% cache(cache_key_for_attendees) do %>
<%= render partial: 'recent', collection:
Attendees.recent %>
<% end %>

48. PROBLEMA
COM TEMPLATE

49. CACHE Digests
<!-- app/views/events/show.html.erb -->
<% cache ["v1", @event] do%>
<h1>Team: <%= @event.title %></h1>
<%= render @event.attendees %>
<% end %>
<!-- app/views/attendees/_attendee.html.erb -->
<% cache ["v1", attendee] do %>
<span><%= attendee.name %></span>
<span><%= attendee.email %></span>
<% end %>

50. CACHE Digests

54. VIEWS/V1/ATTENDEES/1-20121220141922

59. VIEWS/V1/ATTENDEES/2-20121220141922

64. VIEWS/V1/EVENTS/2-20121220141922

66. CACHE Digests

70. VIEWS/ATTENDEES/1-20121220141922/74865FCB3E2752A0928FA4F89B3E4426

75. VIEWS/ATTENDEES/2-20121220141922/74865FCB3E2752A0928FA4F89B3E4426

80. VIEWS/EVENTS/2-20121220141922/4277F85C137009873C093088EF609E60

82. RUSSIAN
DOLL

83. Russian Doll

84. Russian Doll
% cache(cache_key_for_attendees) do %
All available attendees:
% Attendee.all.each do |a| %
% cache(a) do %
p%= a.name %/p
% end %
% end %
% end %

85. KNOWING IS
NOT ENOUGH
WE MUST APPLY

86. WILLING IS
NOT ENOUGH
WE MUST DO