My memcached talk at RailsConf 2007 (without notes). See the blog post: http://errtheblog.com/post/4872

1. CHRIS WANSTRATH
ERR FREE
[ http://errfree.com ]

12. 50,000,000 pages
no downtime

13. memcached.

14. Memcaching Rails
CHRIS WANSTRATH
ERR FREE
[ http://errfree.com ]

15. Memcaching Rails
CHRIS WANSTRATH
ERR FREE
[ http://errfree.com ]

16. chris wanstrath
railsconf 2007
kickin’ ass
with cache-fu

17. {}

18. class Memcache < Hash
undef :each, :keys
end

19. class Memcache < DRbHash
undef :each, :keys
end

20. $ memcached -vv
<3 server listening
<7 new client connection
<7 get app-test:Story:1
>7 END
<7 set app-test:Story:2 0
>7 STORED
<7 delete app-test:Story:1
>7 DELETED

21. $ memcached -vv
<3 server listening
<7 new client connection
<7 get app-test:Story:1
>7 END
<7 set app-test:Story:2 0
>7 STORED
<7 delete app-test:Story:1
>7 DELETED

25. YAGNI

26. UYRDNI

27. UYRDNI
(unless you really do need it)

29. class Presentation < ActiveRecord::Base
def self.get_cache(id)
if data = @cache.get(id)
data
else
data = find(id)
@cache.set(id, data)
data
end
end
end

30. class Presentation ActiveRecord::Base
def self.get_cache(id)
@cache.get(id) ||
@cache.set(id, find(id))
end
end

31. Fragments
Actions
Sessions
Objects

32. memcache-client

33. memcache-client
$ gem install memcache-client

34. topfunky memcached

35. CachedModel

36. Fragment Cache Store

37. Session Store

41. cache_fu

42. cache_fu
( acts_as_cached 2.0 )

43. Fragments
Actions
Sessions
Objects

44. acts_as_cached

45. config/memcached.yml
defaults:
ttl: 1800
namespace: railsconf
sessions: false
fragments: false
servers: localhost:11211

46. config/memcached.yml
defaults:
ttl: 1800
namespace: railsconf
sessions: true
fragments: true
servers: localhost:11211

47. config/memcached.yml
production:
benchmarking: false
sessions: true
fragments: true
servers:
- 192.185.254.121:11211
- 192.185.254.138:11211
- 192.185.254.160:11211

48. config/memcached.yml
production:
benchmarking: false
sessions: true
fragments: true
servers:
- 192.185.254.121:11211
- 192.185.254.138:11211
- 192.185.254.160:11211

49. class Presentation ActiveRecord::Base
acts_as_cached
end

50. get_cache
expire_cache

51. class Presentation ActiveRecord::Base
acts_as_cached
after_save :expire_cache
end

52. class Presentation ActiveRecord::Base
def self.get_cache(id)
if data = @cache.get(id)
data
else
data = find(id)
@cache.set(id, data)
data
end
end
end

53. class Presentation ActiveRecord::Base
def self.get_cache(id)
if not (data = @cache.get(id)).nil?
data
else
data = find(id)
@cache.set(id, data)
data
end
end
end

54. class Presentation ActiveRecord::Base
def self.get_cache(id)
if not (data = @cache.get(id)).nil?
data
else
data = find(id) || false
@cache.set(id, data)
data
end
end
end

55. Presentation.get_cache(1337)

58. class Presentation ActiveRecord::Base
acts_as_cached :conditions = 'published = 1'
end

59. class Presentation ActiveRecord::Base
acts_as_cached :finder = :find_live
end

60. Topic.find :all,
:conditions =
[quot;created_at ?quot;, 1.week.ago],
:order = 'post_count desc',
:limit = 5

62. class Topic ActiveRecord::Base
def self.weekly_popular(limit = 5)
find :all,
:conditions =
[quot;created_at ?quot;, 1.week.ago],
:order = 'post_count desc',
:limit = limit
end
end

63. Topic.weekly_popular

64. DB: 0.00 (0%)

65. class Topic ActiveRecord::Base
def self.cached_weekly_popular
get_cache(:weekly_popular) do
weekly_popular
end
end
end

66. Topic.cached_weekly_popular

68. ruby mocha

69. bdd test spec

70. A Ruby object acting as cached
- should be able to retrieve a cached version of itself
- should be able to set itself to the cache
- should pass its cached self into a block when supplied
- should be able to expire its cache
- should be able to reset its cache
- should be able to tell if it is cached
- should be able to set itself to the cache with an arbitrary ttl
Finished in 0.028509 seconds.
28 specifications (53 requirements), 0 failures

71. context quot;Calling #cached_weekly_popularquot; do
specify quot;should call #weekly_popular if not cachedquot; do
Topic.expects(:fetch_cache).returns(nil)
Topic.cached_weekly_popular.should.equal Topic.weekly_popular
end
specify quot;should return if cachedquot; do
Topic.expects(:get_cache).returns(true)
Topic.expects(:weekly_popular).never
Topic.cached_weekly_popular
end
end

72. Topic.cached(:weekly_popular)

74. def self.cache_key_with_date(id)
date = Date.today.to_s.tr(' ', '_')
cache_key_without_date(id) + ':' + date
end
class self
alias_method_chain :cache_key, :date
end

75. class Topic ActiveRecord::Base
def self.date_for_key
Date.today.to_s.tr(' ', '_')
end
def self.cached_weekly_popular
key = 'weekly_popular' + date_for_key
get_cache(key) { weekly_popular }
end
end

78. Topic.find(1, 2, 3)

79. Topic.get_cache(1, 2, 3)

80. user_ids = @topic.posts.map(:user_id).uniq
@users = User.get_cache(user_ids)

81. class ApplicationController
before_filter :local_cache_for_request
end

82. # pulls from memcache
@user = User.get_cache(1)
# pulls from local cache
@user = User.get_cache(1)

83. class ApplicationController
before_filter :set_cache_override
def set_cache_override
returning true do
ActsAsCached.skip_cache_gets =
!!params[:skip_cache]
end
end
end

84. www.mysite.com/home?skip_cache=1

88. reset_cache

89. @topic.set_cache

90. class Presentation ActiveRecord::Base
acts_as_cached
after_save :reset_cache
end

92. class Presentation ActiveRecord::Base
acts_as_cached :version = 1
end

94. monit

95. libketama

96. 1
600 200
400

97. 1
600 cache_get :railsconf 200
400

98. 1
:railsconf == 100
600 200
400

99. 1
:railsconf == 200
600 200
400

100. 1
:railsconf == 200
600 200

101. 1
700
:railsconf == 200
600 200
500 300
400

102. l33t h4x0rs
• Geoffrey Grosenbach
• Rob Sanheim
• Ryan King
• Lourens Naudé
• Michael Moen
• Corey Donohoe
• PJ Hyett
• Eric Hodel

103. {}
( thanks. any questions? )

104. http://flickr.com/photos/seibuone/144588686/
http://flickr.com/photos/j00zt1n/255430115/
http://flickr.com/photos/jameswong/145397570/
http://flickr.com/photos/xalpha/58368229/
http://flickr.com/photos/63503896@N00/35723413/
http://flickr.com/photos/mrcrash/145451993/
thanks
http://flickr.com/photos/psybernoid/398301743/
http://flickr.com/photos/45royale/422227291/
flickr
http://flickr.com/photos/andrson/420810541/
http://flickr.com/photos/joshuaweiland/370931770/
http://flickr.com/photos/zesmerelda/27258314/
http://flickr.com/photos/slice/390271923/
http://flickr.com/photos/cocoen/411960476/
http://flickr.com/photos/pinguino/198885132/
http://flickr.com/photos/davidfmiller/468476118/
http://laughingsquid.com - Scott Beale
http://flickr.com/photos/bail56/313536999/
http://flickr.com/photos/65995199@N00/272672183/