1. Scaling Rails Site
by default

2. General Scaling
Scaling Rails Site :
Reading Material #1- #5
http://blog.xdite.net/?cat=91

3. •Client-side Performance
• Database Performance
• Rails Performance

4. Client-side Performance

5. 150ms > 5ms

6. YSlow!

7. Cookie Free Domain

8. main site http://www.example.org
static site http://asset.example.org

9. main site http://example.org
static site http://example-static.org

10. config.action_controller.asset_host =
“asset.example.org”

11. CDN

12. image_tag
http://asset.example.org/photos/small.jpg?1269316198

13. Parallel Download

14. config.action_controller.asset_host =
“asset%d.example.org”

15. Minimal HTTP Request

16. <%= javascript_include_tag :default, :cache => true %>
<%=stylesheet_link_tag “main”, :cache => true %>
http://asset.example.org/javascripts/all.js?1269316198
http://asset.example.org/stylesheets/all.css?1269316198

17. Cache-Control

18. def index
do_somthing
expires_in 10.minutes
end
header[“Cache-Control”] = “max-age=600”

19. ETags

21. def show
@user = User.find(params[:id])
if stale?(:etag => @user)
@content = @user.very_expensive_call
respond_to do |format|
formant.html.erb
end
end
end
304 Not Modified

22. Last Modified

23. [‘Last-Modfield’] [‘If-Modified-Since’] 304

24. def show
@user = User.find(params[:id])
if stale?(:last_modified => @user.updated_at )
@content = @user.very_expensive_call
respond_to do |format|
formant.html.erb
end
end
end
304 Not Modified

25. Database Performance

26. ADD INDEX
EXPLAIN every query, avoid table scan

27. SELECT ONLY NEED
use “scrooge” plugin replace SELECT *

28. Avoid N+1 Queries
use :include => [ “comment”]

29. Use Counter Cache
size, count , length

30. Use CONSTANT
CONSTANT will cache in memory

31. Use Transaction
BEGIN COMMIT is expensive

32. Ruby / Rails Performance

33. Writing Efficiently Ruby Code
http://ihower.tw/blog/archives/1691

34. Avoiding creating unnecessary object

35. Avoiding writing stupid code

36. str + other_str => new_str
str = “a” + “b” + “c”
==>
str = “#{a}#{b}#{c}”

37. Array#join
tag_list = [“a”, “b”, “c”]
# rendering tags
tags = “”
tag_list.each do |t|
tags +=”t”
tags += “,”
end
===>
tags = tag_list.join(“,”)

38. tag_list = [“a”, “b”, “c”] Array#each_with_index
# rendering tags
tags = “”
counter = 1
tag_list.each do |t|
tags +=”counter”
tags +=”t”
tags += “,”
counter +=1
end
===>
tag_list.each_with_index do |t , i|

39. Date.parse(“1992-02-13”)
very expensive, should use regexp

40. Knowing Rails API

41. render :partial is slow
Use Fragment Caching

42. Rails action is expensive
Use Rails Metal

43. Ruby API is slow
use C extension

44. Conculsion

45. • Cache Everything
• Knowing API
• Drop in other language / system command
• Avoid hit DB
• Avoid hit Application

46. Thanks for listening