Scaling Rails Sites by default

Scaling Rails Site by default

2010年3月23日星期二

Scaling Rails Site : Reading Material #1- #5

http://blog.xdite.net/?cat=91

General Scaling




•Client-side Performance

•Database Performance

•Rails Performance


Client-side Performance


150ms > 5ms


YSlow!


Cookie Free Domain


main site http://www.example.org

static site http://asset.example.org


http://example.org

http://example.org

http://example-static.org


main site http://example.org

static site http://example-static.org


http://example.org

http://example.org



config.action_controller.asset_host =

“asset.example.org”


CDN


image_taghttp://asset.example.org/photos/small.jpg?1269316198


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


Parallel Download


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


Minimal HTTP Request


<%= 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






Cache-Control


def index

do_somthing expires_in 10.minutes

end

header[“Cache-Control”] = “max-age=600”


ETags


def show

@user = User.find(params[:id]) if stale?(:etag => @user) @content = @user.very_expensive_call respond_to do |format| formant.html.erb end endend

304 Not Modified


Last Modified


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


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 endend

304 Not Modified


Database Performance


ADD INDEXEXPLAIN every query, avoid table scan


SELECT ONLY NEEDuse “scrooge” plugin replace SELECT *


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


Use Counter Cachesize, count , length


Use CONSTANTCONSTANT will cache in memory


Use TransactionBEGIN COMMIT is expensive


Ruby / Rails Performance


Writing Efficiently Ruby Codehttp://ihower.tw/blog/archives/1691


http://ihower.tw/blog/archives/1691

http://ihower.tw/blog/archives/1691

Avoiding creating unnecessary object


Avoiding writing stupid code


str = “a” + “b” + “c”

==>

str = “#{a}#{b}#{c}”

str + other_str => new_str


tag_list = [“a”, “b”, “c”]

# rendering tags

tags = “”

tag_list.each do |t| tags +=”t” tags += “,”end

===>

tags = tag_list.join(“,”)

Array#join


tag_list = [“a”, “b”, “c”]

# rendering tags

tags = “”counter = 1

tag_list.each do |t| tags +=”counter” tags +=”t” tags += “,” counter +=1end

===>tag_list.each_with_index do |t , i|

Array#each_with_index


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


Knowing Rails API


render :partial is slowUse Fragment Caching


Rails action is expensiveUse Rails Metal


Ruby API is slowuse C extension


Conculsion


• Cache Everything

• Knowing API

• Drop in other language / system command

• Avoid hit DB

• Avoid hit Application


Thanks for listening


Scaling Rails Sites by default

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