oink , logger parser, memory

oink
Log parser to identify actions which significantly increase VM heap size

可以讓log 多出memory 的紀錄
Feb 08 11:39:54 ey33-s00302 rails[9076]: Memory usage: 316516 | PID: 9076

也可做report 來查 哪些request or action 耗 memory 比較多 $ oink --threshold=75 /tmp/logs/*<br /> ---- MEMORY THRESHOLD ----<br /> THRESHOLD: 75 MB<br /><br /> -- SUMMARY --<br /> Worst Requests:<br /> 1. Feb 02 16:26:06, 157524 KB, SportsController#show<br /> 2. Feb 02 20:11:54, 134972 KB, DashboardsController#show<br /> 3. Feb 02 19:06:13, 131912 KB, DashboardsController#show<br /> 4. Feb 02 08:07:46, 115448 KB, GroupsController#show<br /> 5. Feb 02 12:19:53, 112924 KB, GroupsController#show<br /> 6. Feb 02 13:03:00, 112064 KB, ColorSchemesController#show<br /> 7. Feb 02 13:01:59, 109148 KB, SessionsController#create<br /> 8. Feb 02 06:11:17, 108456 KB, PublicPagesController#join<br /> 9. Feb 02 08:43:06, 94468 KB, CommentsController#create<br /> 10. Feb 02 20:49:44, 82340 KB, DashboardsController#show<br /><br /> Worst Actions:<br /> 10, DashboardsController#show<br /> 9, GroupsController#show<br /> 5, PublicPagesController#show<br /> 5, UsersController#show<br /> 3, MediaController#show<br /> 2, SportsController#show<br /> 1, SessionsController#create<br /> 1, GroupInvitesController#by_email<br /> 1, MediaController#index<br /> 1, PostsController#show<br /> 1, PhotoVotesController#create<br /> 1, AlbumsController#index<br /> 1, SignupsController#new<br /> 1, ColorSchemesController#show<br /> 1, PublicPagesController#join<br /> 1, CommentsController#create<br />

benchmark

convenient benchmark

在 ~/.irbrc
<br />def benchmark<br /> cur = Time.now<br /> result = yield<br /> print "#{cur = Time.now - cur} seconds"<br /> puts " (#{(cur / $last_benchmark * 100).to_i - 100}% change)" rescue puts ""<br /> $last_benchmark = cur<br /> result<br />end<br />
就可以在consloe 輕鬆的做benchmark
>> benchmark{ User.find(2).records.wake.count}
0.00197 seconds (-1% change)

index , mysql slow qurey

A grand piano for your violin, 一篇關於哪些地方需要建index 的好文
table indexes in rails

找出 MySQL 哪些 Query 速度較慢
檢查 mysql sql 效能使用 MySQL Slow Queries
MySQL 常用指令筆記(問答)

Railscast skill (3)

Auto-Complete Association
<br /># product.rb<br />def category_name<br /> category.name if category<br />end<br /><br /># 注意可以用這樣生 association<br />def category_name=(name)<br /> self.category = Category.find_or_create_by_name(name) unless name.blank?<br />end<br /><br /># categories_controller.rb<br />def index<br /> @categories = Category.find(:all, :conditions => ['name LIKE ?', "%#{params[:search]}%"])<br />end<br />
<br /><!-- products/_form.html.erb --><br /><p><br /> <%= f.label :category_name %><br /> <%= text_field_with_auto_complete :product, :category_name, { :size => 15 }, { :url => formatted_categories_path(:js), :method => :get, :param_name => 'search' } %><br /></p><br /><br /><!-- categories/index.js.erb --><br /><%= auto_complete_result @categories, :name %><br />

Screencasts skill (II)

Dynamic Select Menus
可以用生個javascript stylesheets controller 來動態生js , css
在利用content_for 動態 include
<br /># application_helper.rb<br />def javascript(*files)<br /> content_for(:head) { javascript_include_tag(*files) }<br />end<br /><br />def stylesheet(*files)<br /> content_for(:head) { stylesheet_link_tag(*files) }<br />end<br />

Formatting Time
<br /># config/environment.rb<br />Time::DATE_FORMATS[:due_time] = "due on %B %d at %I:%M %p"<br />

Performing Calculations on Models
<br />Task.sum(:priority)<br />Task.sum(:priority, :conditions => 'complete=0')<br />Task.maximum(:priority)<br />Task.minimum(:priority)<br />Task.average(:priority)<br />p = Project.find(:first)<br />p.tasks.sum(:priority)<br />p.tasks.sum(:priority, :conditions => 'complete=0')<br />

Optimistic Locking
<br />rescue ActiveRecord::StaleObjectError<br /> @product.reload<br /> render :action => 'conflict'<br /><br /><br /><!-- _form.rhtml --><br /><%= f.hidden_field :lock_version %><br />

railscast skill

Refactoring User Name Part 2
<br /># models/user.rb<br />def full_name<br /> [first_name, middle_initial_with_period, last_name].compact.join(' ')<br />end<br /><br />def middle_initial_with_period<br /> "#{middle_initial}." unless middle_initial.blank?<br />end<br />

Fun with Find Conditions
Task.find(:all, :conditions => ["complete=? and priority=?", false, 3])<br />Task.find(:all, :conditions => ["complete=? and priority IS ?", false, nil])<br />Task.find(:all, :conditions => ["complete=? and priority IN (?)", false, [1,3]])<br />Task.find(:all, :conditions => ["complete=? and priority IN (?)", false, 1..3])<br /><br />Task.find(:all, :conditions => { :complete => false, :priority => 1 })<br />Task.find(:all, :conditions => { :complete => false, :priority => nil })<br />Task.find(:all, :conditions => { :complete => false, :priority => [1,3] })<br />Task.find(:all, :conditions => { :complete => false, :priority => 1..3 })<br /><br />Task.find_all_by_priority(1..3)<br />

Multibutton Form
<br /><!-- projects/new.rhtml --><br /><% if params[:preview_button] %><br /> <%= textilize @project.description %><br /><% end %><br />...<br /><%= submit_tag 'Create' %><br /><%= submit_tag 'Preview', :name => 'preview_button' %><br /><br /><br /><br /># projects_controller.rb<br />def create<br /> @project = Project.new(params[:project])<br /> if params[:preview_button] || !@project.save<br /> render :action => 'new'<br /> else<br /> flash[:notice] = "Successfully created project."<br /> redirect_to project_path(@project)<br /> end<br />end<br />

Refactoring Long Methods
<br /># models/cart.rb<br />def shipping_price<br /> if total_weight == 0<br /> 0.00<br /> elsif total_weight <= 3<br /> 8.00<br /> elsif total_weight <= 5<br /> 10.00<br /> else<br /> 12.00<br /> end<br />end<br /><br />def total_weight<br /> @total_weight ||= line_items.to_a.sum(&:weight)<br />end<br /><br /># models/line_item.rb<br />def weight<br /> for_download? ? 0 : product.weight<br />end<br />

Cleaning Up the View
<br /><br /><br /><!-- views/carts/show.rhtml --><br /><% title "Shopping Cart" %><br /><br /><table id="line_items"><br /> <tr><br /> <th>Product</th><br /> <th>Qty</th><br /> <th class="price">Unit Price</th><br /> <th class="price">Full Price</th><br /> </tr><br /> <%= render :partial => 'line_item', :collection => @cart.line_items %><br /> <tr><br /> <td class="total price" colspan="4"><br /> Total: <%= number_to_currency @cart.total_price %><br /> </td><br /> </tr><br /></table><br /><br /><!-- views/carts/_line_item.rhtml --><br /><[tr class="<%= cycle :odd, :even %>"]><br /> <td><%=h line_item.product.name %></td><br /> <td class="qty"><%= line_item.quantity %></td><br /> <td class="price"><%= free_when_zero(line_item.unit_price) %></td><br /> <td class="price"><%= free_when_zero(line_item.full_price) %></td><br /><[/tr]><br /><br /><br /><br /># models/line_item.rb<br />def full_price<br /> unit_price*quantity<br />end<br /><br /># models/cart.rb<br />def total_price<br /> line_items.to_a.sum(&:full_price)<br />end<br /><br /># helpers/carts_helper.rb<br />def free_when_zero(price)<br /> price.zero? ? "FREE" : number_to_currency(price)<br />end<br />

Create Model Through Text Field

Create Model Through Text Field
<br /># models/product.rb<br />belongs_to :category<br />attr_accessor :new_category_name<br />before_save :create_category_from_name<br /><br />def create_category_from_name<br /> create_category(:name => new_category_name) unless new_category_name.blank?<br />end<br /><br />#有一個create_category的 methods 可以create 相對應的user<br />