诊断缓慢视图呈现的原因
我不知道什么时候开始，但是在我的应用程序中发生了一些不寻常的事情（在开发机器上本地运行）。 突然间我看到如下消息：
Started GET "/" for 127.0.0.1 at 2013-03-10 12:10:24 +1300 Processing by PagesController#home as HTML Rendered pages/home.html.erb within layouts/application (2.4ms) Completed 200 OK in 3242ms (Views: 3241.4ms | ActiveRecord: 0.0ms) 正如你可以看到3秒加载主页（一个相对简单的页面）…我们不是说硬重新加载..只需再次从另一个页面点击“家庭”链接。
不知道从哪里开始，但这是我的application.rb：
#config/boot.rb is loaded require File.expand_path('../boot', __FILE__) require 'rails/all' if defined?(Bundler) Bundler.require(*Rails.groups(:assets => %w(development test))) end module Goodsounds class Application < Rails::Application config.encoding = "utf-8" config.filter_parameters += [:password] config.assets.initialize_on_precompile = false config.assets.enabled = true config.action_controller.assets_dir = "#{File.dirname(File.dirname(__FILE__))}/public" config.assets.version = '1.0' config.autoload_paths += Dir["#{Rails.root}/lib/modules"] config.assets.paths += Dir["#{Rails.root}/app/assets/fonts/*"] config.assets.precompile += %w( .svg .eot .woff .ttf ) end end
…和dev.rb：
Goodsounds::Application.configure do # Settings specified here will take precedence over those in config/application.rb Paperclip.options[:command_path] = "/usr/bin/" config.action_mailer.default_url_options = { :host => 'localhost:3000' } config.action_mailer.raise_delivery_errors = true # set delivery method to :smtp, :sendmail or :test config.action_mailer.delivery_method = :smtp # these options are only needed if you choose smtp delivery config.action_mailer.smtp_settings = { :address => "localhost", :port => 1025 } # In the development environment your application's code is reloaded on # every request. This slows down response time but is perfect for development # since you don't have to restart the web server when you make code changes. config.cache_classes = false # Log error messages when you accidentally call methods on nil. config.whiny_nils = true # Show full error reports and disable caching config.consider_all_requests_local = true config.action_controller.perform_caching = false # Print deprecation notices to the Rails logger config.active_support.deprecation = :log # Only use best-standards-support built into browsers config.action_dispatch.best_standards_support = :builtin # Raise exception on mass assignment protection for Active Record models config.active_re cord.mass_assignment_sanitizer = :strict # Log the query plan for queries taking more than this (works # with SQLite, MySQL, and PostgreSQL) config.active_record.auto_explain_threshold_in_seconds = 0.5 # Do not compress assets config.assets.compress = false # Expands the lines which load the assets config.assets.debug = true end
编辑：
好的，这是我在新的文物上看到的。 虽然没有帮助我 有什么想法吗？
哦，我从Chrome时间线中学到了什么：
Send Request - Details Duration 0 (at 655 ms) Resource localhost Request Method GET Receive Response - Details Duration 0.043 ms (at 4.17 s) Resource localhost Status Code 200 MIME Type text/html Receive Data - Details Duration 176.329 ms (at 4.17 s) Self Time 7.037 ms CPU Time 176.329 ms Aggregated Time 061.194 ms114.664 ms0.471 ms0 Resource localhost Encoded Data Length 303 Bytes Used Heap Size 29.1 MB (+5.7 MB) Finish Loading - Details Duration 0 (at 4.35 s) Resource localhost
顺便说一下，我禁用了quiet_assetsgem，看看我能在terminal发现..再..没有帮助：
Started GET "/" for 127.0.0.1 at 2013-03-10 21:46:40 +1300 Processing by PagesController#home as HTML Rendered pages/home.html.erb within layouts/application (43.4ms) Completed 200 OK in 3501ms (Views: 3480.9ms | ActiveRecord: 19.4ms) Started GET "/assets/dataTables/jquery.dataTables.bootstrap.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /dataTables/jquery.dataTables.bootstrap.css - 304 Not Modified (11ms) Started GET "/assets/chosen.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /chosen.css - 304 Not Modified (5ms) Started GET "/assets/select2.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /select2.css - 304 Not Modified (4ms) Started GET "/assets/autocomplete.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /autocomplete.css - 304 Not Modified (1ms) Started GET "/assets/branches.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /branches.css - 304 Not Modified (2ms) Started GET "/assets/bubbles.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bubbles.css - 304 Not Modified (1ms) Started GET "/assets/business_show.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /business_show.css - 304 Not Modified (1ms) Started GET "/assets/chunkyfive_font.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /chunkyfive_font.css - 304 Not Modified (1ms) Started GET "/assets/consumer_show.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /consumer_show.css - 304 Not Modified (2ms) Started GET "/assets/datatable_styling.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /datatable_styling.css - 304 Not Modified (1ms) Started GET "/assets/datepicker.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /datepicker.css - 304 Not Modified (2ms) Started GET "/assets/devise_links.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /devise_links.css - 304 Not Modified (1ms) Started GET "/assets/dispenser_show.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /dispenser_show.css - 304 Not Modified (1ms) Started GET "/assets/fonts.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /fonts.css - 304 Not Modified (1ms) Started GET "/assets/forms.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /forms.css - 304 Not Modified (2ms) Started GET "/assets/gmaps4rails.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /gmaps4rails.css - 304 Not Modified (1ms) Started GET "/assets/jquery-ui-1.10.0.custom.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /jquery-ui-1.10.0.custom.css - 304 Not Modified (2ms) Started GET "/assets/jumbotrons.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /jumbotrons.css - 304 Not Modified (1ms) Started GET "/assets/layout.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /layout.css - 304 Not Modified (1ms) Started GET "/assets/open_sans.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /open_sans.css - 304 Not Modified (2ms) Started GET "/assets/popover.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /popover.css - 304 Not Modified (1ms) Started GET "/assets/reviews.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /reviews.css - 304 Not Modified (1ms) Started GET "/assets/spinner.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /spinner.css - 304 Not Modified (2ms) Started GET "/assets/style_show.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /style_show.css - 304 Not Modified (2ms) Started GET "/assets/style_show_reviews.css?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /style_show_reviews.css - 304 Not Modified (2ms) Started GET "/assets/jquery.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /jquery.js - 304 Not Modified (3ms) Started GET "/assets/jquery_ujs.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /jquery_ujs.js - 304 Not Modified (3ms) Started GET "/assets/ui.custom.min.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /ui.custom.min.js - 304 Not Modified (1ms) Started GET "/assets/bootstrap-transition.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-transition.js - 304 Not Modified (5ms) Started GET "/assets/bootstrap-affix.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-affix.js - 304 Not Modified (3ms) Started GET "/assets/bootstrap-alert.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-alert.js - 304 Not Modified (4ms) Started GET "/assets/bootstrap-button.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-button.js - 304 Not Modified (5ms) Started GET "/assets/bootstrap-carousel.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-carousel.js - 304 Not Modified (3ms) Started GET "/assets/bootstrap-collapse.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-collapse.js - 304 Not Modified (3ms) Started GET "/assets/bootstrap-dropdown.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-dropdown.js - 304 Not Modified (3ms) Started GET "/assets/bootstrap-modal.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-modal.js - 304 Not Modified (3ms) Started GET "/assets/bootstrap-scrollspy.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-scrollspy.js - 304 Not Modified (3ms) Started GET "/assets/bootstrap-tab.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-tab.js - 304 Not Modified (3ms) Started GET "/assets/bootstrap-tooltip.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-tooltip.js - 304 Not Modified (5ms) Started GET "/assets/bootstrap-popover.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-popover.js - 304 Not Modified (52ms) Started GET "/assets/bootstrap-typeahead.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap-typeahead.js - 304 Not Modified (3ms) Started GET "/assets/bootstrap.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /bootstrap.js - 304 Not Modified (13ms) Started GET "/assets/gmaps4rails/gmaps4rails.base.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /gmaps4rails/gmaps4rails.base.js - 304 Not Modified (1ms) Started GET "/assets/gmaps4rails/gmaps4rails.bing.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /gmaps4rails/gmaps4rails.bing.js - 304 Not Modified (2ms) Started GET "/assets/gmaps4rails/gmaps4rails.googlemaps.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /gmaps4rails/gmaps4rails.googlemaps.js - 304 Not Modified (2ms) Started GET "/assets/gmaps4rails/gmaps4rails.mapquest.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /gmaps4rails/gmaps4rails.mapquest.js - 304 Not Modified (2ms) Started GET "/assets/gmaps4rails/gmaps4rails.openlayers.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /gmaps4rails/gmaps4rails.openlayers.js - 304 Not Modified (2ms) Started GET "/assets/jqueryplugins/addresspicker.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /jqueryplugins/addresspicker.js - 304 Not Modified (2ms) Started GET "/assets/jqueryplugins/browser_detect.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /jqueryplugins/browser_detect.js - 304 Not Modified (3ms) Started GET "/assets/jqueryplugins/charts.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /jqueryplugins/charts.js - 304 Not Modified (2ms) Started GET "/assets/jqueryplugins/jquery.alphanumeric.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /jqueryplugins/jquery.alphanumeric.js - 304 Not Modified (1ms) Started GET "/assets/jqueryplugins/jquery.formrestrict.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /jqueryplugins/jquery.formrestrict.js - 304 Not Modified (2ms) Started GET "/assets/jqueryplugins/jquery.lazyload.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /jqueryplugins/jquery.lazyload.js - 304 Not Modified (1ms) Started GET "/assets/jqueryplugins/raty.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /jqueryplugins/raty.js - 304 Not Modified (2ms) Started GET "/assets/dataTables/jquery.dataTables.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /dataTables/jquery.dataTables.js - 304 Not Modified (13ms) Started GET "/assets/dataTables/jquery.dataTables.bootstrap.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /dataTables/jquery.dataTables.bootstrap.js - 304 Not Modified (63ms) Started GET "/assets/lib/abstract-chosen.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /lib/abstract-chosen.js - 304 Not Modified (12ms) Started GET "/assets/lib/select-parser.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /lib/select-parser.js - 304 Not Modified (12ms) Started GET "/assets/chosen.jquery.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /chosen.jquery.js - 304 Not Modified (8ms) Started GET "/assets/chosen-jquery.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /chosen-jquery.js - 304 Not Modified (9ms) Started GET "/assets/select2.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /select2.js - 304 Not Modified (7ms) Started GET "/assets/highcharts.js?body=1" for 127.0.0.1 at 2013-03-10 21:46:44 +1300 Served asset /highcharts.js - 304 Not Modified (1ms)
顺便说一句，按照reddit我的预编译资产和运行服务器的build议。 看到梦幻般的速度：
Processing by PagesController#home as HTML Rendered pages/home.html.erb within layouts/application (1.1ms) Completed 200 OK in 6ms (Views: 5.4ms | ActiveRecord: 0.0ms)
好吧，不知道这是否提供任何帮助，但在堆栈中的这两行代码之间发生重大延迟：
From: /home/funkdified/.rvm/gems/ruby-1.9.3-p392@goodsounds/gems/actionpack-3.2.13.rc1/lib/action_controller/metal/implicit_render.rb @ line 5 ActionController::ImplicitRender#send_action: 3: def send_action(method, *args) 4: ret = super => 5: default_render unless response_body 6: ret 7: end [2] pry(#<PagesController>)> next
主要延迟
From: /home/funkdified/.rvm/gems/ruby-1.9.3-p392@goodsounds/gems/actionpack-3.2.13.rc1/lib/action_controller/metal/implicit_render.rb @ line 6 ActionController::ImplicitRender#send_action: 3: def send_action(method, *args) 4: ret = super 5: default_render unless response_body => 6: ret 7: end
好的，我知道了（最后）。 没有改变我的实际资产，我现在看到这是发展：
Started GET "/" for 127.0.0.1 at 2013-03-11 23:14:33 +1300 Processing by PagesController#home as HTML Rendered pages/home.html.erb within layouts/application (1.3ms)
原来这个延迟是由于development.rb中的config.assets.debug = true造成的。 将其设置为false可以解决问题。
Rails核心团队的辩论看起来像默认closures这个 ，但决定反对这个想法。 在将来，我很乐意看到他们在development.rb的注释部分放置一些东西，以避免潜在的重大延迟。
我可以build议如下：
# Expands the lines which load the assets # May cause significant delays in view rendering
太棒了，他们听到我在嘀咕和更新导轨 ！
在rails 4.1+中，我也遇到了同样的问题。 亚伯兰的答案只是部分完成。
你可以离开config.assets.debug = true但应该禁用新的资产validationfunction
# Adds additional error checking when serving assets at runtime. # Checks for improperly declared sprockets dependencies. # Raises helpful error messages. config.assets.raise_runtime_errors = false
禁用config.assets.debug解决scheme仅适用于编译资产一次，资产validation一次。 资产validation是大部分时间花费的地方。
如果你从rails 3.2.13来的话，注意到一堆人遇到了这个问题，回到3.2.12似乎解决了这个问题。 你可以在这里find更多的信息在github上 。
在我的情况下禁用config.assets.debug sped事情了一点，但恢复到3.2.12下降请求时间从大约4秒到250ms左右。
看看NewRelic.com – 它的成本，但免费试用将允许你完全剖析你的应用程序，并找出瓶颈的地方。
除了New Relic，通过一般检查，例如什么时候开始？ 你最近变了什么？ 你升级了Rails和/或任何gem？ 查看并从源代码pipe理中运行一些以前的版本，并尝试明确哪个提交导致问题。
所有浏览器都发生问题吗？ 尝试启动Chrome浏览器时间线查看器，您将能够看到浏览器是否陷入了一段特定的JavaScript。
另外尝试切换您的本地开发Web服务器到瘦，这个问题是否持续？
祝你好运！
你在OSX上通过.local服务吗？
如果是的话，会把我在我的评论中发现的post作为解决scheme：
子域约束（Rails 3）使本地服务器（瘦）很慢
