Performance on Rails

Ruby on Rails Performance Tips Barcamp Coimbra 2008 Pedro Sousa

Your application is slow

Caching in RoR

Before you begin You need to deﬁne where to place your cache (db, memory, ﬁle) You need to tweak you development environment to test caching

Setup up your environment > Rails 2.1 <= Rails 2.0

Types of Cache Store

Setup up your environment development.rb

3 Types of Caching Page Caching will always use File Store Action Caching & Fragment Caching Will use the cache store you deﬁned

Page Caching Transforms your views into pure HTML Best for pages with common content for all your users or very static pages

Example

Action Caching Works the same as way as page caching ... but goes through dispatcher to run ﬁlters and callbacks For example you can use it with pages that require authentication

Example

More options

Fragment Caching More ﬂexible Great for dynamic content directed at speciﬁc users or conditions (ex: your friends latest blog posts) Transforms portions of your views into rendered HTML

Examples of Caching

Example No caching

Fragment Caching

Oops, I forgot about the controller

the fragment

Cleaning up individual cache ﬁles

Cleaning up (brute force)

Cleaning up with memcached soon...

DB Model Cache It’s built into Rails, you don’t have to do nothing good for not making the same query twice limited... only works on the same request

DB Cache (stupid) example

Memcached New in Rails 2.0 Simple to use It’s like a Hash in memory, has a key/value way of working

Methods Rails.cache.read Rails.cache.write Rails.cache.fetch Rails.cache.delete Rails.cache.exist? Rails.cache.increment Rails.cache.decrement

example

example with data Model Controller

example with data View (ﬁrst time) View (second time, it’s read from the cache)

More info on caching http://www.railsenvy.com/2007/2/28/rails-caching- tutorial http://railscasts.com/episodes/115 http://www.thewebfellas.com/blog/2008/6/9/rails-2-1- now-with-better-integrated-caching http://www.akitaonrails.com/2008/5/25/rolling-with- rails-2-1-the-ﬁrst-full-tutorial-part-1

Tips for Optimization

Write Eﬁcient SQL Queries Bring only what you need

Eager Loading Sometimes it’s best to bring all data at once Prevents N+1 problem Optimized Eager Loading in Rails 2.1

Create indexes on DB It really makes a difference Don’t exagerate

Use Transactions Group Transactions when possible Minimizes errors Less effort on the Database

Reduce http requests Too many javascript and css ﬁles makes your page slow You can package all you ﬁles into only one

Solutions Built-in mechanism in Rails 2.0 but without js miniﬁcation Alternative plugin - Bundle-FU http://code.google.com/p/bundle-fu/

Bundling Example Before/After

Too many images? Use CSS Sprites Technique Less http requests More hard to manage

References about CSS Sprites http://css-tricks.com/css-sprites-what-they-are-why- theyre-cool-and-how-to-use-them/ http://www.alistapart.com/articles/sprites

Firebug & Yslow Track your page performance Easy to install and run Download from http://developer.yahoo.com/yslow/

Examples

More examples

TextMate Footnotes Useful plugin for Rails Download from http://github.com/drnic/rails-footnotes/ tree/master

Other Small Tips Use LibXML-Ruby for processing XML: http://libxml.rubyforge.org/ Log only what you need Use a CDN (ex: Amazon CloudFront) Patch the RUBY GC: http://rubyforge.org/projects/railsbench/

That’s it! Have fun! Don’t be afraid to experiment! Tweak until your satisfied! If all fails, invest in hardware. :)

The End

Thank you Pedro Sousa [blog] http://www.reinventar.com [work] http://www.thinkorange.pt [linkedin] http://www.linkedin.com/psousa

Performance on Rails

by Pedro Sousa on Sep 06, 2008

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Performance on Rails — Presentation Transcript