Blog

You had some unique business idea. You jot those down, thought about days after days, nights after nights! Then, you hired a talented bunch of developers, web designers, UX specialist. They built it using a great framework, say, Ruby on Rails, and you could see it in action that you were dreaming for months.

Your site is live now! Unfortunately, you do not have millions of dollars to spend on server (like Google or Facebook). You deployed it on a Linux box with limited memory. After a months of excitement, you realized that, users are encouraging enough in-terms of visit, but not enough to earn revenue. To make it worse, you found that, bounce rate is higher than anticipated. You ran some survey to find that users had some specific sets of expectations about responsiveness of the application, that your site couldn’t just meet. They wanted it to be quick, reliable, responsive — all your site isn’t.

Well, you didn’t consider this aspect when you assigned the project to the development team. What to do now?

This is where performance enhancement comes into place. To dig further, you need to start gathering data about performance of your system because people are quite bad at predicting which part of a computer program has the biggest performance problems. Once you find bottlenecks, you can solve your problem easily.

Here are some tips for you to measure and monitor performance in a Ruby on Rails application. Some tools and tips are equally applicable for other web applications.

1. Rails Performance Test – Benchmarking
Through Rails performance test, source of application’s memory or speed bottleneck and can be found. Benchmarking helps find out how fast each performance test runs. Each test case is run 4 times in benchmarking mode.

2. Rails Performance Test – Profiling
Profiling helps you to see the details of a performance test and provide an in-depth picture of the slow and memory hungry parts. Each test case is run 1 time in profiling mode.

3. Rails logger
The simplest way to get information about performance is to analyze rails log. It will provide you information of the time spent processing each request, broken down into rendering and SQL time. You can also find whether a particular part are cached or the occurrence of cache expiry.

4. Rails analyzer
The Rails Analyzer project contains a collection of tools (The Production Log Analyzer, The Action Profiler, Rails Analyzer Tools, The SQL Dependency Grapher) for Rails that let you discover biggest slow spots in your applications allowing you to best focus optimization efforts.

5. Rails footnote
It is a rails plugin which displays footnotes in your application for easy debugging, such as sessions, request parameters, cookies, filter chain, routes, queries, etc. Even more, it contains links to open files directly in your editor including your backtrace lines.

6. Query Reviewer
Query Reviewer is an advanced SQL query analyzer. It generates a page with explanation output of all SELECT queries, rate a page’s SQL usage, display interactive summary on page.

7. Slim Scrooge
SlimScrooge is an optimization layer to ensure your application only fetches the database content needed to minimize wire traffic, excessive SQL queries and reduce conversion overheads to native Ruby types.

SlimScrooge implements inline query optimization, automatically restricting the columns fetched based on what was used during previous passes through the same part of your code.

8. New Relic
New Relic is the all-in-one web application performance tool that lets you see performance from the end user experience down to the line of application code. It will also list the errors if such occurrence occur.

9. Rack-bug
It is a debugging toolbar for Rack applications implemented as middleware.

10. Firebug
Firebug is a firefox plugin and a very powerful tool. Thanks to Joe Hewitt for this life saver. Apart from many outstanding features, it helps to monitor network performance. You can see the load time of each files (when they started to load and when they are completed), filter it by type (e.g. javascript or CSS) and examining http headers.

That’s it! You can suggest more. These are a mere introduction. You can try those out and examine the health of your application. I have a plan to write another one with tips regarding enhancing performance based on the generated health report of a web application. Stay tuned for that!

In my previous article, I wrote about “10 ways and tools to measure performance of a rails application” . In this article I will give you 10 tips to boost up performance of you ruby on rails application. The boost up are in-terms of speed as well as quality. Enough happy talking, let’s dive into those.

1. Limit amount of data in a controller method

Thin controllers are easy to test and has a good performance profile because there’s some overhead involved in passing the controller instance variable around. In short, you need to follow “Thin controller and fat model”.

2. Split view in separate partials

In this way, views will be easier to read and easier to cache.

3. Choose right session storage

Based on your level of need, choose your session storage carefully. Here are what rails provide:

• CookieStore – Stores everything on the client.
• DRbStore – Stores the data on a DRb server.
• MemCacheStore – Stores the data in a memcache.
• ActiveRecordStore – Stores the data in a database using Active Record.

4. DRY (Don’t repeat yourself)

This is the most common things programmers tend to listen and don’t follow. Here is very basic example:

if(Player.find_by_id(1).name == "Tamim")
 return Player.find_by_id(1)
 else
 return nil
 end

It should be written by:

player = Player.find_by_id(1)
 if(player.name == "Tamim") then player else nil end

4. Eager loading

Eager loading is a way to solve the classic N + 1 query performance problem caused by inefficient use of child objects.

Let’s look at the following code. It will fetch zip of 10 users.

users = User.all(:limit => 10)
users.each do |user|
 puts user.address.zip
 end

Hence, 11 queries will be executed, 1 for the top and 10. The solution is to rewrite it to eager load address:

users = User.includes(:address).limit(10)

users.each do |user|
 puts user.address.zip
 end

You can use bullet, a great gem to kill N + 1 query problem.

5. Indexing

Database indexing is one of the simplest ways to improve database performance. The insert operation will become slower but will boost up fetching data which is more frequently used in web application.

6. Avoid dynamism

Although find_by and find_all_by dynamic methods are really cool, the are also kind of slow because each one needs to run through method_missing and parse the filename against the list of columns in database table.

7.  Caching

This is the purest way to speed up a rails application. Here are a short example of different types of caching:

• Page Caching
• Action Caching
• Fragment Caching:
•  SQL Caching
• Asset caching

8. Use of CDN

CDN aka content delivery network is an interconnected system of computers on the Internet that provides Web content rapidly to numerous users by duplicating the content on multiple servers and directing the content to users based on proximity.
When, concurrent users will come to your site, using CDN rather than serving asset (like image, javascript, stylesheets) from your server will boost up performance.

You can try CDN from Amazon Cloudfront or Rackspace cloud files

9. Image spriting

In websites, a significant times are consumed for loading large number of images. One way of minimizing is to sprite your images. This will reduce number of images to be served significantly.

10. Minify and GZip stylesheets and javascripts

This is the last point, but an important one. You can reduce size of the stylesheets and javascripts significantly by Minifying it and serve as GZip format. It will improve the performance significantly by reducing request/response time.

Well, these are pretty basic guidelines but surely help you to boost up your application. Now, the bounce rate of your site should be less and you are expected to be a happier product owner :-)

Feel free to enrich it by providing comments and feedback.