Here is the process we went through to get our tests passing after upgrading our Rails app from Rails 4.1 to Rails 4.2.0.beta2. We updated the rails gem version and ran bundle update, and found these gems needed to be upgraded to resolve dependencies: gem 'rspec-rails', '~> 2.14.1' upgraded to '~> 3.1.0' gem 'rspec', '~> 2.14.1' upgraded to '~> 3.1.0' gem 'sass-rails', '>= 3.2' upgraded to '>= 5.0.0.beta1' gem 'bootstrap-sass', '~> 3. ... Read more

Again, two months, almost to the day since we last hit problems with deployment, we are here again. Up till the day before, deployments worked fine if a little slow, but now they fail with a timeout. The site is running okay but remains at that version: The process is now faultless: “Deploying Versions with Zero Downtime”. Here is what we did: STEP 1) Take a DB snapshot. STEP 2) Duplicate the environment in AWS management console, using the DB snapshot just created. ... Read more

…with less sql queriesA Rails application will make a large number of sql queries per page unless steps are taken to mitigate this. This is bad because it degrades the performance of your app, affects your ability to scale, and will cost you money. Install the New Relic gem to see the sql queries made when loading a page in your app. Here is what we changed to reduce the number of sql queries per page: ... Read more

When we first designed the database schema for our Rails project, we employed the ‘Single Table Inheritance’ and ‘Polymorphic Associations’ strategies to two different and deserving cases. For the latter case, we needed to model different types of a class having common properties as well as unique. So for this, Polymorphic Association was chosen over Single Table Inheritance to achieve a cleaner data structure ( with less holes ). Since then, the project has evolved and undergone several performance enhancement iterations, and today we decided it was time to lose the polymorphic association at the center of an n + 1 performance problem. ... Read more

Two months, almost to the day since we last hit problems with deployment, it looks like we are here again. Up till the day before, deployments worked fine if a little slow, but now they fail with a timeout. The site is running okay but remains at that version: It is not possible to retrieve the logs - also due to an execution timeout. It is possible to SSH to the EC2 server but looking around the logs it appears everything is rolled back. ... Read more