Matz on Ruby 2.0 at Heroku's Waza

Matz, the creator of Ruby, spoke at Waza for the 20th anniversary of the language and the release of Ruby 2.0. If you weren't in the sold out crowd, not to worry. Information should flow free and experiences should be shared; in line with those concepts you can watch Matz's talk right here, then read about what's new in this version of Ruby and how to run it on Heroku.

With slides available on speakerdeck

Keep reading for more information on Ruby 2.0 or check out our first batch of videos from Waza 2013. To stay up to date as we post new videos, follow us @heroku.


Iterating quickly means happier developers and happier customers. We optimize our platform to allow you to develop, stage, and deploy faster. Not only does this make running software easier, but it makes trying new technologies like Ruby 2.0 as simple as spinning up a new app. During Matz's talk at Waza, he mentioned that, while 1.9.3 is popular now, it took years after 1.8.7 was released to gain traction. With the release of Ruby 2.0 Matz hopes to reduce upgrading barriers and allow developers to iterate quicker using newer, faster and better tools.

Ruby 2.0 was written to be backwards compatible and it works with Rails 3.2.13 out of the box. If your Ruby apps are running using 1.8.7, you should upgrade. Ruby 1.8.7 is approaching End of Life (EOL) in three months on June 2013. EOL for Ruby 1.8.7 means no security or bug patches will be provided by the maintainers. Not upgrading means you're potentially opening up your application and your users to vulnerabilities. Don't wait till the final hour, upgrade now to be confident and secure.


Ruby 2.0 has a faster garbage collector and is Copy on Write friendly. Copy on Write or COW is an optimization that can reduce the memory footprint of a Ruby process when it is copied. Instead of allocating duplicate memory when a process is forked, COW allows multiple processes to share the same memory until one of the processes needs to modify a piece of information. Depending on the program, this optimization can dramatically reduce the amount of memory used to run multiple processes. Most Ruby programs are memory bound, so reducing your memory footprint with Ruby 2.0 may allow you to run more processes in fewer dynos.

If you’re not already running a concurrent backend consider trying the Unicorn web server.


In addition to running faster than 1.9.3, and having a smaller footprint, Ruby 2.0 has a number of new features added to the language including:

The list of new features is more than we can cover here. If you really wanted to dig in you can check the Ruby changelog

Running 2.0 on Heroku

If you’re interested in taking advantage of these new features give it a try on Heroku today. To run Ruby 2.0 on Heroku you'll need this line in your Gemfile:

ruby "2.0.0"

Then commit to git:

$ git add .
$ git commit -m "Using Ruby 2.0 in production"

We recommend that you test your app using 2.0 locally and deploy to a staging app before pushing to production. Now when you $ git push heroku master our Ruby buildpack will see that you've declared your Ruby version and make sure you get the right one.

20 years of simplicity, elegance, and programmer happiness

Heroku, since its founding, has been aligned with the key values of Ruby – simplicity, elegance, and programmer happiness. Heroku still believes in the power and flexibility of Ruby, and we've invested in the language by hiring Yukihiro "Matz" Matsumoto, Koichi Sasada and Nobuyoshi Nakada. We would like to thank them and the whole Ruby core team for making this release happen. Join us in celebrating Ruby's successes and in looking forward to the next twenty years by trying Ruby 2.0 on Heroku today.

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