Simple async demo stack with Rails 3 + EventMachine and Fibers.
- Hit localhost:3000/widgets to do a 1s async mysql query
- Hit localhost:3000/widgets/http to make an HTTP call back to /widgets - recursive! :-)
- Hit localhost:3000/twitter to load a mounted async Sinatra app (reports latests rails 3 tweets)
Howto / example commits:
- Configure ActiveRecord to use async mysql driver: Gemfile, and database.yml
- Use async HTTP fetching within Rails
- Mount async Sinatra app
Requirements:
- Ruby 1.9.x
- Async app server (thin)
- Rails 3
Environment setup:
- rvm install 1.9.2-preview3
- rvm gemset create async-rails
- rvm use 1.9.2-preview3@async-rails
- gem install rails --pre
- gem install thin
Starting up Rails:
- bundle install
- bundle exec thin -D start
ab -c 5 -n 10 http://127.0.0.1:3000/widgets/
Concurrency Level: 5
Time taken for tests: 2.740 seconds
Complete requests: 10
We're running on a single reactor, so above is proof that we can execute HTTP+MySQL queries in non-blocking fashion on a single run loop / within single process:
- AB opens 5 concurrent requests (10 total)
- Each request to /widgets/http opens an async HTTP request to /widgets - aka, we ourselves spawn another 5 requests
- Because the fiber pool is set to 10, it means we can process all 5 requests within ~1s (each mysql req takes 1s)
- 10 requests finish in ~2s
So, keep in mind that the size of 'database pool' is basically your concurrency throttle. In example above, we spawn 10 requests, which open another 10 internally, so in total we process 20 req's in ~2s on a single thing server. Just as expected.
Pushing the stack on my MBP (db pool = 250; fiber pool = 250; env = production; thin 1.2.7) results in:
Concurrency Level: 220
Time taken for tests: 10.698 seconds
Complete requests: 2000
Failed requests: 0
Write errors: 0
Total transferred: 470235 bytes
HTML transferred: 12006 bytes
Requests per second: 186.95 [#/sec] (mean)
Time per request: 1176.777 [ms] (mean)
Time per request: 5.349 [ms] (mean, across all concurrent requests)
Transfer rate: 42.93 [Kbytes/sec] received
For full AB trace see this gist
Resources: