Our presentation on Israel Rails Conference 2012. Vitaly talking about rails performance, how to measure, what to improve and just as much important - what not to improve

1. Rails Performance
When, What and How
Vitaly Kushner
@vkushner

2. Vitaly Kushner
programming since middle 80s
professionally since early 90s
Rails since 2005
founded Astrails in 2008

3. http://astrails.com/blog

4. performance

5. slow
for whatever reason

6. performance

7. performance
• raw speed
• throughput
• scalability
• end-user

8. No time
to dive into details

9. When to optimize?
and when not to.

10. what to do with 1M
users

11. Celebrate!
you’ve made it.

12. why startups fail?

13. NOT because of
performance problems

14. 1 million users

15. first 1000 users!

16. have scalability
problem?

17. GREAT!
because it means you grow fast

18. later

19. Scalability Plan
• understand the limits
• know your next step

20. performance
does it matter?

21. YES!
performance is very important

22. Is 1% a lot?
yes, if you are Google.

23. Why not to optimize
anyway?

24. time and budget
usually limited

25. Measure
You can not improve what you do not measure.

26. Tools
• Yahoo Yslow
http://developer.yahoo.com/yslow/
• Google PageSpeed
https://developers.google.com/speed/pagespeed
• NewRelic - http://newrelic.com
• httperf & ab
• Blitz.io

27. limit number of records
from the database

28. oink
https://github.com/noahd1/oink

29. Instantiation Breakdown: Total: 14 |
User: 4 | Experience: 3 | Location: 3 |
Interest: 3 | Admin: 1

30. limit number of queries
prevent 1+N queries problem

31. bullet
https://github.com/flyerhzm/bullet

32. N+1 Query detected
Experience => [:interest]
Add to your finder: :include => [:interest]

33. define indexes
can be done later

34. query_reviewer
https://github.com/nesquena/query_reviewer

35. limit number of http
requests
consolidate assets
assets pipeline makes it easy

36. css at the top
js at the bottom
improves perceived page speed

37. low level hacks
• replace :include with :join
• explicit :select

38. not recommened

39. Maintainability
usually better then speed

40. low hanging fruits
• compress and http cache assets
• CDN libraries
• image sprites
• bundle images into CSS
• CDN for all static assets

41. Caching
much later

42. real performance
problem?

43. next time...

44. Thank you!
Slides and video will be published at
http://astrails.com/blog
Vitaly Kushner
@vkushner