The Architecture of Stack Overflow - Merge Lisbon 2014

Transcript

1. The  Architecture  Of   Marco Cecconi @sklivvz http://sklivvz.com

2. Sizing  up  the  problem  

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6. *source: Quantcast, Alexa #50-­‐ish  network  for  traffic*   (between imdb.com

   and t.co)

7. #50-­‐ish  network  for  traffic*   …and  #17  in  Portugal!?  

     *source: Quantcast, Alexa   much successful very traffic obrigado, yo!

8. 543,255,552  pageviews  in  the  last  30  days*   *source: Quantcast

9. Our  datacenter?  

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11. web servers load balancers redis search database http(s) http rest

    http protobuf sql sql protobuf tag engine
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13. We  are  sNll  scaling  up!  

14. Our  development  cycle  

15. BAT!CAVE Code-build-test cycle running on home machine feature requests

16. BAT!CAVE DEV.SO Test on the real servers git push

17. BAT!CAVE DEV.SO META.SE 1-click deploy Users test on meta.stackexchange.com (“baking”)

    git push

18. BAT!CAVE DEV.SO META.SE 1-click deploy HALP! git revert git push

19. BAT!CAVE DEV.SO NETWORK META.SE 1-click deploy git push 1-click deploy

    It’s live! Tons of users use it…

20. BAT!CAVE DEV.SO NETWORK META.SE 1-click deploy git push 1-click deploy

    …and provide new feature requests

21. Move  fast  and  break  things*   * Not the home

    page or question page :-)

22. Move  fast  and  break  things*   * Not the home

    page or question page :-)

23. Abusing  caching  

24. Network Level Caches (CDN, etc.) Server Level Cache (HttpRuntime.Cache) Site

    Level Cache (Redis) SQL Server Database Cache (384 gigs of RAM!) Solid State Disk
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28. RisoQo  &  SpagheS  

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34. Throwing away risotto… one grain at a time!

35. Abuse  caching  for  GC   performance  

36. IRepository<Order>  orderRepository  =            container.Resolve<IRepository<Order>>();  

      Order  order  =  orderRepository.Get(35); This is what you think you are doing…

37. …but if you think about it a bit more…

38. ...this is what you are actually doing! IRepository<Order>  repository  =

         new  ValidatingOrderRepository  (          new  SecurityRepository<Order>  (              new  LoggingRepository<Order>  (                  new  CachingRepository<Order>  (                      new  NHibernateRepository<Order>  ()                  )              )          )      );         Order  order  =  repository.Get(35);

39. Throwing away spaghetti… one strand at a time!

40. Dependency  InjecNon  is  our   version  of  spagheS  code  

41. Our  source  code  

42. Few projects :-)

43. Few projects :-) Few lines of code :-)

44. Few projects :-) Few lines of code :-) Eeek! very

    few tests :-S

45. Few projects :-) Few lines of code :-) Awesome community

    to help :-D Eeek! very few tests :-S

46. YAGNI*   * You Ain’t Gonna Need It!

47. Libraries  and  open  source  

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51. Wrap  code  in  libraries     and  open  source  it

     
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55. “SUPERHERO” CODING

56. HIRE “NINJA” CODERS

57. TOOLS LEVEL: “NINJA”

58. •     Performance  is  a  feature   •     Always.

     Be.  Shipping.   •     Use  your  circumstances.   •     Open  source  your  libraries   •     3  obscenely  big  monitors.     KEY TAKEAWAYS
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60. Marco Cecconi @sklivvz http://sklivvz.com we are hiring new ninjas from

    anywhere in the world!