stack overflow - it's all about performance / marco cecconi (stack overflow)

Marco Cecconi@sklivvzhttp://sklivvz.com

ARCHITECTURE?

WHAT THE HECK IS

THAT?

In the past 12 months

• The Stack Exchange network grew from 130 to 150 sites (+15%)

• US site rank for visitors of the whole network improved from #44 to #19 (-25 ranks)

Tight, tight, code cycles

BATCAVE

Code-build-test cycle running on home machine

feature requests

BATCAVE DEV.SO

Test on the real servers

git push

BATCAVE DEV.SO

META.SE

1-click deploy

Users test on meta.stackexchange.com

(“baking”)

git push

BATCAVE DEV.SO

META.SE

1-click deploy

HALP!

git revert

git push

BATCAVE DEV.SO

NETWORK META.SE

1-click deploy

git push

1-clickdeploy

It’s live! Tons of users use it…

BATCAVE DEV.SO

NETWORK META.SE

1-click deploy

git push

1-clickdeploy

…and provide new

feature requests

Move fast and break things*

* Not the home page or question page :-)

Move fast and break things*

* Not the home page or question page :-)

“Normal” caching

Our frienemy:The Garbage Collector

Too many objects instantiated

Caching abuse

Compliler abuse

Framework abuse

Complex instance graph

Avoiding common patterns

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

Order order = orderRepository.Get(35);

Dependency injection pattern

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

A look at our source code

Automated TESTERS

What we do test:Open Source and Libraries

SECRET SAUCE

HIRE HACKERS…

…LET THEM CODE

BOSS MODE CODE

BOSS MODE TOOLS

• Performance is a feature• Always. Be. Shipping.• Use your circumstances.• Open source your libraries• 3 obscenely big monitors.

KEY TAKEAWAYS

Thank you

Marco Cecconi@sklivvz

http://sklivvz.com

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