![asynchronous personalization
[and CDNs and A/B testing and stuff]
Jon Pliske
Performance Engineering, Groupon
@jonpliske
jpliske@groupon.com](https://image.slidesharecdn.com/asynchronouspersonalizationandcdnsandab-110503190752-phpapp01/85/Asynchronous-Personalization-at-Groupon-JSConf-2011-1-320.jpg)
![[wait for applause]](https://image.slidesharecdn.com/asynchronouspersonalizationandcdnsandab-110503190752-phpapp01/85/Asynchronous-Personalization-at-Groupon-JSConf-2011-15-320.jpg)
Asynchronous Personalization at Groupon - JSConf 2011
- 1. asynchronous personalization [and CDNs and A/B testing and stuff] Jon Pliske Performance Engineering, Groupon @jonpliske jpliske@groupon.com
- 2. You might know me from this leaked photo on TechCrunch Jon Pliske Performance Engineering, Groupon @jonpliske jpliske@groupon.com
- 3. overview background CDN caching async personalization a/b/multivariate testing /w finch.js
- 4. performance anxiety big rails app performance issues big team === development process hurdles big traffic drinking problems Reaching limit of Rails' caching Low-level optimizations too "incremental" Rewriting SQL is boring Improve platform architecture
- 5. super bowl party prelude: jan 1. "btw we have pre/post super bowl commercials" jan 15. "scored an in-game spot, we good?" feb 15. offend the world "spike mode": CDN cache it all! disable login offload geocoding/subscriptions/orders to EC2 limited functionality === unhappy users
- 6. pics or it didn't happen
- 7. pics or it didn't happen
- 8. CDNs are neat pros cons low latency dynamic content "edge side nodes" personalization high capacity complexity static content overkill? specifically: personalized content (login menu, deals) analytics tracking a/b testing Rails developers
- 9. async personalization target: deal/division pages (> 50% of traffic) approach: 1. cache "anonymous" page in CDN 2. hide stuff 3. make AJAX request for personalized data/content 4. show stuff See Chris Williams' "Rails’ Best Caching Method is JavaScript" from GoRuCo 2010
- 13. "Anonymous" user before: initial page response time: 0.8 sec rendering time (e.g. loading css/js/images): 1 sec total: 1.8 sec after: initial page response time: 0.1 sec rendering time: 1 sec total: 1.1 sec only a little bit faster...(1.1 vs 1.8 sec) basically no server load => huge capacity increase!
- 14. Logged-in User / Subscriber before: initial page response time: 3 sec rendering time (e.g. loading js/css/images): 1 sec total time: 4 sec after: initial page response time: 0.1 sec rendering time (include AJAX call:1 sec): 1 sec total time: 1.1 sec Capacity constant: AJAX call still needs to hit Rails 300% faster!
- 16. development implications less Rails, more JS 1 user !== 1 (Rails) request goodbye: current_user session cookies testing
- 17. onCurrentUserReady(callback) callback when personalize API returns (or callback immediately for anonymous user) before: - if logged_in? do stuff for logged-in user - else do stuff for anonymous user after: Groupon.onCurrentUserReady(function(){ if (Groupon.currentUser.isAuthenticated) { do stuff for logged-in user } else { do stuff for anonymous user } });
- 18. analytics Problem: Request logging Solution: Tracking pixel (hit Nginx only, not Rails) Problem: Content changes Solution: Dynamic tracking pixel Problem: Tracking params (e.g. utm params, affiliate id, etc...) Solution: Store in cookie; append params to API request
- 19. a/b testing with Finch Problem: Finch uses view/controller logic to choose and track experiments and variants - experiment 'Two vs. Three Step Subscription' do |e| - e.variant 'Original' do %h1 Fill out this form to subscribe now - e.variant 'Two Step' do %h4 Follow these two steps to subscribe - e.variant 'Three Step' do %p Subscribe now - it only takes a few seconds
- 20. Finch.js Finch.Experiments.DelayedJSExperiment = { defer: function() { var experiment = this; FinchDemo.onCurrentUserReady(function() { experiment.deferedRun(this); }); }, before: function() { $('#delayed').hide(); }, after: function() { $('#delayed').show(); }, variants: { original: function() { $('#delayed .original').show(); }, alternate: function() { $('#delayed .alternate').show();}, } }; $(function() { Finch.run(window); });
- 21. Finch.js based on Google's "Overlapping Experiment Infrastructure" written in coffee-script open source soon-ishly ~ 15k of JS doesn't handle tracking/analytics/analysis side of testing (yet?)
- 22. the future pure-JSON API requests client-side rendering (/w mustache.js) HTML5 storage decouple from Rails development practices: front/back-end integration better testing better monitoring
- 23. Thank you! @jonpliske jpliske@groupon.com groupon.com/techjobs