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Google I/O notes: “Designing OpenSocial Apps for Speed and Scale”

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conference page

web dev best practices
– concat js and css files
– compress js and css
– quartermile api improvement after using yui compressor

latency
– use firebug for local testing
– measuring latency internationally
— use js: create img element w/ onload fn and report netwrok latency back
— do the same for data calls

image spriting
– use yslow to measure network requests

cahce-headers
– can be an apache config FilesMatch
– it looks like we can do this in php as well by just setting a header
– use a rand var in query string to bust cache

server-assisted optimizations
– for social networks, forcing performance tweaks results in network-level performance gain
– social networks usually have better infrastructure than app devs
– opensocial
— gadgets.io.getProxyUrl puts the url passed in on the cdn of the container
— content-rewrite feature in gadget spec controls which features are optimized
— use batch operations for network requests

opensocial best practices
– use OS 0.9 data pipelining and proxied content
– look on wiki.opensocial to learn more about data pipelining
– invalidation pattern
— invalidates cache for app associated w/ oauth key

database scaling
– joins are very expensive
– use master/slave architecture to scale horizontally
– use database partitioning to overcome replication costs
– bigtable already handles this
– use memcache to cache everything you can and filter db results in software-layer
– store frequently used data in a json blob

background processing
– as activities are generated, a note is made in a queue, on a seperate schdule, a bg process runs ops on the items in queue
– users see a slight delay (minutes)
– in app engine, use cron.yaml

quartermile’s (qm) data model
– enforce hard limits up front
– orkut limits friend lists to 1K, but myspace allows 100k +
– qm create artificial team concept and updates are limited to them
– app engine limits results to 1000 rows
– use cron to process and store expensive queries in the background
– store data in OS app data
— it’s all public, so don’t put secrets in here
— user-writable via js
— super fast
— perfect for storing pre-rendered bulk data
— in bg, render data, push it to app data. when app loads, retreive data from app data and store it in div!
– goals
— keep gadgets fast! we’re competing for a user’s attention
//use screencasts in presos

template-only profiles
– a way to declare the data an app needs w/o js
– produces fast profile rendering
– “process-on-server” OS feature
– all app’s on orkut profiles must use templates

summary
– invalidation, cache headers, bg processes, app data, limited profiles have benefits in multiple ways
– cahcing static content can reduce traffic by 90%

questions
//”office hours” supplement talk subjects

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Written by Erik

May 28, 2009 at 9:03 am

Posted in notes

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