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Howdy Everyone!

This is being posted regularly to http://notelab.infogami.com/rubyonrailscamp2006

Feel free to add and edit! Formatting is in Markdown, but don't worry if you don't know it. Others will reformat as we go along.

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What is more valuable, Carbon or Silicon?

Max Dunn

Silcon (Servers) $10,000

Carbon (Programmers) $100,000

Productivity Increase 50%

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Efficient memcached Usage

Lessons learned while implementing memcached on zvents.com

Tyler Kovacs

Unasked question: stories about squid vs. memcache: some people opt for Squid over memcache because memcache is perceived not to be reliable

• Key point: don't tune memcache right away. You'll get a lot more by focusing on database tuning.

• Key point: But, don't let that stop you from planning ahead.

• memcached -vv

  • analagous to watching SQL statements in development log
• How often do you touch the cache per page request? You might be surprised.
• Facebook created a UDP interface to memcached to avoid TCP overhead

• How many hits can memcached handle?

  • Best case scenario: one key, one integer
  • 10k/sec on a $400 development box from Fry's (spec?)
  • Things will be slower in production
    • caching more complex data types (ActiveRecord objects) that have higher marshalling costs.
    • memcached run on separate hosts (network overhead)

• No support for stats in memcache client, use Cacti or similar to measure over time (RRDtool)

• memcache-client_extensions
  • get_multi
  • stats
  • flush_all
• extended_fragment_cache
  • in-process memory cache (FCGI, Mongrel process, what have you)
    • cuts touches to cache in half

• custom_benchmarks

  • allows you to log arbitrary information to the summary line in the Rails log

• Tip from Facebook: never cache something which came from the cache.

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last updated 2 years ago #