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Speed up Ruby-on-Rails with memcached

I wanted Memcached to speed up my CMS Typo, by allowing Ruby to take advantage of it for higher performance. Below are steps compiled from both sites, and used on my FreeBSD 6.0 server, but most of the steps should work as well in Linux. Read more for the steps.

First let’s get memcached installed

cd /usr/ports/databases/memcached/

We only want it to get past the configure step before we modify code

make configure

Now it’s time to modify the code (NOTE: the howto linked to above was specific to a FreeBSD issue, if using Linux you may not need to make this modification)

vi work/memcached-1.1.12/memcached.c

Find this line

#include "memcached.h"

Add the undef line below it and save

#include "memcached.h"

Now we want it to compile and install

make install

Once that’s complete, we want to enable memcached in rc.conf

echo "memcached_enable="YES"" >> /etc/rc.conf

Then start memcached

/usr/local/etc/rc.d/memcached.sh start

Next we’ll install the ruby-memcache client

cd ../ruby-memcache/
make install

Finally we’ll modify our Ruby-on-Rails app’s environment to use memcache as its session store (make a backup first!)

cp config/environment.rb config/environment.rb.dist
vi config/environment.rb

Find the line that tells session_store to use the database instead of the file system

#config.action_controller.session_store = :active_record_store

Modify it so it tells it to use memcached, and save

config.action_controller.session_store = :mem_cache_store

Stop Typo, and then manually clear the cache

rake sweep_cache

Now restart your Typo server, and you’re done! It should now be storing all session data via memcached instead of your database.