Memcached by Brian Aker, Alan Kasindorf (dormando). Here are some quick, somewhat sparse notes. Follow the slides, it will help.
Memcached was actually created for LiveJournal. It has evolved a bit over time. Chaos to user based clustering, and then Brad implemented memcached. LiveJournal has about 30GB of cache available between 8-12 machines. The DB reads were down like 10x the moment they started using memcached (its much better now).
Its not only for simple objects (not just a single row)- you can use it for complex queries, and the result can be stored in memcached. Eins.de, Patrick Lenz, is also the freshmeat.net guy. He put memcached on the same machine as the MySQL database server (he has 32-bit machines, and MySQL can only use a certain amount of RAM, so the rest was …[Read more]