That's Billion with a "B"

This article on scaling PostgreSQL to support Skype’s operations is well worth a read for anyone running a high-end PostgreSQL installation.

PostgreSQL is used “as the main DB for most of [Skype’s] business needs.” Their approach is to use a traditional stored procedure interface for accessing data and on top of that layer proxy servers which hash SQL requests to a set of database servers that actually carry out queries. The result is a horizontally partitioned system that they think will scale to handle 1 billion users.