MonetDB is a open-source database system for high-performance applications in data mining, OLAP, GIS, XML Query, text and multimedia retrieval. MonetDB often achieves a 10-fold raw speed improvement for SQL and XQuery over competitor RDBMSs.
MonetDB introduced innovations at all layers of a DBMS (see the MonetDB publications): a storage model based on vertical fragmentation, a modern CPU-tuned vectorized query execution architecture that often gives MonetDB a more than 10-fold raw speed advantage on the same algorithm over a typical interpreter-based RDBMS. MonetDB is one of the first database systems to focus its query optimization effort on exploiting CPU caches. MonetDB also features automatic and self-tuning indexes, run-time query optimization, a modular software architecture, etc.
Have a look at that recently published Google Talk about MonetDB / X11, an extremely fast column-store designed from scratch to get the best out of today’s hardware.