Take a look at MonetDB, an open source column store database [1]. There was a commercialised extension to that called X100 targeting cache efficiency [2]. That

Take a look at MonetDB, an open source column store database [1]. There was a commercialised extension to that called X100 targeting cache efficiency [2]. That became VectorWise [3]. [1] http://www.monetdb.org http://www.monetdb.org [2] http://www.cidrdb.org/cidr2005/papers/P19.pdf http://www.cidrdb.org/cidr2005/papers/P19.pdf [3] http://en.wikipedia.org/wiki/Vectorwise http://en.wikipedia.org/wiki/Vectorwise