MonetDB is an open source column-oriented database management system developed at the Centrum Wiskunde & Informatica (CWI) in the Netherlands.It was designed to provide high performance on complex queries against large databases, such as combining tables with hundreds of columns and multi-million rows.MonetDB has been applied in high-performance applications for online analytical processing (OLAP), data mining, GIS, RDF, text retrieval and sequence alignment processing.