Mondrian OLAP server
Mondrian is an open source OLAP server, written in Java. It supports the MDX
query language, as well as the XML for Analysis and olap4j interface specifications. It reads from SQL and other data sources and aggregates data in a memory cache.
Mondrian is a relational OLAP.
History
The first public release of Mondrian was on August 9, 2002.It was acquired by Pentaho in 2005, and was integrated in Pentaho's Business intelligence software, with several major updates in 2007.