Mondrian is an OLAP query execution engine written in Java.
The company was acquired by Hitachi in 2015.
Relational
https://mondrian.pentaho.com/
https://github.com/pentaho/mondrian
https://mondrian.pentaho.com/documentation/
@MondrianOLAP
Pentaho
US
2002
Hitachi
Commercial, Open Source
Java
Eclipse Public License
https://en.wikipedia.org/wiki/Mondrian_OLAP_server