From the webpage:
Open source analysis OLAP server written in Java. Enabling interactive analysis of very large datasets stored in SQL databases without writing SQL.
Welcome to the community home for Pentaho Analysis Services Community Edition also known as Mondrian. Mondrian is an Online Analytical Processing (OLAP) server that enables business users to analyze large quantities of data in real-time. Users explore business data by drilling into and cross-tabulating information with speed-of-thought response times to complex analytical queries.
Your topic map clients will have data in many formats. This is one tool for exploring their SQL datasets.