The Thinkwise platform currently supports SQL Server, Oracle and DB2, three widely used RDBMS. According to Statista, they are indeed quite a popular choice and suited for large enterprise-level applications we make with Thinkwise.
PostgreSQL (Postgres) is a open source RDBMS unlike the others, that there are no license fees, is highly extensible, and is used over all the world, even by major companies.
I would love to see the interest by the Community for the Thinkwise platform to support PostgreSQL.