Here is the documentation on supported databases for 6.0: Supported Database Engines
We use PostgreSQL in our hosted environment and this is a good low cost alternative to Oracle. Hope that helps. We have no plans to support MySQL or Mongo for the analytics DB (and medium term we are looking at other analytics mechanisms that don't involve relational databases at all).
Thanks. Yeah it looks like PostgreSQL is our only option then and I knew it was the cheaper route. If we can use that then it eliminates the problems with having to use Oracle. I know with MySQL 5+ you can now do stored procedures so was hoping you would start to support it as well. Mongo is actually not a relational database so may want to look at that too. Thanks for the help!