Choose Database

By default OpManager comes with PG is along with the application. Database and application on the same server.

In matter of performance that's good right? But PG is the database that I can trust 100%? I say this because of large amount of information, the information supports the PG?

And now with regard to MSSQL, usually in the database is on a server and OpManager is another in a matter of performance, affect much the performance of OpManager?

What recommends using ManageEngine: PG or MSSQL?