Is there a reason why OS X Mavericks Server is running Postgresql? I recently installed OS X Mavericks Server on my computer to use for Xcode continuous integration. I now see that the postgresql database is running via the Activity Monitor, and some investigation shows that it was started by Server.app, which is running Python, which started Postgres. I know that postgres is small and doesn't take up much resources, but I am just curious: Is there a reason why Server.app is running the database? I don't see a postgres service to turn on or off (which to be honest would be a great service to run via the server app).
From the OS X Server Advanced Administration manual, under the section on Postgres backups:


  The Server app on OS X Mavericks supports three separate database clusters:
  
  
  Calendar and Contacts
  Profile Manager
  Wiki and Xcode server