title: What NoSQL database to use as replacement for MySQL?
body: <p>When it comes to NoSQL, there are bewildering number of choices to select a specific NoSQL database as is clear in the <a href="http://en.wikipedia.org/wiki/NoSQL" rel="noreferrer">NoSQL</a> wiki.</p>
  
  <p>In my application I want to replace mysql with NOSQL alternative. In my application I have user table which has one to many relation with large number of other tables. Some of these tables are in turn related to yet other tables. Also I have a user connected to another user if they are friends. </p>
  
  <p>I do not have documents to store, so this eliminates document oriented NoSQL databases.
  I want very high performance.
  The NOSQL database should work very well with Play Framework and scala language.
  It should be open source and free.</p>
  
  <p>So given above, what NoSQL database I should use?</p>