title: Which database fits with mark streams read/unread?
body: <p>I have a project that feed the line of streams into to page. After that each user open the stream, it marks the stream was read by that user. However user could mark unread to that stream. </p>
  
  <p>So there are a lot of streams and users to do this event. I find the database or solution to fit to this situation. I think the database should be high read/write throughput and keep the data in key-value.</p>
  
  <p>how the real-world do such as mail or group messenger.</p>