title: Server-Sent Events costs at server side
body: <p>If I understand the Server-Sent Events principle correctly, each time a client registers to an EventSource, it actually opens a new HTTP connection to the resource managing the event. Contrary to other HTTP requests, the connection stays alive so the server process/thread dedicated to this client keeps running until the client disconnects.</p>
  
  <p>What if we have 1000 clients connected to an application using SSE? Would we have 1000 processes/threads (doing the same thing) running concurrently just to handle the SSEs? I guess I'm wrong but if I'm not, is it really more efficient than the usual AJAX polling method where at least the server doesn't need to run that many processes/threads concurrently?</p>