title: Does Symfony3 / Doctrine open one MySQL connection per visitor?
body: <p>So I have developped this website with <code>Symfony3</code> and <code>Doctrine</code>. I have one major concern about performance with MySQL and more specifically the number of simultaneous open connexions.</p>
  
  <p>For the moment, one to five users are online on the website. What happens if, let's say, <code>1,500</code> users connect within one minute? Does Symfony3 or Doctrine handle this kind of situations? How can I be sure the website doesn't go down providing me with the <code>Too many connections</code> MySQL error?</p>
  
  <p>And if I go up to <code>5,000</code>? And <code>10,000</code>? The server has <code>4GB</code> of RAM and a <code>2.40Ghz</code> mono-core processor but I wouldn't worry about the hardware as I'm more concerned about MySQL.</p>
  
  <p>These situations already happened in the past but I was running the website with Wordpress and W3 Total Cache plugin. Should I consider using a cache manager such as <code>memcached</code> or else?</p>
  
  <p>In short, I'm concerned about the website becoming unavailable in case of sudden high trafic (and thought of the MysQL <code>Too many connections</code> error in first but I might be missing something even more important).</p>
  
  <p>Thanks for lightening me out on this one as I'm not fully aware about performance issues with Symfony.</p>