title: AWS: Too many connections
body: <p>I have an <code>RDS instance</code> hosting a mySQL database. Instance size is <strong>db.t2.micro</strong></p>
  <p><a href="https://i.stack.imgur.com/zjoEO.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zjoEO.png" alt="enter image description here" /></a></p>
  <p>I also have an <code>ExpressJS</code> backend connecting to the mySQL <code>RDS instance</code> via a connection pool:</p>
  <p><a href="https://i.stack.imgur.com/QHqMW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QHqMW.png" alt="enter image description here" /></a></p>
  <p>Additionally i have a mobile app, the client, feeding off the <code>ExpressJS</code> API.</p>
  <p>The issue i'm facing is, either via the mobile app or via Postman, there are times where i get a '<strong>Too many connections</strong>' error and therefore several requests fail:</p>
  <p><a href="https://i.stack.imgur.com/0bFic.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0bFic.png" alt="enter image description here" /></a></p>
  <p>On the <code>RDS instance</code>. On current activity i sometimes get 65 connections, showing it's reaching the limit. What i need clarity on is:</p>
  <ol>
  <li>When 200 mobile app instances connect to the API, to the <code>RDS instance</code>, does it register as 200 connections or 1 connection from <code>ExpressJS</code>?</li>
  <li>Is it normal to be reaching the RDS instance 65 connection limit?</li>
  <li>Is this just a matter of me using <strong>db.t2.micro</strong> instance size which is not recommended for prod? Will upgrading the instance size resolve this issue?</li>
  <li>Is there something i'm doing wrong with my requests?</li>
  </ol>
  <p>Thank you and your feedback is appreciated.</p>