title: What is the relationship between three metrics of RDS: Free Memory,Active Memory and Freeable Memory?
body: <p>What are the three metrics of AWS RDS: Free Memory (Enhanced monitoring), Active Memory (Enhanced monitoring), and Freeable Memory (CloudWatch monitor)?</p>
  <p>What is the relationship between them?</p>
  <p>Look at these two pictures.</p>
  <p>The value of three metrics are different.</p>
  <p><img src="https://i.stack.imgur.com/nxXUC.png" alt="enter image description here" /></p>
  <p><img src="https://i.stack.imgur.com/3xBuF.png" alt="enter image description here" /></p>