title: Why would a rails 5 upgrade drastically increase database CPU usage?
body: <p>I upgraded a production app from rails 4 to rails 5 a few days ago, and I have seen a big increase in CPU utilization on my RDS postgresql instance.  There does not seem to be any associated increase in database requests or decrease in speed.</p>
  
  <p>What could cause that?  What can I do to bring CPU utilization back down while still using Rails 5?</p>
  
  <p>The image below shows CPU utilization on the RDS instance.  The time of the upgrade is just to the left of the 11/09 line.</p>
  
  <p><a href="https://i.stack.imgur.com/EJtAE.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/EJtAE.png" alt="RDS Cpu utilization"></a></p>