title: MongoDB: How often should you open and close the database? Why?
body: <p>For every request I was opening the database, querying, closing the database. </p>
  
  <p>I was sporadically running into a <code>connection already opened</code> issue. </p>
  
  <p>I ended up changing the configuration  to just open mongo and keep it open. </p>
  
  <p>What are the downsides to this method?</p>
  
  <p>Thanks!</p>
  
  <p>(note: using node.js)</p>