title: How to kill dead cursors in MongoDB
body: <p>When querying a MongoDB collection, if the read will take a while, the cursor times out.
  There's a <code>timeout=False</code> option, which makes the cursor not time out, and then it must be closed manually.</p>
  
  <p>When a script crashes with an open cursor, that cursor presumably just stays alive in the DB until the next restart.
  In the MMS monitoring dashboard, these are visible as a high constant in the "cursors" chart.</p>
  
  <p><img src="https://i.stack.imgur.com/Q39OY.png" alt="mms cursors"></p>
  
  <p>What are the consequences of this?
  And how can I kill these cursors manually?</p>