title: Is there a way to skip over existing _id's for insert_many in Pymongo 3.0?
body: <p>I'm updating a DB that has several million documents with less than 10 _id collisions.</p>
  
  <p>I'm currently using the PyMongo module to do batch inserts using insert_many by:</p>
  
  <ol>
  <li>Querying the db to see if the _id exists </li>
  <li>Then adding the document to an array if _id doesn't exist</li>
  <li>Insert to the database using insert_many, 1000 documents at a time.</li>
  </ol>
  
  <p>There are only about 10 collisions out of several million documents and I'm currently querying the database for each _id. I think that I could cut down on overall insert time by a day or two if I could cut out the query process.</p>
  
  <p>Is there something similar to upsert perhaps that only inserts a document if it doesn't exist?</p>