title: Mongodb/Mongoose bulkwrite(upsert) performance issues
body: <p>I am using mongoDB with mongoose for our Nodejs api where we need to do sort of seed for collections where data-source is a JSON, i am using <code>Model.bulkwrite</code> which internally uses mongodb's Bulkwrite(<a href="https://docs.mongodb.com/manual/core/bulk-write-operations" rel="nofollow noreferrer">https://docs.mongodb.com/manual/core/bulk-write-operations</a>).
  Code below,</p>
  <pre><code>await Model.bulkWrite(docs.map(doc =&gt; ({
      updateOne: {  ..... } // update document
      insertOne: { ....... } // insert document
      updateOne: {  ..... } // update document
      insertOne: { ....... } // insert document
      .
      .
      .n
  })))
  </code></pre>
  <p>This works fine for our current use-case with just few hundred documents,
  But we are worried about how will it scale,its performance when the number of documents will increase a lot, Like will there be any issues when number of document will be in 10 thousands.
  Just want to confirm that are we on the right path or is there any room for improvement.</p>