title: Adding new property to each document in a large collection
body: <p>Using the mongodb shell, I'm trying to add a new property to each document in a large collection. The collection (Listing) has an existing property called Address. I'm simply trying to add a new property called LowerCaseAddress which can be used for searching so that I don't need to use a case-insensitive regex for address matching, which is slow.</p>
  
  <p>Here is the script I tried to use in the shell:</p>
  
  <pre><code>for( var c = db.Listing.find(); c.hasNext(); ) {
     var listing = c.next();
     db.Listing.update( { LowerCaseAddress: listing.Address.toLowerCase() });
  }
  </code></pre>
  
  <p>It ran for ~6 hours and then my PC crashed. Is there a better way to add a new property to each documentin a large collection (~4 million records)?</p>