title: MongoDB index converts to numberlong
body: <p>I'm trying to create a MongoDB index on a specific field with the following input:</p>
  
  <p>Collection: messages</p>
  
  <pre><code>source_id (integer)
  message_id (string)
  subject (string)
  timestamp (integer)
  </code></pre>
  
  <p>I'm in need to query this collection on the source and uid fields.</p>
  
  <p>Example document:</p>
  
  <pre><code>{ 
   "_id" : ObjectId("53aad315bffebc5d378b4569"), 
   "source_id" : NumberLong(1), 
   "message_id" : "AMA9D2TP9zWA.kuhlman.lowell@dietrich.com", 
   "subject" : "Labore aut est amet temporibus mollitia et.", 
   "timestamp" : NumberLong(1364645191) 
  }
  </code></pre>
  
  <p>A simple db.messages.getIndexes() returns that my message_id index is a NumberLong?</p>
  
  <pre><code>&gt; db.messages.getIndexes()
  [
  {
      "v" : 1,
      "name" : "_id_",
      "key" : {
          "_id" : 1
      },
      "ns" : "hs.messages"
  },
  {
      "v" : 1,
      "name" : "s_1",
      "key" : {
          "s" : NumberLong(1)
      },
      "ns" : "hs.messages"
  },
  {
      "v" : 1,
      "name" : "m_1",
      "key" : {
          "m" : NumberLong(1)
      },
      "ns" : "hs.messages"
  }
  ]
  </code></pre>