title: Mongoose populate vs object nesting
body: <p>Is there any performance difference (process time of query) between using <a href="http://mongoosejs.com/docs/populate.html" rel="noreferrer">Mongoose population</a> and direct object inclusion ? When should each be used ?</p>
  
  <p>Mongoose population example:</p>
  
  <pre><code>var personSchema = Schema({
    _id     : Number,
    name    : String,
    stories : [{ type: Schema.Types.ObjectId, ref: 'Story' }]
  });
  
  var storySchema = Schema({
    _creator : { type: Number, ref: 'Person' },
    title    : String,
  });
  </code></pre>
  
  <p>Mongoose object nesting example:</p>
  
  <pre><code>var personSchema = Schema({
    _id     : Number,
    name    : String,
    stories : [storySchema]
  });
  
  var storySchema = Schema({
    _creator : personSchema,
    title    : String,
  });
  </code></pre>