title: slow MongoDB with an easy query
body: <p>I am a MongoDB starter and I have a small problem 
  a simple query like :</p>
  
  <pre><code>db.table.find ( { "text" : /a/ , "nb_ret" : { "$gt" : 2 } } )
  </code></pre>
  
  <p>took like 5min before giving the results</p>
  
  <p>In my database I have like 53 millions line</p>
  
  <p>And my server is :</p>
  
  <p><code>Intel Xeon E3 1225v2 , 4 c / 4 t , 3.2 GHz+ , ram : 32 Go , disk : 2x 2 To SATA</code> </p>
  
  <p>Is it normal ?</p>