title: MongoDB Query does not return Complete data after creating index
body: <p>I have a MongoDB Colllection which has following data</p>
  
  <pre><code>&gt; db.UpdateQueryRegistry.find({"studyId" : "20130117193010cfab"})
  
  {  "_id":ObjectId("50f95af799ac247d280484dc"),
     "attempts":0,
     "eTime": ISODate("2013-01-17T17:03:36.501Z"),
     "lastUpdDt": ISODate("2013-01-18T14:23:51.141Z"),
     "numQueries":1,
     "query":"Q1",
     "sTime":null,
     "start":0,
     "status":"COMPLETED",
     "studyId":"20130117193010cfab",
     "updateAction":"convertToIUorNO",
     "updateSource":"DOCUMENTSTATUS"
  }
  { "_id":ObjectId("50f95af799ac247d280484db"),
     "attempts":0,
     "eTime": ISODate("2013-01-17T19:50:34.392Z"),
     "lastUpdDt": ISODate("2013-01-18T14:23:51.141Z"),
     "numQueries":1,
     "query":"Q2",
     "sTime":null,
     "start":0,
     "status":"COMPLETED",
     "studyId":"20130117193010cfab",
     "updateAction":"instanceAddQuery",
     "updateSource":"ONTOLOGY"
  }
  { "_id":ObjectId("50f95af799ac247d280484da"),
     "studyId":"20130117193010cfab",
     "updateSource":"ONTOLOGY",
     "updateAction":"instanceDeleteQuery",
     "query":"Q3",
     "sTime":null,
     "eTime":null,
     "status":"PENDING",
     "numQueries":0,
     "lastUpdDt": ISODate("2013-01-18T14:23:51.141Z"),
     "attempts":0,
     "start":0
  }
  </code></pre>
  
  <p>The index is created on DB as follows:</p>
  
  <pre><code>&gt; db.UpdateQueryRegistry.stats().indexSizes
  
  {
      "_id_" : 8176,
      "studyId_1_status_1" : 24528,
      "studyId_1_updateSource_1_updateAction_1_query_1" : 98112
  }
  </code></pre>
  
  <p>But when I fire query </p>
  
  <pre><code>db.UpdateQueryRegistry.find({
      "studyId" : "20130117193010cfab",
      "updateSource" : "ONTOLOGY",
      "updateAction" : "instanceDeleteQuery"
  })
  </code></pre>
  
  <p>I do not get any results but when I fire query</p>
  
  <pre><code>db.UpdateQueryRegistry.find({
      "studyId" : "20130117193010cfab"
  })
  </code></pre>
  
  <p>I see 3 results displayed above. Please tell me if there is any error in this.</p>