diff --git a/reference/mongo/mongocollection/aggregate.xml b/reference/mongo/mongocollection/aggregate.xml
index 6984dbcdfb..6cf4b7e227 100644
--- a/reference/mongo/mongocollection/aggregate.xml
+++ b/reference/mongo/mongocollection/aggregate.xml
@@ -62,7 +62,32 @@
  <refsect1 role="returnvalues">
   &reftitle.returnvalues;
   <para>
-   The result of the aggregation as an array.
+   The result of the aggregation as an array. The <varname>ok</varname> will
+   be set to <literal>1</literal> on success, <literal>0</literal> on failure.
+  </para>
+ </refsect1>
+
+ <refsect1 role="errors">
+  &reftitle.errors;
+  <para>
+   When an error occurs an array with the following keys will be returned:
+   <itemizedlist>
+    <listitem>
+     <simpara>
+      <varname>errmsg</varname> - containing the reason for the failure
+     </simpara>
+    </listitem>
+    <listitem>
+     <simpara>
+      <varname>code</varname> - the errorcode of the failure
+     </simpara>
+    </listitem>
+    <listitem>
+     <simpara>
+      <varname>ok</varname> - will be set to 0.
+     </simpara>
+    </listitem>
+   </itemizedlist>
   </para>
  </refsect1>
 
@@ -126,32 +151,37 @@ var_dump($results);
    <screen>
 <![CDATA[
 array(2) {
-  [0]=>
+  ["result"]=>
   array(2) {
-    ["_id"]=>
-    array(1) {
-      ["tags"]=>
-      string(4) "good"
+    [0]=>
+    array(2) {
+      ["_id"]=>
+      array(1) {
+        ["tags"]=>
+        string(4) "good"
+      }
+      ["authors"]=>
+      array(1) {
+        [0]=>
+        string(3) "bob"
+      }
     }
-    ["authors"]=>
-    array(1) {
-      [0]=>
-      string(3) "bob"
-    }
-  }
-  [1]=>
-  array(2) {
-    ["_id"]=>
-    array(1) {
-      ["tags"]=>
-      string(3) "fun"
-    }
-    ["authors"]=>
-    array(1) {
-      [0]=>
-      string(3) "bob"
+    [1]=>
+    array(2) {
+      ["_id"]=>
+      array(1) {
+        ["tags"]=>
+        string(3) "fun"
+      }
+      ["authors"]=>
+      array(1) {
+        [0]=>
+        string(3) "bob"
+      }
     }
   }
+  ["ok"]=>
+  float(1)
 }
 ]]>
    </screen>
@@ -191,29 +221,61 @@ var_dump($out);
    &example.outputs.similar;
    <screen>
 <![CDATA[
-array(7) {
-  [0]=>
-  array(2) {
-    ["_id"]=>
-    string(2) "TX"
-    ["totalPop"]=>
-    int(16986510)
-  }
-  [1]=>
-  array(2) {
-    ["_id"]=>
-    string(2) "PA"
-    ["totalPop"]=>
-    int(11881643)
-  }
-....
-  [6]=>
-  array(2) {
-    ["_id"]=>
-    string(2) "FL"
-    ["totalPop"]=>
-    int(12937926)
+array(2) {
+  ["result"]=>
+  array(7) {
+    [0]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "TX"
+      ["totalPop"]=>
+      int(16986510)
+    }
+    [1]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "PA"
+      ["totalPop"]=>
+      int(11881643)
+    }
+    [2]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "NY"
+      ["totalPop"]=>
+      int(17990455)
+    }
+    [3]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "IL"
+      ["totalPop"]=>
+      int(11430602)
+    }
+    [4]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "CA"
+      ["totalPop"]=>
+      int(29760021)
+    }
+    [5]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "OH"
+      ["totalPop"]=>
+      int(10847115)
+    }
+    [6]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "FL"
+      ["totalPop"]=>
+      int(12937926)
+    }
   }
+  ["ok"]=>
+  float(1)
 }
 ]]>
    </screen>
@@ -252,36 +314,90 @@ var_dump($out);
    &example.outputs.similar;
    <screen>
 <![CDATA[
-array(51) {
-  [0]=>
-  array(2) {
-    ["_id"]=>
-    string(2) "DC"
-    ["avgCityPop"]=>
-    float(303450)
-  }
-  [1]=>
-  array(2) {
-    ["_id"]=>
-    string(2) "DE"
-    ["avgCityPop"]=>
-    float(14481.913043478)
-  }
+array(2) {
+  ["result"]=>
+  array(51) {
+    [0]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "DC"
+      ["avgCityPop"]=>
+      float(303450)
+    }
+    [1]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "DE"
+      ["avgCityPop"]=>
+      float(14481.913043478)
+    }
+    [2]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "RI"
+      ["avgCityPop"]=>
+      float(18933.283018868)
+    }
+    [3]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "AL"
+      ["avgCityPop"]=>
+      float(7907.2152641879)
+    }
+    [4]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "NH"
+      ["avgCityPop"]=>
+      float(5232.320754717)
+    }
 ...
-  [49]=>
-  array(2) {
-    ["_id"]=>
-    string(2) "WI"
-    ["avgCityPop"]=>
-    float(7323.0074850299)
-  }
-  [50]=>
-  array(2) {
-    ["_id"]=>
-    string(2) "WV"
-    ["avgCityPop"]=>
-    float(2759.1953846154)
+    [45]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "WY"
+      ["avgCityPop"]=>
+      float(3359.9111111111)
+    }
+    [46]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "MN"
+      ["avgCityPop"]=>
+      float(5335.4865853659)
+    }
+    [47]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "OK"
+      ["avgCityPop"]=>
+      float(6155.7436399217)
+    }
+    [48]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "IL"
+      ["avgCityPop"]=>
+      float(9931.0182450043)
+    }
+    [49]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "WI"
+      ["avgCityPop"]=>
+      float(7323.0074850299)
+    }
+    [50]=>
+    array(2) {
+      ["_id"]=>
+      string(2) "WV"
+      ["avgCityPop"]=>
+      float(2759.1953846154)
+    }
   }
+  ["ok"]=>
+  float(1)
 }
 ]]>
    </screen>