diff --git a/src/applications/differential/storage/DifferentialReviewer.php b/src/applications/differential/storage/DifferentialReviewer.php
index 836022c882..a0309beddd 100644
--- a/src/applications/differential/storage/DifferentialReviewer.php
+++ b/src/applications/differential/storage/DifferentialReviewer.php
@@ -23,6 +23,9 @@ final class DifferentialReviewer
           'columns' => array('revisionPHID', 'reviewerPHID'),
           'unique' => true,
         ),
+        'key_reviewer' => array(
+          'columns' => array('reviewerPHID', 'revisionPHID'),
+        ),
       ),
     ) + parent::getConfiguration();
   }