diff --git a/lib/db/install.xml b/lib/db/install.xml
index fcc226d84d2..7c8e07d61e2 100644
--- a/lib/db/install.xml
+++ b/lib/db/install.xml
@@ -565,6 +565,7 @@
       <INDEXES>
         <INDEX NAME="useridto" UNIQUE="false" FIELDS="useridto"/>
         <INDEX NAME="useridfromto" UNIQUE="false" FIELDS="useridfrom, useridto"/>
+        <INDEX NAME="notificationtimeread" UNIQUE="false" FIELDS="notification, timeread"/>
       </INDEXES>
     </TABLE>
     <TABLE NAME="message_contacts" COMMENT="Maintains lists of relationships between users">
diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index 319524d3ac0..79fba742023 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -4455,5 +4455,20 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2015051101.07);
     }
 
+    if ($oldversion < 2015051102.03) {
+
+        // Define index notification (not unique) to be added to message_read.
+        $table = new xmldb_table('message_read');
+        $index = new xmldb_index('notificationtimeread', XMLDB_INDEX_NOTUNIQUE, array('notification', 'timeread'));
+
+        // Conditionally launch add index notification.
+        if (!$dbman->index_exists($table, $index)) {
+            $dbman->add_index($table, $index);
+        }
+
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2015051102.03);
+    }
+
     return true;
 }