diff --git a/mod/forum/db/install.xml b/mod/forum/db/install.xml
index 3f6b111012f..10867e81c8a 100644
--- a/mod/forum/db/install.xml
+++ b/mod/forum/db/install.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<XMLDB PATH="mod/forum/db" VERSION="20140605" COMMENT="XMLDB file for Moodle mod/forum"
+<XMLDB PATH="mod/forum/db" VERSION="20140815" COMMENT="XMLDB file for Moodle mod/forum"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:noNamespaceSchemaLocation="../../../lib/xmldb/xmldb.xsd"
 >
@@ -59,6 +59,7 @@
       </KEYS>
       <INDEXES>
         <INDEX NAME="userid" UNIQUE="false" FIELDS="userid"/>
+        <INDEX NAME="course" UNIQUE="false" FIELDS="course"/>
       </INDEXES>
     </TABLE>
     <TABLE NAME="forum_posts" COMMENT="All posts are stored in this table">
@@ -183,4 +184,4 @@
       </KEYS>
     </TABLE>
   </TABLES>
-</XMLDB>
+</XMLDB>
\ No newline at end of file
diff --git a/mod/forum/db/upgrade.php b/mod/forum/db/upgrade.php
index aaa335371cc..0aeee7f6fc2 100644
--- a/mod/forum/db/upgrade.php
+++ b/mod/forum/db/upgrade.php
@@ -185,5 +185,20 @@ function xmldb_forum_upgrade($oldversion) {
         upgrade_mod_savepoint(true, 2014051202, 'forum');
     }
 
+    if ($oldversion < 2014081500) {
+
+        // Define index course (not unique) to be added to forum_discussions.
+        $table = new xmldb_table('forum_discussions');
+        $index = new xmldb_index('course', XMLDB_INDEX_NOTUNIQUE, array('course'));
+
+        // Conditionally launch add index course.
+        if (!$dbman->index_exists($table, $index)) {
+            $dbman->add_index($table, $index);
+        }
+
+        // Forum savepoint reached.
+        upgrade_mod_savepoint(true, 2014081500, 'forum');
+    }
+
     return true;
 }
diff --git a/mod/forum/version.php b/mod/forum/version.php
index 0c36a5a527e..f6d07e00003 100644
--- a/mod/forum/version.php
+++ b/mod/forum/version.php
@@ -24,7 +24,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version   = 2014051202;       // The current module version (Date: YYYYMMDDXX)
+$plugin->version   = 2014081500;       // The current module version (Date: YYYYMMDDXX)
 $plugin->requires  = 2014050800;       // Requires this Moodle version
 $plugin->component = 'mod_forum';      // Full name of the plugin (used for diagnostics)
 $plugin->cron      = 60;