diff --git a/lib/db/install.xml b/lib/db/install.xml
index a35a832e9e7..51edcd67aba 100644
--- a/lib/db/install.xml
+++ b/lib/db/install.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<XMLDB PATH="lib/db" VERSION="20211001" COMMENT="XMLDB file for core Moodle tables"
+<XMLDB PATH="lib/db" VERSION="20211005" COMMENT="XMLDB file for core Moodle tables"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:noNamespaceSchemaLocation="../../lib/xmldb/xmldb.xsd"
 >
@@ -1918,6 +1918,7 @@
         <INDEX NAME="itemtype-needsupdate" UNIQUE="false" FIELDS="itemtype, needsupdate" COMMENT="used in grading cron"/>
         <INDEX NAME="gradetype" UNIQUE="false" FIELDS="gradetype" COMMENT="index for gradetype"/>
         <INDEX NAME="idnumber-courseid" UNIQUE="false" FIELDS="idnumber, courseid" COMMENT="non unique index (although programatically we are guarantying some sort of uniqueness both under this table and the course_modules one). TODO: We need a central store of module idnumbers in the future."/>
+        <INDEX NAME="itemtype-mod-inst-course" UNIQUE="false" FIELDS="itemtype, itemmodule, iteminstance, courseid" COMMENT="used in grading and course views"/>
       </INDEXES>
     </TABLE>
     <TABLE NAME="grade_grades" COMMENT="grade_grades  This table keeps individual grades for each user and each item, exactly as imported or submitted by modules. The rawgrademax/min and rawscaleid are stored here to record the values at the time the grade was stored, because teachers might change this for an activity! All the results are normalised/resampled for the final grade value.">
diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index 2d14a0ea5f6..43cbaa688f4 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -2921,5 +2921,20 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2021100600.03);
     }
 
+    if ($oldversion < 2021100600.04) {
+        // Define index itemtype-mod-inst-course (not unique) to be added to grade_items.
+        $table = new xmldb_table('grade_items');
+        $index = new xmldb_index('itemtype-mod-inst-course', XMLDB_INDEX_NOTUNIQUE,
+            ['itemtype', 'itemmodule', 'iteminstance', 'courseid']);
+
+        // Conditionally launch add index itemtype-mod-inst-course.
+        if (!$dbman->index_exists($table, $index)) {
+            $dbman->add_index($table, $index);
+        }
+
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2021100600.04);
+    }
+
     return true;
 }
diff --git a/version.php b/version.php
index 79617dfcc15..94c0299344f 100644
--- a/version.php
+++ b/version.php
@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2021100600.03;              // YYYYMMDD      = weekly release date of this DEV branch.
+$version  = 2021100600.04;              // YYYYMMDD      = weekly release date of this DEV branch.
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.
 $release  = '4.0dev+ (Build: 20211006)'; // Human-friendly version name