diff --git a/lib/db/install.xml b/lib/db/install.xml
index e8c58bff708..d254ef52436 100644
--- a/lib/db/install.xml
+++ b/lib/db/install.xml
@@ -288,7 +288,8 @@
         <INDEX NAME="course-module-action" UNIQUE="false" FIELDS="course, module, action" NEXT="time"/>
         <INDEX NAME="time" UNIQUE="false" FIELDS="time" PREVIOUS="course-module-action" NEXT="action"/>
         <INDEX NAME="action" UNIQUE="false" FIELDS="action" PREVIOUS="time" NEXT="userid-course"/>
-        <INDEX NAME="userid-course" UNIQUE="false" FIELDS="userid, course" PREVIOUS="action"/>
+        <INDEX NAME="userid-course" UNIQUE="false" FIELDS="userid, course" PREVIOUS="action" NEXT="cmid"/>
+        <INDEX NAME="cmid" UNIQUE="false" FIELDS="cmid" PREVIOUS="userid-course"/>
       </INDEXES>
     </TABLE>
     <TABLE NAME="log_display" COMMENT="For a particular module/action, specifies a moodle table/field" PREVIOUS="log" NEXT="message">
diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index 30e1167a4d6..103282e659d 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -2857,6 +2857,23 @@ function xmldb_main_upgrade($oldversion=0) {
         upgrade_main_savepoint($result, 2007101508.04);
     }
 
+    if ($result && $oldversion < 2007101508.05) {
+
+    /// Define index cmid (not unique) to be added to log
+        $table = new XMLDBTable('log');
+        $index = new XMLDBIndex('cmid');
+        $index->setAttributes(XMLDB_INDEX_NOTUNIQUE, array('cmid'));
+
+    /// Launch add index cmid
+        if (!index_exists($table, $index)) {
+            $result = $result && add_index($table, $index);
+        }
+
+    /// Main savepoint reached
+        upgrade_main_savepoint($result, 2007101508.05);
+    }
+
+
     return $result;
 }
 
diff --git a/version.php b/version.php
index 79bdf90bccc..a768acc9df2 100644
--- a/version.php
+++ b/version.php
@@ -6,7 +6,7 @@
 // This is compared against the values stored in the database to determine
 // whether upgrades should be performed (see lib/db/*.php)
 
-    $version = 2007101508.04;  // YYYYMMDD   = date of the 1.9 branch (don't change)
+    $version = 2007101508.05;  // YYYYMMDD   = date of the 1.9 branch (don't change)
                             //         X  = release number 1.9.[0,1,2,3...]
                             //          Y = micro-increments between releases