diff --git a/modules/comment/comment.class.php b/modules/comment/comment.class.php
index e51ab28ed..7300a3645 100644
--- a/modules/comment/comment.class.php
+++ b/modules/comment/comment.class.php
@@ -13,8 +13,19 @@
          * @brief implemented if additional tasks are required when installing
          **/
         function moduleInstall() {
+            $oDB = &DB::getInstance();
+
             // register the action forward (for using on the admin mode)
             $oModuleController = &getController('module');
+
+            $oDB->addIndex
+                (
+                    "comments",
+                    "idx_module_list_order",
+                    array("module_srl", "list_order"),
+                    true
+                );
+
             // 2007. 10. 17 add a trigger to delete comments together with posting deleted
             $oModuleController->insertTrigger('document.deleteDocument', 'comment', 'controller', 'triggerDeleteDocumentComments', 'after');
             // 2007. 10. 17 add a trigger to delete all of comments together with module deleted
@@ -44,6 +55,9 @@
             if(!$oDB->isColumnExists("comments", "blamed_count")) return true;
             if(!$oDB->isColumnExists("comment_voted_log", "point")) return true;
 
+            if (!$oDB->isIndexExists("comments", "idx_module_list_order"))
+                    return true;
+
             return false;
         }
 
@@ -80,6 +94,15 @@
             if(!$oDB->isColumnExists("comment_voted_log", "point"))
                 $oDB->addColumn('comment_voted_log', 'point', 'number', 11, 0, true); 
 
+            if (!$oDB->isIndexExists("comments", "idx_module_list_order"))
+                $oDB->addIndex
+                    (
+                        "comments",
+                        "idx_module_list_order",
+                        array("module_srl", "list_order"),
+                        true
+                    );
+
             return new Object(0, 'success_updated');
         }