Index: wp-includes/version.php
===================================================================
--- wp-includes/version.php	(revision 19798)
+++ wp-includes/version.php	(working copy)
@@ -11,7 +11,7 @@
  *
  * @global int $wp_db_version
  */
-$wp_db_version = 19798;
+$wp_db_version = 19799;
 
 /**
  * Holds the TinyMCE version
Index: wp-admin/includes/upgrade.php
===================================================================
--- wp-admin/includes/upgrade.php	(revision 19798)
+++ wp-admin/includes/upgrade.php	(working copy)
@@ -459,7 +459,7 @@
 	if ( $wp_current_db_version < 19389 )
 		upgrade_330();
 
-	if ( $wp_current_db_version < 19793 )
+	if ( $wp_current_db_version < 19799 )
 		upgrade_340();
 
 	maybe_disable_automattic_widgets();
@@ -1224,11 +1224,13 @@
 function upgrade_340() {
 	global $wp_current_db_version, $wpdb;
 
-	$wpdb->hide_errors();
-	$wpdb->query( "ALTER TABLE $wpdb->options DROP COLUMN blog_id" );
-	$wpdb->show_errors();
-}	
-	
+	if ( $wp_current_db_version < 19798 ) {
+		$wpdb->hide_errors();
+		$wpdb->query( "ALTER TABLE $wpdb->options DROP COLUMN blog_id" );
+		$wpdb->show_errors();
+	}
+}
+
 /**
  * Execute network level changes
  *
Index: wp-admin/includes/schema.php
===================================================================
--- wp-admin/includes/schema.php	(revision 19798)
+++ wp-admin/includes/schema.php	(working copy)
@@ -103,7 +103,6 @@
   comment_parent bigint(20) unsigned NOT NULL default '0',
   user_id bigint(20) unsigned NOT NULL default '0',
   PRIMARY KEY  (comment_ID),
-  KEY comment_approved (comment_approved),
   KEY comment_post_ID (comment_post_ID),
   KEY comment_approved_date_gmt (comment_approved,comment_date_gmt),
   KEY comment_date_gmt (comment_date_gmt),