diff --git a/typo3/sysext/core/ext_tables.sql b/typo3/sysext/core/ext_tables.sql
index 2c902b5b81ef9a0637f73088a372096a6840ef44..8319c9b8f426447f7767a3f16981293db159c6fd 100644
--- a/typo3/sysext/core/ext_tables.sql
+++ b/typo3/sysext/core/ext_tables.sql
@@ -583,9 +583,9 @@ CREATE TABLE sys_refindex (
 	ref_string varchar(1024) DEFAULT '' NOT NULL,
 
 	PRIMARY KEY (hash),
-	KEY lookup_rec (tablename,recuid),
-	KEY lookup_uid (ref_table,ref_uid),
-	KEY lookup_string (ref_string)
+	KEY lookup_rec (tablename(240),recuid),
+	KEY lookup_uid (ref_table(240),ref_uid),
+	KEY lookup_string (ref_string(255))
 );
 
 #