-skip-lock-tables parameter instructs the mysqldump utility not to issue a LOCK TABLES command before obtaining the dump which will acquire a READ lock on every table. All tables in the database should be locked, for improved consistency in case of a backup procedure. Even with skip-lock-tables, while a table is dumped, will not receive any INSERTs or UPDATEs whatsoever, as it will be locked due the SELECT required to obtain all records from the table. It looks like this