Is `definer` required when creating a stored procedure?

Question

I\'ve written all of MySQL procedures as root@localhost:

CREATE DEFINER=`root`@`localhost` PROCEDURE `p_add_user`(...)

Trouble is,

Answer 1

[EDIT: updated ref page]

You can specify execution privileges by adding the following statement in the procedure body (after declaration):

SQL SECURITY INVOKER

Example:

CREATE DEFINER=`root`@`localhost` PROCEDURE `p_add_user`()
SQL SECURITY INVOKER
(...)

Doing so, the actual invoker privileges are applied and the DEFINER part is omitted (even when it is auto-added during schema import). Full reference here: https://dev.mysql.com/doc/refman/5.7/en/stored-objects-security.html