13.7.1 Account Management Statements
MySQL account information is stored in the tables of the
mysql system database. This database and the access control system are discussed extensively in Chapter 5, MySQL Server Administration, which you should consult for additional details.
Some MySQL releases introduce changes to the grant tables to add new privileges or features. To make sure that you can take advantage of any new capabilities, update your grant tables to the current structure whenever you upgrade MySQL. See Section 2.11, “Upgrading MySQL”.
read_only system variable is enabled, account-management statements require the
SUPER privilege, in addition to any other required privileges. This is because they modify tables in the
mysql system database.