MySQL 8.0 Release Notes
MySQL 8.0 Source Code Documentation
Pre-General Availability Draft: 2017-07-17
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MySQL account information is stored in the tables of the
mysql database. This database and the access
control system are discussed extensively in
Chapter 5, MySQL Server Administration, which you should consult
for additional details.
Important
Some MySQL releases introduce changes to the structure of 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 have the current structure whenever you upgrade MySQL. See Section 4.4.5, “mysql_upgrade — Check and Upgrade MySQL Tables”.
When the 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 database.