Security Compatibility with MySQL

TiDB supports similar security functionality to MySQL 5.7, with the following exceptions:

Only the mysql_native_password password-based and certificate-based authentication is supported
External authentication (such as with LDAP) is not currently supported
Column level permissions are not supported
Password expiry, as well as password last-changed tracking and password lifetime are not supported #9709
The permission attributes max_questions, max_updated, max_connections, max_user_connections are not supported
Password validation is not currently supported #9741