Grant Tables Table Name user db Repl_client_priv Create_user_priv Create_tablespace_priv Create_role_priv Drop_role_priv Security columns ssl_type ssl_cipher x509_issuer x509_subject plugin authentication_string password_expired password_last_changed password_lifetime account_locked Password_reuse_history Password_reuse_time Password_require_current User_attributes Resource control columns max_questions max_updates max_connections max_user_connections The  user  table  plugin  and  authentication_string  columns store authentication plugin and credential information. The server uses the plugin named in the  plugin  column of an account row to authenticate connection attempts for the account. To assign a plugin to an account that is missing one, use the  ALTER USER  statement. The  plugin  column must be nonempty. At startup, and at runtime when  FLUSH PRIVILEGES  is executed, the server checks  user  table rows. For any row with an empty  plugin  column, the server writes a warning to the error log of this form: [Warning] User entry ’ user_name ’@’ host_name ’ has an empty plugin value. The user will be ignored and no one can login with this user anymore. The  password_expired  column permits DBAs to expire account passwords and require users to reset their password. The default  password_expired  value is  ’N’ , but can be set to  ’Y’  with the  ALTER USER  statement. After an account’s password has been expired, all operations performed by the account in subsequent connections to the server result in an error until the user issues an  ALTER USER  statement to establish a new account password. 1208