MySQL8.0使用skip-grant-tables

# ./bin/mysqld --skip-grant-tables --user=mysql

mysql> update mysql.user set authentication_string=password('123456') where user='root';
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '('123456') where user='root'' at line 1

mysql> update mysql.user set authentication_string='' where user='root' and host='localhost';
mysql> flush privileges;

# mysql -uroot --socket=/tmp/mysql.sock
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 8.0.22-debug Source distribution
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> set password for 'root'@'localhost'='123456';
ERROR 1290 (HY000): The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement
mysql> flush privileges;
Query OK, 0 rows affected (0.13 sec)
mysql> set password for 'root'@'localhost'='123456';
Query OK, 0 rows affected (0.01 sec)

int mysql_execute_command(THD *thd, bool first_level) {
...
 /* Check if the statement fulfill the requirements on ACL CACHE */
  if (!command_satisfy_acl_cache_requirement(lex->sql_command)) {
    my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0), "--skip-grant-tables");
    goto error;
  }
...
}

bool skip_grant_tables(void) { return !initialized; }