ERROR: Upgrade faifailed bin/mysqlcheck: Got error: 1045: Access denied for user 'root'@'localhost'

环境：

centos 6.5 

mysql 5.5.20 升级 5.6.25 报错：

mysql升级报错：

mysql.time_zone_transition_type                    OK
mysql.user                                         OK
Running 'mysql_fix_privilege_tables'...
Running 'mysqlcheck with default connection arguments
/usr/local/mysql/bin/mysqlcheck: Got error: 1045: Access denied for user 'root'@'localhost' (using password: NO) when trying to connect
FATAL ERROR: Upgrade failed

[root@t1 mysql-5.6.25]# /usr/local/mysql/bin/mysql_upgrade -uroot -p
Enter password: 
Looking for 'mysql' as: /usr/local/mysql/bin/mysql

拍错过程：

[root@t1 mysql-5.6.25]# /usr/local/mysql/bin/mysql_upgrade -uroot -p
Enter password: 
Looking for 'mysql' as: /usr/local/mysql/bin/mysql
Looking for 'mysqlcheck' as: /usr/local/mysql/bin/mysqlcheck
FATAL ERROR: Upgrade failed

[root@t1 mysql-5.6.25]# mysql -uroot -p
Enter password: 
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

[root@t1 mysql-5.6.25]# mysql -uroot -p123456
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

[root@t1 mysql-5.6.25]# mysql -uroot -p
Enter password: 
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

[root@t1 mysql-5.6.25]# ps -ef | grep mysqld

存在 3306

[root@t1 mysql-5.6.25]# mysql -uroot -p
Enter password: 
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

[root@t1 mysql-5.6.25]# find / -name mysql.sock
/var/lib/mysql/mysql.sock
/usr/local/mysql/mysql.sock

[root@t1 mysql-5.6.25]# ln -s /usr/local/mysql/mysql.sock /var/lib/mysql/mysql.sock 
ln: creating symbolic link `/var/lib/mysql/mysql.sock': File exists

[root@t1 mysql-5.6.25]# ll /var/lib/mysql/mysql.sock 
lrwxrwxrwx 1 root root 15 Mar  3 13:12 /var/lib/mysql/mysql.sock -> /tmp/mysql.sock

[root@t1 mysql-5.6.25]# rm /var/lib/mysql/mysql.sock 
rm: remove symbolic link `/var/lib/mysql/mysql.sock'? y

[root@t1 mysql-5.6.25]# mysql -uroot -p
Enter password: 
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

解决办法：

[root@t1 mysql-5.6.25]# ln -s /usr/local/mysql/mysql.sock /var/lib/mysql/mysql.sock 

[root@t1 mysql-5.6.25]# mysql -uroot -p
Enter password: 
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

说明密码错误。

赠送：

SELECT host FROM mysql.user WHERE User = 'root';

问题解决
[root@t1 mysql-5.6.25]# mysql -uroot -p123456
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 21
Server version: 5.6.25 Source distribution


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owners.


Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.


mysql> select @@version;
+-----------+
| @@version |
+-----------+
| 5.6.25    |
+-----------+
1 row in set (0.00 sec)


mysql> exit
Bye