mysql how to fix Access denied for user 'root'@'localhost'

原文地址：http://superuser.com/questions/603026/mysql-how-to-fix-access-denied-for-user-rootlocalhost

Follow steps below

1.Start the mysql server instance or daemon with the --skip-grant-tables option. (security setting)

$ mysqld --skip-grant-tables

2.Then Execute these statements.

$ mysql -u root mysql
$mysql> UPDATE user SET Password=PASSWORD('my_password') where USER='root';
$mysql> FLUSH PRIVILEGES;

3.Finally, restart the instance/daemon without the --skip-grant-tables option.

$ /etc/init.d/mysql restart

4.You should be able to connect with your new password.

$ mysql -u root -p

Enter password: my_password

NEW UPDATE

Mysql Unable to lock ibdata1 error fix

sudo mv /usr/local/mysql/data/ibdata1 /usr/local/mysql/data/ibdata1.bak
sudo mv /usr/local/mysql/data/ib_logfile0 /usr/local/mysql/data/ib_logfile0.bak
sudo mv /usr/local/mysql/data/ib_logfile1 /usr/local/mysql/data/ib_logfile1.bak
sudo cp -a /usr/local/mysql/data/ibdata1.bak /usr/local/mysql/data/ibdata1
sudo cp -a /usr/local/mysql/data/ib_logfile0.bak /usr/local/mysql/data/ib_logfile0
sudo cp -a /usr/local/mysql/data/ib_logfile1.bak /usr/local/mysql/data/ib_logfile1
sudo /etc/init.d/mysql restart