mysql常见问题
一，指定需要mysql.sock文件
[root@yz3110 mysql-5.5.24]# mysql -uroot -p
Enter password:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)
解决方法： mysql -uroot -p -S /var/lib/mysql/mysql.sock
或者
ln -s /var/lib/mysql/mysql.sock /tmp/mysql.sock
[root@yz3110 ~]# more /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock#指定mysql.sock的绝对路径
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
二，linux下mysql的root密码忘记解决方法
1．首先确认服务器出于安全的状态，也就是没有人能够任意地连接MySQL数据库。
因为在重新设置MySQL的root密码的期间，MySQL数据库完全出于没有密码保护的
状态下，其他的用户也可以任意地登录和修改MySQL的信息。可以采用将MySQL对
外的端口封闭，并且停止Apache以及所有的用户进程的方法实现服务器的准安全
状态。最安全的状态是到服务器的Console上面操作，并且拔掉网线。
2．修改MySQL的登录设置：
# vi /etc/my.cnf
在[mysqld]的段中加上一句：skip-grant-tables
例如：
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
skip-grant-tables
保存并且退出vi。
3．重新启动mysqld
# /etc/init.d/mysqld restart
Stopping MySQL: [ OK ]
Starting MySQL: [ OK ]
4．登录并修改MySQL的root密码
# /usr/bin/mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3 to server version: 3.23.56
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> USE mysql ;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> UPDATE user SET Password = password ( 'new-password' ) WHERE User = 'root' ;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 2 Changed: 0 Warnings: 0
mysql> flush privileges ;
Query OK, 0 rows affected (0.01 sec)
mysql> quit
Bye
5．将MySQL的登录设置修改回来
# vi /etc/my.cnf
将刚才在[mysqld]的段中加上的skip-grant-tables删除
保存并且退出vi。
6．重新启动mysqld
# /etc/init.d/mysqld restart
Stopping MySQL: [ OK ]
Starting MySQL: [ OK ]
mysql> grant all privileges on *.* to 'root'@'%' identified by '123qwe' with grant option;
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
