grant all on databasename.tablename to 'username'@'xxx.xxx.xxx.xxx' identified by 'complexpassword';

这是基本授权的基本格式，“all”那个位置可以分得更细，“databasename.tablename”这个地方可以使用通配符“*”，“@”后面的地址部分可以使用通配符“%”来限定网段，比如：

grant SELECT,INSERT, UPDATE, DELETE, CREATE, DROP, ALTER on *.* to 'myuser'@'%' identified by 'mypasswd';

grant all on discuz.* to 'username'@'xxx.xxx.xxx.%' identified by 'complexpassword';

grant all on discuz.* to 'username'@'%' identified by 'complexpassword';

flush privileges;//刷新生效

show processlist;//显示哪些线程正在运行

show variables like "max_connections";//显示最大连接数

以下是使用通配符“%”查变量：

mysql> show variables like "%connect%";

+--------------------------+-------------------+

| Variable_name            | Value             |

+--------------------------+-------------------+

| character_set_connection | latin1            |

| collation_connection     | latin1_swedish_ci |

| connect_timeout          | 10                |

| init_connect             |                   |

| max_connect_errors       | 10                |

| max_connections          | 151               |

| max_user_connections     | 0                 |

+--------------------------+-------------------+

7 rows in set (0.00 sec)

mysql> show variables like "%timeout%";

+----------------------------+-------+

| Variable_name              | Value |

+----------------------------+-------+

| connect_timeout            | 10    |

| delayed_insert_timeout     | 300   |

| innodb_lock_wait_timeout   | 50    |

| innodb_rollback_on_timeout | OFF   |

| interactive_timeout        | 28800 |

| net_read_timeout           | 30    |

| net_write_timeout          | 60    |

| slave_net_timeout          | 3600  |

| table_lock_wait_timeout    | 50    |

| wait_timeout               | 28800 |

+----------------------------+-------+

10 rows in set (0.00 sec)

mysql> show variables like "%buffer%";

+-------------------------+---------+

| Variable_name           | Value   |

+-------------------------+---------+

| bulk_insert_buffer_size | 8388608 |

| innodb_buffer_pool_size | 8388608 |

| innodb_log_buffer_size  | 1048576 |

| join_buffer_size        | 131072  |

| key_buffer_size         | 8384512 |

| myisam_sort_buffer_size | 8388608 |

| net_buffer_length       | 16384   |

| preload_buffer_size     | 32768   |

| read_buffer_size        | 131072  |

| read_rnd_buffer_size    | 262144  |

| sort_buffer_size        | 2097144 |

| sql_buffer_result       | OFF     |

+-------------------------+---------+

12 rows in set (0.00 sec)

mysql> show variables like "%err%";

//使用通配符查mysql错误日志存放位置，

//跟配置文件my.cnf里面的“[mysqld_safe]log-error=/var/log/mysqld.log”吻合

+--------------------+---------------------+

| Variable_name      | Value               |

+--------------------+---------------------+

| error_count        | 0                   |

| log_error          | /var/log/mysqld.log |

| max_connect_errors | 10                  |

| max_error_count    | 64                  |

| slave_skip_errors  | OFF                 |

+--------------------+---------------------+

5 rows in set (0.00 sec)

mysql> exit

Bye

# cat /etc/my.cnf

[mysqld]

datadir=/var/lib/mysql

socket=/var/lib/mysql/mysql.sock

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

mysql> repair table databasename.tablename;//修复表

mysql> repair table discuz.pre_forum_post;

+-----------------------+--------+----------+----------+

| Table                 | Op     | Msg_type | Msg_text |

+-----------------------+--------+----------+----------+

| discuz.pre_forum_post | repair | status   | OK       |

+-----------------------+--------+----------+----------+

1 row in set (0.00 sec)