MySQLread_only与super_read_only之间的关系 [数据库教程]

database

目录

  • super_read_only = 0, read_only=0
  • super_read_only=0, read_only=1
  • super_read_only=1, read_only=0
  • super_read_only=1, read_only=1
  • super_read_only = 0, read_only=0
  • super_read_only = 1, read_only=0
  • super_read_only = 0, read_only=1
  • super_read_only = 1, read_only=1
  • 总结

read_only 表示是否允许普通用户写入。如果为on,表示禁止普通用户写入。

super_read_only 表示是否禁止超级用户写入,包括普通用户,即针对所有用户。

默认关闭。

如果打开 super_read_only,则read_only会自动打开。

如果关闭 read_only,则 super_read_only 会自动关闭。

下面做下测试。

super_read_only = 0, read_only=0

查看当前值:

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 0 | 0 |

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

1 row in set (0.01 sec)

设置super_read_only=1之后,查看read_only的变化。

>set global super_read_only=1;

Query OK, 0 rows affected (0.00 sec)

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 1 | 1 |

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

1 row in set (0.01 sec)

read_only变为1。

超级用户设置为只读后,自然普通用户也会设置只读。

super_read_only=0, read_only=1

查看当前值:

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 0 | 1 |

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

1 row in set (0.00 sec)

设置 super_read_only=1后, 查看read_only 变化。

>set global super_read_only=1;

Query OK, 0 rows affected (0.00 sec)

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 1 | 1 |

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

1 row in set (0.00 sec)

read_only无变化。

super_read_only=1, read_only=0

不存在这种情况。

super_read_only=1, read_only=1

查看当前值:

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 1 | 1 |

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

1 row in set (0.00 sec)

设置super_read_only = 0之后, 查看read_only变化。

>set global super_read_only=0;

Query OK, 0 rows affected (0.01 sec)

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 0 | 1 |

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

1 row in set (0.00 sec)

super_read_only = 0, read_only=0

查看当前值:

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 0 | 0 |

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

1 row in set (0.01 sec)

设置read_only=1之后,查看super_read_only 有无变化。

>set global read_only=1;

Query OK, 0 rows affected (0.00 sec)

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 0 | 1 |

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

1 row in set (0.00 sec)

super_read_only = 1, read_only=0

不存在这种情况。

super_read_only = 0, read_only=1

查看当前值:

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 0 | 1 |

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

1 row in set (0.00 sec)

设置 read_only=0后,查看super_read_only有无变化。

>set global read_only=0;

Query OK, 0 rows affected (0.00 sec)

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 0 | 0 |

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

1 row in set (0.01 sec)

super_read_only变为 0。

普通用户关闭只读,超级用户的只读(也包括普通用户)也自然会关闭只读。

super_read_only = 1, read_only=1

查看当前值:

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 1 | 1 |

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

1 row in set (0.01 sec)

设置read_only=0之后,查看 super_read_only的变化。

>set global read_only=0;

Query OK, 0 rows affected (0.00 sec)

>select @@super_read_only, @@read_only;

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

| @@super_read_only | @@read_only |

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

| 0 | 0 |

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

1 row in set (0.01 sec)

super_read_only变为 0。

总结

关于 read_only 与 super_read_only之间的关系,实际上从其定义就可以明白。

基础很重要。

MySQL read_only 与 super_read_only 之间的关系

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