MySQL Variables super_read_only 数据库 参数变量解释及正确配置使用

本站中文解释

super_read_only参数是MySQL服务器用于只读状态的参数，可用于以下各种场景：

1.在备库运行MySQL服务器以保证数据库容灾：备库上设置super_read_only参数为ON，只允许服务器端运行应用程序，而不允许客户端连接查询。

2.在生产环境时控制DML查询：为了控制用户的DML查询，可以设置super_read_only参数为ON，仅允许某些用户执行更新操作。

3.用于运行唯读复制：MySQL 稳定版 5.7及之前的版本中，无法禁止binlog的写，而super_read_only参数的存在，可以方便的解决这一问题，使备库在只读模式下正常运行，这样就可以实现唯读复制。

设置super_read_only参数： 进入MySQL控制台，在mysql>提示符下执行以下两条命令：

SET GLOBAL super_read_only=1;

FLUSH PRIVILEGES;

官方英文解释

super_read_only

If the read_only system
variable is enabled, the server permits no client updates
except from users who have the
SUPER privilege. If the
super_read_only system
variable is also enabled, the server prohibits client updates
even from users who have SUPER.
See the description of the
read_only system variable for
a description of read-only mode and information about how
read_only and
super_read_only interact.

Client updates prevented when
super_read_only is enabled
include operations that do not necessarily appear to be
updates, such as CREATE FUNCTION (to
install a loadable function) and INSTALL
PLUGIN. These operations are prohibited because they
involve changes to tables in the mysql
system database.

Changes to super_read_only on
a replication source server are not replicated to replica
servers. The value can be set on a replica independent of the
setting on the source.