mysql8学习手册第四部分：mysql配置文件的使用和高级配置

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第四章：Configuring Mysql

• Using config file
• Using global and session variables
• Using parameters with startup script
• Configuring the parameters
• Changing the data directory

mysql有两种参数：Static(重启生效)和Dynamic（不用重启即可生效）

mysql变量设置：

1. Config file

2. Startup script

3. Using SET command

4. Using config file
   The default config file is /etc/my.cnf (on Red Hat and CentOS systems) and /etc/mysql/my.cnf (Debian systems)

mysql配置参考样例：

[mysqld] <---section name
 =  <---parameter values
[client]
 = 
[mysqldump]
 = 
[mysqld_safe]
 = 
[server]
 = 

• [mysql] : Section is read by the mysql command-line client
• [client] : Section is read by all connectingclients (including mysql cli )
• [mysqld] : Section is read by the mysql server
• [mysqldump] : The section is read by the backuputility called mysqldump
• [mysqld_safe] : Read by the mysqld_safe process(MySQL Server Startup Script)

2. Using global and session variables

Global: Applies to all the new connections
Session: Applies only to the current connection

SET GLOBAL long_query_time = 1;
SET PERSIST long_query_time = 1;
SET @@persist.long_query_time = 1;
SET SESSION long_query_time = 1;