Experience-mysql configuration file reading order problem!

Reason:

The MySQL command can be used to connect to the server, but where the data is usually stored, the parameters are set, which requires knowing which configuration file is used by MySQL. (usually my.cnf this configuration problem)

Therefore, it is necessary to clear the MY.CNF loading order.

Default load Order:

/ETC/MY.CNF	global Options
/ETC/MYSQL/MY.CNF
SYSCONFDIR /my.cnf	global Options
$MYSQL _home/my.cnf	server-specific options
defaults-file|extra-file	the file specified with --defaults-extra-file=path ...
~/my.cnf	User-specific Options

Reading order

1,/ETC/MY.CNF

The general configuration file will be here, of course, when MySQL starts the service, it will read the configuration file by default. (multi-instance MySQL to be cautious!) ）

2./etc/mysql/my.cnf

一般系统etc并没有mysql这个目录，如果需要自己创建。


3, SYSCONFDIR /my.cnf

basedir/my.cnf

4, $MYSQL _home/my.cnf

datadir/my.cnf

5, plus start the specified parameters

-defaults-file=#, read only the specified file (no longer read other configuration files)

-defaults-extra-file=#, read the global configuration from other higher-priority profiles before reading the specified configuration file.

6、~/my.cnf

Tips:

1, assume that 4 configuration files are present, also use the--defaults-extra-file specified parameter file, if there is a "parameter variable" in the 5 configuration file appears, then the parameter value in the configuration file will overwrite the parameter variable value in the previous configuration file, This means that the value set in ~/.MY.CNF is used.

2、/usr/local/mysqltwo/bin/mysqld--verbose--help |grep-a 1 ' Default options '

Without excluding the version of the problem, some paths will be different. For example, some paths are my.cnf under/usr

The specific reading order can be based on your own version and official manuals!

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Experience-mysql configuration file reading order problem!