Specifying Program Options •Option File Syntax •Option File Inclusions 346 On Unix platforms, MySQL ignores configuration files that are world-writable. This is intentional as a security measure. On Unix and Unix-like systems, MySQL programs read startup options from the files shown in the following table, in the specified order (files listed first are read first, files read later take precedence). BASEDIR  represents the MySQL base installation directory. When MySQL 8.0 has been installed using MySQL Installer, this is typically  C:\ PROGRAMDIR \MySQL\MySQL 8.0 Server  where  PROGRAMDIR represents the programs directory (usually  Program Files  on English-language versions of Windows), See Section 2.3.3, “MySQL Installer for Windows” . DATADIR  represents the MySQL data directory. As used to find  mysqld-auto.cnf , its default value is the data directory location built in when MySQL was compiled, but can be changed by  --datadir specified as an option-file or command-line option processed before  mysqld-auto.cnf  is processed. %APPDATA%  represents the value of the Windows application data directory. Use the following command to determine its exact location from the value of the  APPDATA  environment variable: In the preceding table,  %WINDIR%  represents the location of your Windows directory. This is commonly C:\WINDOWS . Use the following command to determine its exact location from the value of the  WINDIR environment variable: Note C:\>  echo %APPDATA% C:\>  echo %WINDIR% File Name Purpose %WINDIR%\my.ini ,  %WINDIR%\my.cnf Global options C:\my.ini ,  C:\my.cnf Global options BASEDIR \my.ini ,  BASEDIR \my.cnf Global options defaults-extra-file The file specified with  --defaults-extra-file , if any %APPDATA%\MySQL\.mylogin.cnf Login path options (clients only) DATADIR \mysqld-auto.cnf System variables persisted with  SET PERSIST  or SET PERSIST_ONLY  (server only) MySQL looks for option files in the order described in the following discussion and reads any that exist. If an option file you want to use does not exist, create it using the appropriate method, as just discussed. On Windows, MySQL programs read startup options from the files shown in the following table, in the specified order (files listed first are read first, files read later take precedence). For information about option files used with NDB Cluster programs, see Section 23.3, “Configuration of NDB Cluster” . Table 4.1 Option Files Read on Windows Systems Note Option File Processing Order