The MySQL server has many operating parameters, which you can change at server startup using command-line options or configuration files (option files). It is also possible to change many parameters at runtime. For general instructions on setting parameters at startup or runtime, see Section 5.1.4, “Server Command Options”, and Section 5.1.5, “Server System Variables”.
On Windows, MySQL Installer interacts with the user and creates a
my.ini in the base installation
directory as the default option file. If you install on Windows
from a Zip archive, you can copy the
my-default.ini template file in the base
installation directory to
my.ini and use the
latter as the default option file.
As of MySQL 5.7.18,
my-default.ini is no
longer included in or installed by distribution packages.
On Windows, the
.cnf option file extension might not be
After completing the installation process, you can edit the
default option file at any time to modify the parameters used by
the server. For example, to use a parameter setting in the file
that is commented with a
# character at the
beginning of the line, remove the
#, and modify
the parameter value if necessary. To disable a setting, either add
# to the beginning of the line or remove it.
For non-Windows platforms, no default option file is created during either the server installation or the data directory initialization process. Create your option file by following the instructions given in Section 4.2.6, “Using Option Files”. Without an option file, the server just starts with its default settings—see Section 5.1.2, “Server Configuration Defaults” on how to check those settings.
For additional information about option file format and syntax, see Section 4.2.6, “Using Option Files”.