Determine which MySQL configuration file is being used

Taken from the fantastic "High Performance MySQL" O'Reilly book:

$ which mysqld
/usr/sbin/mysqld

$ /usr/sbin/mysqld --verbose --help | grep -A 1 "Default options"
Default options are read from the following files in the given order:
/etc/mysql/my.cnf ~/.my.cnf /usr/etc/my.cnf

If you run mysql --verbose --help | less it will tell you about line 11 which .cnf files it will look for.

You can also do mysql --print-defaults to show you how the configuration values it will use. This can also be useful in identifying just which config file it is loading.

If you are on Linux, then start the 'mysqld' with strace, for eg strace ./mysqld.

Among all the other system calls, you will find something like:

stat64("/etc/my.cnf", 0xbfa3d7fc)       = -1 ENOENT (No such file or directory)
stat64("/etc/mysql/my.cnf", {st_mode=S_IFREG|0644, st_size=4227, ...}) = 0
open("/etc/mysql/my.cnf", O_RDONLY|O_LARGEFILE) = 3

So, as you can see..it lists the .cnf files, that it attempts to use and finally uses.

I am on Windows and I have installed the most recent version of MySQL community 5.6

What I did to see what configuration file uses was to go to Administrative Tools > Services > MySQL56 > Right click > Properties and check the path to executable:

"C:/Program Files/MySQL/MySQL Server 5.6/bin\mysqld" --defaults-file="C:\ProgramData\MySQL\MySQL Server 5.6\my.ini" MySQL56

An alternative is to use

mysqladmin variables