**Operating system: ** Ubuntu 20.04.1
Webmin > Servers > MySQL Database Server > MySQL Server Configuration
Change “Sort buffer size” from
[*] 1 [Mb]
Save and Restart MySQL
Results in a wrecked MySQL that can not start.
Upon investigation it looks like Webmin wrote garbage into /etc/mysql/mysql.conf.d/mysqld.cnf
set-variable = sort_buffer_size=1M
That’s invalid and stopped MySQL from being able to start, which in turn leaves the entire MySQL admin section of Webmin inaccessible, and therefor impossible to even attempt to revert the change through Webmin’s UI.
Manually editing that file so the line reads:
allowed MySQL to be able to restart. Chasing down where that setting was actually edited in the filesystem was … fun.