Change temporary tables in mySQL to memory

To change the location of temporary tables in mySQL, we need to edit the tmpdir variable in my.cnf or which ever file contains the [mysqld] section.

tmpdir = /run

Assuming /run is a tmpfs filesystem (use df to find out) [go here to setup a tmpfs Ramdisk]

Of course, we could use the above to change the location to another physical disk if we so desired.

sudo mysqld --verbose --help will show us that this change has taken effect.

Note on Slackware 14.2 this was;

sudo /usr/libexec/mysqld --verbose --help

Note: we must restart mysql for any changes to take effect;

/etc/rc.d/rc.mysql stop/start

systemctl stop/start mysql

service mysql stop/start

Note, these days it would seem that we dont have the same cnf files as we once did. Perhaps I'm having a senior moment, but I do recall copying over a template cnf file to /etc/my.cnf and modifying, these days the same file is there but seems to be nearly a placeholder with a couple of include directories.

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Examples of some cnf files from an older version of Slackware can be found here