MySQL consuming all memory on Rasperry Pi4

I recently installed mysql on my Raspberry Pi4. Recently, it seems to be consuming all memory and makes the Raspberry more or less unresponsive.

Here’s a screenshot of htop:
htop

As for config files, I’ve followed this example for the /etc/mysql/mariadb.conf.d/50-server.cnf file, and my /etc/mysql/my.cnf contains only:

[client-server]
# Import all .cnf files from configuration directory
!includedir /etc/mysql/conf.d/
!includedir /etc/mysql/mariadb.conf.d/

I’d be grateful if someone could point me in the right direction as I’m stuck for some time now, thanks!