Akonadi was running on Debian KDE 5.20.5 and netdata app reported sql usage 10GB+ of memory and when i did "ps aux|grep sql" i have found akonadi processes.
Processes in htop looked like this.

Based on answers from: https://askubuntu.com/questions/762062/akonadi-services-and-mysqld-use-too-much-memory-in-kubuntu-16-04
Command "akonadictl stop" freed 2GB of "Committed Memory" per netdata - such memory is said to be the sum of all memory which has been allocated by processes.

"sudo apt-get remove --purge kmail akonadi-server" freed 50MB disk:

Removing task-kde-desktop (3.68+deb11u1) ...
Removing kde-standard (5:111) ...
Removing kmail (4:20.08.3-1) ...
Removing korganizer (4:20.08.3-1) ...
Removing kaddressbook (4:20.08.3-1) ...
Removing knotes (4:20.08.3-1) ...
Removing kdepim-runtime (4:20.08.3-1) ...
Removing akonadi-server (4:20.08.3-3) ...

(i am not using any of these i think)
Isn't 2GB freed memory suspicious high while i am not aware of using any mentioned removed utilities?