I use KDE almost always, but on my main laptop I always install GNOME in the Opensuse installation, just in case I want to take it for a spin. Unfortunately this seems to have also installed something called 'tracker' that is meant to be a desktop indexing and search service for GNOME. Even when I login to KDE this tracker thing starts up and spends ages eating 100% CPU time of one of the laptop's cores, not to mention thrashing the disk.
Luckily the fix is simple:
Edit /etc/xdg/autostart and add the following line to the tracker-*.desktop files:
After that the tracker-store etc. processes will no longer start up when you login, you'll need to logout and log back in for the change to take affect of course.
Maybe one day one of these Linux desktop search things will work without killing the performance of the machine it runs on and thereby destroying the user experience it's supposed to enhance.