FWIW I had mem issues on openHABian on Raspis, too, when moving to OH4.
Regular mem usage increased by ~30% - deadly if on an 1GB RPi3. My java proc size is now 1,3G.
All I effectively changed was the JDK. I’m still on bullseye ie Debian 11.
Maybe it’s doing 64bit by default now, just a guess.
64bit on RPI is a real bummer, vastly increases mem usage without benefits. Docker or not.
You likely won’t notice on x86 as it has been 64bit ever there
The PR is merged and I also rebuild the official openHAB 3.4.4 and 4.0.0.M4 images.
These memory issues also occured for me on another project where the only change was upgrading the amd64 base images from Debian 11 to 12. When you run several containers those increased memory demands really add up.
FWIW if you Google a bit there are more users complaining about increased Debian 12 memory demands.
Be careful not to attribute it to Debian right away. As I said I still run 11 and see the same symptom. Might be the same cause as yours or not butD12 will have a different JDK package so that’s the common ground and I’d look there first.