Comment # 5 on bug 1130161 from Benjamin Zeller

Must be a side effect of running inside your container. I cannot see a memory
usage like that for a zypper search run on my machine directly. 

Can you provide the steps to reproduce your test env? Or is it just a plain
OpenSUSE Tumbleweed container running in a default LXC container?

Also once zypper exits there is no way it can still use up any memory since the
kernel will clean up all ressources that are allocated by the process. So if
the mem consumption of your container stays high even after zypper exits there
is something else wrong here.