In some OS, particularly Ubuntu and sometimes Debian, depending on the exact sequence of previous installations of Python (or lack thereof), particularly of Python3, a restart operation can fail and would require a complete re-installation.

Failing command: systemctl restart mariadb-columnstore

Workaround: sudo apt install python prior to installing the software

Some analysis: columnstore package depends on python | python2 | python3 so as far as apt-get is concerned, any python package will do
but the script has #!/usr/bin/python — so only package that provides this binary will actually work

depending on how lucky you are apt-get might chose the correct one. Or not.
in particular, python3 only installs /usr/bin/python3