diable update-apt-xapian-index on ubuntu

tl;dr:
$ chmod a-x /etc/cron.weekly/apt-xapian-index;
$ echo 'APT::Periodic::Enable "0";' >> /etc/apt/apt.conf.d/99kp-periodic;

dłuższa wersja:

add:

APT::Periodic::Enable "0";
APT::Periodic::Update-Package-Lists "0";
APT::Periodic::Unattended-Upgrade "0";
APT::Periodic::Download-Upgradeable-Packages "0";

to a file called /etc/apt/apt.conf.d/99periodic-disable (I picked that name. You can change it, as long as you keep the 99 in front, if you don't like it).