Comment 6 for bug 1973382

There is also the --restart-after-upgrade option to dh_installsystemd, which the manpage says "This is the default behaviour in compat 10." And we're using compat 13....

Of course, the postgresql-common package doesn't actually ship the daemon; that's shipped in the versioned 'postgresql' package. So perhaps the concerns about not restarting on upgrade of postgresql-common are moot, as long as the versioned package itself handles restarting?