A job keeps the client address of its submission (Operation.client_ip,
migration operations.0003); the rows the worker writes for it, including the
migration's and the VM delete's own rows, carry it. A cancel is written under
the user who asked and from their address, also when an administrator
cancels another user's job; a running job's cancel gets a row when asked,
and its end a row when it stops. A resolution carries the administrator's
address.
