Most efficient way of updating table from another - Postgres
The fastest way will probably be to create a new table based on a join of the existing tables, create indexes and foreign keys constraints, and then drop the old "interface_events" and rename the new table into place.  Views and foreign keys into this table can complicate this.

create interface_events_temp as 
    select interface_events.*, device.interface_id from interface_events 
        join device on (device.id = interface_events.device_id)


But the interface_events.* notation relies on interface_id not already existing in interface_events.  Since it already exists, you would have to list out all columns in interface_events except for interface_id.