It seems like the consensus over at another discussion on this topic [1] is that we ought to go ahead and print the zeros [for machine readable output formats], even though that creates some interesting scenarios like the fact that disk sorts will print 0 for memory even though that's not true.
The change has already been made and pushed for hash disk spilling, so I think we ought to use Justin's patch here. James [1] https://www.postgresql.org/message-id/2276865.1593102811%40sss.pgh.pa.us
