Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> writes:
> To get the current role, psql would have to query the database whenever
> it displays the prompt. That would be rather expensive...
See previous discussion:
https://www.postgresql.org/message-id/flat/CAFj8pRBFU-WzzQhNrwRHn67N0Ug8a9-0-9BOo69PPtcHiBDQMA%40mail.gmail.com
At the time I didn't like the idea too much, but now that we've seen
a second independent request, maybe our opinion of its value should
go up a notch.
regards, tom lane