Re: SET ROLE and reserved roles

Amit Langote <Langote_Amit_f8@lab.ntt.co.jp> writes:
> I observe this:

> postgres=# SET ROLE TO NONE;
> SET
> postgres=# SET ROLE TO nonexistent;
> ERROR:  role "nonexistent" does not exist
> postgres=# SET ROLE TO pg_signal_backend;
> ERROR:  invalid value for parameter "role": "pg_signal_backend"

> Is that behavior deliberate? Might it be better to handle the case
> specially much as setting to "none" works?

What I'd like to know is why it rejects that at all.  What's the point
of having roles you can't SET to?
        regards, tom lane