Re: elog(FATAL)ing non-existent roles during client authentication

Gavin Sherry <swm@linuxworld.com.au> writes:
> I wonder if we should check if the role exists for the other
> authentication methods too? get_role_line() should be very cheap and it
> would prevent unnecessary authentication work if we did it before
> contacting, for example, the client ident server. Even with trust, it
> would save work because otherwise we do not check if the user exists until
> InitializeSessionUserId(), at which time we're set up our proc entry etc.

This only saves work if the supplied ID is in fact invalid, which one
would surely think isn't the normal case; otherwise it costs more.

I could see doing this in the ident path, because contacting a remote
ident server is certainly expensive on both sides.  I doubt it's a good
idea in the trust case.
        regards, tom lane