Robert Haas <robertmhaas@gmail.com> writes:
> I think this line of thinking is on the right track. The server
> should certainly not send back an immediate ERROR response, because
> that will definitely confuse the client. Of course, any subsequent
> commands will report ERRORs until the client rolls back. But it also
> seems highly desirable for the server to send some sort of immediate,
> asynchronous notification, so that a sufficiently smart client can
> immediately report the error back to the user or take such other
> action as it deems appropriate.
If you must have that, send a NOTICE. I don't actually see the point
though. If the client was as smart and well-coded as all that, it
wouldn't be sitting on an open transaction in the first place.
> Currently, it appears that the only messages that the server can send
> back asynchronously are ParameterStatus and NotificationResponse.
Using either of those is completely inappropriate.
regards, tom lane