Kenan Yao <kyao(at)pivotal(dot)io> writes:
> -- mkfifo /tmp/test.dat # bash
> copy pg_class to '/tmp/test.dat';
> -- try pg_cancel_backend or pg_terminate_backend from other sessions
This does not seem like a supported case to me. I see few if any reasons
to want to do that rather than doing copy-to-program or copy-to-client.
We're certainly not going to want to add any overhead to the COPY code
paths in order to allow it.
regards, tom lane