BUG #6088: copy to stdout cannot be stopped with kill(pid) or pg_terminate_backend

The following bug has been logged online:

Bug reference:      6088
Logged by:          Maksym Boguk
Email address:      Maxim.Boguk@gmail.com
PostgreSQL version: 8.4.7
Operating system:   Freebsd
Description:        copy to stdout cannot be stopped with kill(pid) or
pg_terminate_backend
Details:

Again I not sure it is actual bug or intended behaviour.

But I found I can not stop
COPY bill.changes (id, cdate, mdate, status, table_name, pk_id, old_row,
new_row) TO stdout;
with pg_terminate_backend(procpid) or kill (procpid).

At the same time copy to stdout completely ignore fact other side (pg_dump
itself) was killed long time ago.

That is can be problem because backup of some huge table can be very long
process and prevent any DDL changes for all tables in the that database
(because pg_dump keep lock on all tables).

Now I'm sitting with open ssh and waiting 2 hour while that 120Gb table
finally finish copying and I can perform some urgent DDL on the database.