8.4: COPY continues after client disconnects

Using PostgreSQL 8.4.13 on ScientificLinux 6.3 (x86_64), I noticed
that a pg_dump ran out of (local) disk space.
However, the server was still using CPU and disk resources. An strace
clearly showed this pattern:

read(....) = 8192
sendto(...) = -1 EPIPE
-- SIGPIPE (Broken pipe) @ ....

The server does detect the broken pipe. It logs the following messages:

637 LOG: 08006: could not send data to client: Connection reset by peer
638 LOCATION: internal_flush, pqcomm.c:1108
639 STATEMENT: COPY ... to stdout;
640 LOG: 08006: could not send data to client: Broken pipe
641 LOCATION: internal_flush, pqcomm.c:1108
642 STATEMENT: COPY ... to stdout;

it ran until I killed it.

--
Jon