back-end dies on select

prodex=# select category_id, category_name from category natural join category_product natural join product;
pqReadData() -- backend closed the channel unexpectedly.
        This probably means the backend terminated abnormally
        before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!#


That's the first time anything like this has happened... no doubt I
have the join syntax wrong (I don't normally use natural joins) but it
shouldn't bring down my connection, should it?

--
Matt Beauregard
Information Technology Operations, DesignScape

Ph: +61 2 9361 4233   Fx: +61 2 9361 4633