Memory exhausted in AllocSetAlloc()

In dumping some tables to tape, my "copy" died with the
message:

FATAL 1:  Memory exhausted in AllocSetAlloc()
PQendcopy: resetting connection

This is 6.5.2 on Linux.  The tables are about 15Gb.
Any of the gurus have any suggestions on what to do?
Or how to diagnose the underlying problem?  I'm running
PGDEBUG=2 but there are no additional clues . . .

Thanks,

--Martin

===========================================================================

Martin Weinberg                      Phone: (413) 545-3821
Dept. of Physics and Astronomy       FAX:   (413) 545-2117/0648
530 Graduate Research Tower         weinberg@astro.umass.edu
University of Massachusetts         http://www.astro.umass.edu/~weinberg/
Amherst, MA  01003-4525