BUG #4804: ERROR out of memory on select bytea field legth about 120Mb

The following bug has been logged online:

Bug reference:      4804
Logged by:          Vadim Fedorenko
Email address:      junk@fromru.com
PostgreSQL version: 8.3.3
Operating system:   Windows 2003 Server R2 64bit
Description:        ERROR out of memory on select bytea field legth about
120Mb
Details:

Hi!

I have a database about 4Gb and pg_dump fails with

ERROR:  out of memory
DETAIL:  Failed on request of size 536870912.

on it.

I found out that it fails on selecting bug bytea field:

select length(binarydata) from config where datasize >120000000
results 138124811

and

select binarydata from config where datasize >120000000

results
ERROR:  out of memory
DETAIL:  Failed on request of size 536870912.

how can I workaround this?