Hi,
i tried a simple test:
create temp table _t as select repeat('x',382637520) as test;
update _t set test=test||test;
pg 8.3 32bit fails with
[Error Code: 0, SQL State: 53200] ERROR: out of memory
Detail: Failed on request of size 765275088.
pg 8.4.4 64bit works fine
so upgrade to 64bit
regards
Thomas