out of memory error with large insert

Hi

On a large transaction involving an insert of 8 million rows, after a while Postgres complains of an out of memory error.

Failed on request of size 32

I get no other message.

Shmmax is set to 1 Gb

Shared_buffers set to 50000

Max memory on box is 4Gb..Postgres is the only major application running other than a jvm with minimal heap.

Other than breaking this transaction into smaller bits(which may not be possible as this scenario is not encountered often), am I missing something.

Sriram