A co-worker of mine was doing the same thing with DB2. What he found was each time he did an insert that it was creating a new cursor for each insert. That slowed the process down.

What he ended up doing was turning auto-commit off, and then using DBI transaction control (begin_work() and commit() ) and would 'commit' every 1000 rows. It went from taking 8 hours to 4 hours, so a slight improvement.

I don't know if Postgre will act in the same manor but it would be worth a shot...