> but then to get the entirely new items out i use a sub query which takes
> for ever
>
> SELECT DISTINCT * FROM v_postcode_new WHERE postcode NOT IN ( SELECT
> postcode FROM v_postcode_old ) ORDER BY postcode ASC;
NOT IN is known to be very, very slow in Postgres. Use NOT EXISTS instead:
SELECT DISTINCT * FROM v_postcode_new vpn WHERE NOT EXISTS (SELECT TRUE FROM
v_postcode_old vpo WHERE vpo.postcode=vpn.postcode) ORDER BY postcode ASC;
Chris