On Tue, Apr 16, 2013 at 10:51 PM, François Beausoleil <francois@teksol.info> wrote:
INSERT INTO persona_followers(service_id, follower_id, valid_at) SELECT service_id, follower_id, NOW() FROM (SELECT DISTINCT service_id, follower_id FROM import) AS import WHERE NOT EXISTS(SELECT * FROM persona_followers WHERE import.service_id = persona_followers.service_id AND import.follower_id = persona_followers.follower_id);
Try this for your insert query instead:
insert into persona_followers( service_id, follower_id, valid_at )
select i.service_id, i.follower_id, now()
from import i
left join persona_followers pf on i.service_id = pf.service_id and i.follower_id = pf.follower_id
where pf.service_id is null
order by 1,2;
This will insert only those rows that are not already present, and involves no subqueries and only one join.
--
Moshe Jacobson Nead Werx, Inc. | Manager of Systems Engineering
