> From: Kevin Grittner [mailto:kgri...@mail.com] > > I think I'm right in thinking that if a unique index exists to match > > the group by clause, and the join condition is equality (probably > > using the same operator class as the unique btree index?), then the > > grouping could be pushed up to before the join. > > Off-hand, it seems equivalent to me; I don't know how much work it would > be. > > Out of curiosity, does the first query's plan change if you run this instead?: > > SELECT s.product_code,SUM(s.quantity) > FROM products p > INNER JOIN bigsalestable s ON p.productid = s.productid GROUP BY > s.product_code; >
I should have made it more clear about the lack of product_code in the bigsalestable, there's only productid, the lookup to the product table was to obtain the actual more user friendly product_code. The actual table def's are in the attachment of the original email. Regards David Rowley > -Kevin -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
