On Mon, May 25, 2009 at 11:22 AM, David Blewett <david@xxxxxxxxxxxxxxxx> wrote: > On Sun, May 24, 2009 at 2:42 PM, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: >> >> It still feels like this schema design is obscuring correlations that >> the planner needs to know about in order to make decent estimates. > > I'm not sure how to make the planner aware of these correlations. Is there > something inherently flawed with this design? It seems pretty close to the > one on the Varlena website [1]. > >> You mentioned earlier that the seemingly unrelated question_ids were >> linked via a common submission_id. I wonder whether it's possible to >> query using the submission_id instead? > > Well, I do join the different response tables [text/date/etc] together via > the submission_id. However, in order to be able to apply the where clauses > appropriately, I have to limit the responses to the appropriate > question_id's. Would it matter to push that requirement down to the where > clause instead of part of the join clause? > > David > > 1. http://www.varlena.com/GeneralBits/110.php > Anyone have thoughts on this? Bueller? David -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
