On Tue, Nov 20, 2012 at 12:23 PM, Merlin Moncure <mmoncure@xxxxxxxxx> wrote: > On Tue, Nov 20, 2012 at 9:10 AM, Claudio Freire <klaussfreire@xxxxxxxxx> wrote: >> On Tue, Nov 20, 2012 at 12:04 PM, Merlin Moncure <mmoncure@xxxxxxxxx> wrote: >>> The problem here is very clear. Oracle is optimizing through the CTE. >>> PostgreSQL does not do this by design -- CTE's are used as a forced >>> materialization step. >> >> While I love that design (it lets me solve lots of problems for huge >> queries), wouldn't pushing constraints into the CTE be a rather safe >> optimization? > > sure, or rewrite query as classic join. I meant for postgres to do automatically. Rewriting as a join wouldn't work as an optimization fence the way we're used to, but pushing constraints upwards can only help (especially if highly selective). -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
