On Tue, Nov 20, 2012 at 8:38 PM, Craig Ringer <craig@2ndquadrant.com> wrote:
> On 11/21/2012 12:06 AM, Claudio Freire wrote:
>> 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).
> Because people are now used to using CTEs as query hints, it'd probably
> cause performance regressions in working queries. Perhaps more
> importantly, Pg would have to prove that doing so didn't change queries
> that invoked functions with side-effects to avoid changing the results
> of currently valid queries.
Fair point. Will look into it a bit.