Hi, On 2019-01-12 07:58:39 +1300, Thomas Munro wrote: > On Sat, Jan 12, 2019 at 7:19 AM Andres Freund <and...@anarazel.de> wrote: > > On 2019-01-11 11:12:25 -0500, Robert Haas wrote: > > > I actually think that we should go "all in" here and allow the user to > > > specify either that they want materialization or that they don't want > > > materialization. If they specify neither, then we make some decision > > > which we may change in a future release. If they do specify > > > something, we do that. > > > > +many > > I think the syntax as proposed is almost OK if we only want to > grandfather in our historically hintful CTEs but discourage the > development of any future kinds of hints. Even then I don't love the > way it formalises a semi-procedural step at the same language level as > a glorious declarative relational query. > > Maybe we could consider a more extensible syntax that is attached to > the contained SELECT rather than the containing WITH. Then CTEs would > be less special; there'd be a place to put hints controlling top-level > queries, subselects, views etc too (perhaps eventually join hints, > parallelism hints etc, but "materialize this" would be just another > one of those things). That'd be all-in.
I think you have some purity arguments here, but the likelihood of us developing a full-blown solution is not that high, and the lack of inlinable CTEs is *really* hurting us. As long as the design doesn't block a full solution, if we go there, I think it's a very acceptable blemish in comparison to the benefits we'd get. Greetings, Andres Freund