"David G. Johnston" <david.g.johns...@gmail.com> writes: > On Tue, May 9, 2017 at 12:36 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> Also, considering that this behavior has been there since 8.4, >> I think it's sheerest chutzpah to claim that changing the docs in >> v10 would materially reduce the backward-compatibility concerns >> for whatever we might do in v11.
> No it won't, but those who are using 10 as their first version would > probably be happy if this was covered in a bit more depth. I think the existing doc text is perfectly clear (while David's proposed replacement text is not). > Even a comment > like "Unlike most other DBMS PostgreSQL presently executes the subquery in > the CTE in relative isolation. It is suggested that you document any > intentional usage of this optimization fence as a query planning hint so > that should the default change in the future you can update the query to > support whatever official syntax is implemented to retain this behavior. Well, TBH that is pre-judging what (if anything) is going to be changed by a feature that we don't even have design consensus on, let alone a patch for. I don't think that's an improvement or a good service to our users; it's just promoting confusion. I think that until we do have a design and a patch, we're better off leaving the docs reading the way they have for the past eight years. I'm also a bit mystified by the apparent urgency to change something, anything, in this area when we're already past feature freeze. This would be a fit subject for discussion several months from now when v11 development opens, but right now it's just distracting us from stabilizing v10. regards, tom lane -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers