Re: WITH NOT MATERIALIZED and DML CTEs

On Monday, June 3, 2019 11:50:15 A.M. EDT Andres Freund wrote:
> > This seems like an omission to me.  Ideally, the presence of an
> > explicit "NOT MATERIALIZED" clause on a data-modifying CTE should
> > disable the "run to completion" logic.
> 
> I don't see us ever doing that. The result of minor costing and other
> planner changes would yield different updated data. That'll just
> create endless bug reports.

I understand why the rule exists in the first place, but I think that an 
explicit opt-in signals the assumption of responsibility and opens the 
possibility of using this in a well-defined evaluation context, such as 
CASE WHEN.

                              Elvis