Re: CTE optimization fence on the todo list?

On 05/01/2015 07:24 PM, Josh Berkus wrote:
> O
>> (A possible compromise position would be to offer a new GUC to
>> enable/disable the optimization globally; that would add only a reasonably
>> small amount of control code, and people who were afraid of the change
>> breaking their apps would probably want a global disable anyway.)
> We'd need the GUC.  I know of a lot of cases where people are using WITH
> clauses specifically to override the query planner, and requiring them
> to edit all of their queries in order to enable the old behavior would
> become an upgrade barrier.
>

+100

This could be a very bad, almost impossible to catch, behaviour break. 
Even if we add the GUC, we're probably going to be imposing very 
significant code audit costs on some users.

cheers

andrew