Re: Should we add GUCs to allow partition pruning to be disabled?

On Wed, Apr 18, 2018 at 12:07:18PM +1200, David Rowley wrote:
> In PG10 the planner's partition pruning could be disabled by changing
> the constraint_exclusion GUC to off.  This is still the case for PG11,
> but only for UPDATE and DELETE queries. There is currently no way to
> disable partition pruning for SELECT.
>
> Should we allow this?

> 3. No new GUCs / Do nothing.

Maybe this is divergent from the details of the implementation; but, from a
user's perspective: why not continue to use constraint_exclusion?

I would suggest to add zero new GUCs:

0. constraint_exclusion={off,partition,on,PLANNER*,EXECUTOR*}