I wrote:
> Kyotaro HORIGUCHI wrote:
> > Another is, you changed pathkeys expantion to be all-or-nothing
decision.
> > While this change should simplify the code slightly, it also dismisses
> > the oppotunity for partially-extended pathkeys. Could you let me know
> > the
> reason
> > why you did so.
> At first I thought the partially-extended pathkey list that is made from
> query_pathkeys, as you proposed in the original versions of the patch.
But
> I've started to doubt whether it's worth doing that because I think the
> partially-extended pathkey list is merely one example while the original
> pathkey list can be partially-extended in different ways, ie, ISTM the
> partially-extended pathkey list doesn't necessarily have the optimality
> in anything significant. We might be able to partially-extend the
original
> pathkey list optimally in something significant, but that seems useless
> complexity to me. So, I modified the patch to do the all-or-nothing
> decision.
Here I mean the optimality for use in merge joins.
Thanks,
Best regards,
Etsuro Fujita