On Thu, Jul 31, 2025 at 5:25 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Cool, will you do the legwork?
I'll give it a go.
> > Is there a convenient choke point for this in the planner?
>
> I'd be inclined to do it as late as possible, in create_plan
> (so that we don't expend the effort if we don't choose that
> index path). So in or near fix_indexqual_references is
> probably a good spot.
Understood.
> >> An alternative thought is that maybe the run-time sort is expensive
> >> enough that the planner ought to account for it in its estimates.
>
> > I tend to doubt that this will ever make much sense.
>
> As you say, getting the cost estimates accurate enough is daunting,
> which is why I called it a research project.
I think that it might make sense to add a little more startup cost to
plans with SAOP arrays. But that doesn't seem likely to help with this
particular problem.
--
Peter Geoghegan
