Re: [PATCH] Use optimized single-datum tuplesort in ExecSort

On Thu, Jul 15, 2021 at 11:45 PM David Rowley <dgrowleyml(at)gmail(dot)com> wrote:
>
> On Fri, 16 Jul 2021 at 02:53, Ronan Dunklau <ronan(dot)dunklau(at)aiven(dot)io> wrote:
> > Please find attached a v9 just moving the flag setting to ExecInitSort, and my
> > apologies if I misunderstood your point.
>
> I took this and adjusted a few things and ended up with the attached patch.
>
> The changes are fairly minor. I made the bracing consistent between
> both tuplesort_begin calls. I rewrote the comment at the top of
> ExecSort() to make it more clear about each method used.
>
> I also adjusted the comment down at the end of ExecSort that was
> mentioning something about tuplesort_gettupleslot returning NULL.
> Your patch didn't touch this, but to me, the comment just looked wrong
> both before and after the changes. tuplesort_gettupleslot returns
> false and sets the slot to empty when it runs out of tuples. Anyway,
> I wrote something there that I think improves that.
>
> I feel like this patch is commit-worthy now. However, I'll leave it
> for a few days, maybe until after the weekend as there's been a fair
> bit of interest and I imagine someone will have comments to make.

The only remaining question I have is whether or not costing needs to
change, given the very significant speedup for datum sort.

James