Re: [PATCH] Incremental sort (was: PoC: Partial sort)

From: James Coleman <jtc331(at)gmail(dot)com>
To: Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Michael Paquier <michael(at)paquier(dot)xyz>, Rafia Sabih <rafia(dot)pghackers(at)gmail(dot)com>, Peter Geoghegan <pg(at)bowt(dot)ie>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Shaun Thomas <shaun(dot)thomas(at)2ndquadrant(dot)com>, Dmitry Dolgov <9erthalion6(at)gmail(dot)com>, Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru>, PostgreSQL Developers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Andreas Karlsson <andreas(at)proxel(dot)se>
Subject: Re: [PATCH] Incremental sort (was: PoC: Partial sort)
Date: 2020-04-03 01:40:45
Message-ID: CAAaqYe9XO7ZKrpVkrz2e0ja=eeFCX0Wqpmc7r23R84JU9uCLxQ@mail.gmail.com
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On Thu, Apr 2, 2020 at 8:46 PM James Coleman <jtc331(at)gmail(dot)com> wrote:
>
> On Thu, Apr 2, 2020 at 8:20 PM Tomas Vondra
> <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> > ...
> > 5) Overall, I think the costing is OK. I'm sure we'll find cases that
> > will need improvements, but that's fine. However, we now have
> >
> > - cost_tuplesort (used to be cost_sort)
> > - cost_full_sort
> > - cost_incremental_sort
> > - cost_sort
> >
> > I find it a bit confusing that we have cost_sort and cost_full_sort. Why
> > don't we just keep using the dummy path in label_sort_with_costsize?
> > That seems to be the only external caller outside costsize.c. Then we
> > could either make cost_full_sort static or get rid of it entirely.
>
> This another area of the patch I haven't really modified.

See attached for a cleanup of this; it removed cost_fullsort so
label_sort_with_costsize is back to how it was.

I've directly merged this into the patch series; if you'd like to see
the diff I can send that along.

James

Attachment Content-Type Size
v53-0001-Consider-low-startup-cost-when-adding-partial-pa.patch text/x-patch 4.6 KB
v53-0003-Consider-incremental-sort-paths-in-additional-pl.patch text/x-patch 25.9 KB
v53-0002-Implement-incremental-sort.patch text/x-patch 170.2 KB

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