Re: First draft of the PG 15 release notes

On Wed, May 11, 2022 at 02:31:08PM +1200, David Rowley wrote:
> On Wed, 11 May 2022 at 14:02, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> >
> > On Wed, May 11, 2022 at 12:39:41PM +1200, David Rowley wrote:
> > > I think the sort improvements done in v15 are worth a mention under
> > > General Performance. The commits for this were 91e9e89dc, 40af10b57
> > > and 697492434. I've been running a few benchmarks between v14 and v15
> > > over the past few days and a fairly average case speedup is about 25%.
> > > but there are cases where I've seen up to 400%. I think the increase
> > > is to an extent that we maybe should have considered making tweaks in
> > > cost_tuplesort(). I saw some plans that ran in about 60% of the time
> > > by disabling Hash Agg and allowing Sort / Group Agg to do the work.
> >
> > Good point. Do you have any suggested text? I can't really see it
> > clearly based on the commits, except "sorting is faster".
>
> If we're going to lump those into a single line then maybe something
> along the lines of:
>
> * Reduce memory consumption and improve performance of sorting tuples in memory
>
> I think one line is fine from a user's perspective, but it's slightly
> harder to know the order of the names in the credits given the 3
> independent commits.

Okay, I went with this:

<!--
Author: David Rowley <drowley(at)postgresql(dot)org>
2021-07-22 [91e9e89dc] Make nodeSort.c use Datum sorts for single column sorts
Author: David Rowley <drowley(at)postgresql(dot)org>
2022-04-04 [40af10b57] Use Generation memory contexts to store tuples in sorts
Author: John Naylor <john(dot)naylor(at)postgresql(dot)org>
2022-04-02 [697492434] Specialize tuplesort routines for different kinds of abb
-->

<listitem>
<para>
Improve performance and reduce memory consumption of in-memory
sorts (Ronan Dunklau, David Rowley, Thomas Munro)
</para>
</listitem>

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

Indecision is a decision. Inaction is an action. Mark Batterson