Re: First draft of the PG 15 release notes

On Wed, May 11, 2022 at 12:39:41PM +1200, David Rowley wrote:
> On Wed, 11 May 2022 at 03:44, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> >
> > I have completed the first draft of the PG 15 release notes and you can
> > see the results here:
> >
> > https://momjian.us/pgsql_docs/release-15.html
>
> Thanks for doing that tedious work.
>
> 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".

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

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