Re: First draft of the PG 15 release notes - Mailing list pgsql-hackers

From David Rowley
Subject Re: First draft of the PG 15 release notes
Date
Msg-id CAApHDvo57tuCk=L_=_Q0mvmBxUYi+aoZZ6HtxmYM9cg7euX_KA@mail.gmail.com
Whole thread Raw
In response to Re: First draft of the PG 15 release notes  (Bruce Momjian <bruce@momjian.us>)
Responses Re: First draft of the PG 15 release notes
Re: First draft of the PG 15 release notes
List pgsql-hackers
On Wed, 11 May 2022 at 14:02, Bruce Momjian <bruce@momjian.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.

David



pgsql-hackers by date:

Previous
From: Michael Paquier
Date:
Subject: Re: make MaxBackends available in _PG_init
Next
From: "osumi.takamichi@fujitsu.com"
Date:
Subject: RE: Data is copied twice when specifying both child and parent table in publication