Date: Sun, 19 Apr 2026 13:53:08 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Andres Freund <andres@anarazel.de>
Cc: David Geier <geidav.pg@gmail.com>,
	PostgreSQL-development <pgsql-hackers@lists.postgresql.org>
Subject: Re: First draft of PG 19 release notes
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On Sun, Apr 19, 2026 at 11:10:40AM -0400, Andres Freund wrote:
> Hi,
> 
> On 2026-04-19 09:32:45 -0400, Bruce Momjian wrote:
> > On Sun, Apr 19, 2026 at 01:27:10PM +0200, David Geier wrote:
> > > >>> So, it seems there is no user-visible change, except it is faster.  Does
> > > >>> it enable new workloads?  A 3x speedup probably does.  Should this be a
> > > >>> pg_trgm item, with a description mentioning GIN in general, or should it
> > > >>> be a GIN item, perhaps mentioning pg_trgm?  Do you have any suggested
> > > >>> text and list of commits?
> > > >>
> > > >> Not all patches from the initial mail have been committed yet. Hence,
> > > >> currently the speed up is less. However, once they got all committed
> > > >> they would indeed open up new "use cases". For example, I know users
> > > >> that don't add GIN indexes to very large tables because creating them
> > > >> takes too long.
> > > > 
> > > > Yes, GIN index creation has always been considered slow, so it is good
> > > > it is being worked on.  I wonder if we should just wait for it all to be
> > > > committed before adding it to the release notes, unless you want to
> > > > measure the improvement we have in PG 19.
> > > 
> > > I've measured with the same benchmark I used in the original thread [1].
> > > With latest master the results are as follows:
> > > 
> > > Dataset  | REL_18_3   | master     | Speedup
> > > ---------|------------|------------|--------
> > > movies   |  10,561 ms |   9,124 ms | 1.17x
> > > lineitem | 263,523 ms | 234,605 ms | 1.12x
> > > 
> > > That's because three patches from the patchset haven't been committed
> > > yet. Two of the three patches are the most impactful from the patchset.
> > 
> > Okay, at +12-17%, so we should wait until all the patches are in to
> > mention this.  Thanks.
> 
> That makes no sense to me.  It's a material improvement that could convince
> people to upgrade.  Why would you not want to mention that, just because PG 20
> might have further improvements? There *always* will be further potential
> improvements.

The text I put in the wiki, which I have followed for years, says:

	https://wiki.postgresql.org/wiki/Creating_Major_Release_Notes
	Performance improvements are mentioned in the release notes if
	they are user-visible (e.g., new syntax) or significant enough
	to enable new workloads.

I didn't think +12-17% for an index build would enable new workloads. 
If you want to relitigate that, you are welcome to do so.  If this is
changed, it has to be done so consistently, not just for this item.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Do not let urgent matters crowd out time for investment in the future.