Horton

Re: First draft of the PG 15 release notes

Bruce Momjian <bruce@momjian.us>

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From: Bruce Momjian <bruce@momjian.us>
To: David Rowley <dgrowleyml@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2022-05-11T14:32:21Z
Lists: pgsql-hackers 
On Wed, May 11, 2022 at 02:31:08PM +1200, David Rowley wrote:
> 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.

Okay, I went with this:

	<!--
	Author: David Rowley <drowley@postgresql.org>
	2021-07-22 [91e9e89dc] Make nodeSort.c use Datum sorts for single column sorts
	Author: David Rowley <drowley@postgresql.org>
	2022-04-04 [40af10b57] Use Generation memory contexts to store tuples in sorts
	Author: John Naylor <john.naylor@postgresql.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@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

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

Commits

  1. Doc: last minute adjustment to the release notes

  2. Doc: more tweaking of v15 release notes.

  3. Doc: further adjust notes about pg_upgrade_output.d.

  4. Doc: add list of major features to the v15 release notes.

  5. relnotes: update item about public schema permission change

  6. relnotes: update ordered partition scan item

  7. relnotes: add Heikki to UTF8 item

  8. relnotes: improve UTF8 text item in relation to ASCII

  9. relnotes: add null logical replication item

  10. relnotes: adjust several logical replication items and FK text

  11. relnotes: mention non-exclusive backup mode was deprecated

  12. relnotes: add author to in-memory sorts item

  13. relnotes: update for non-exclusive backup mode removal

  14. relnote: improve sorting entries

  15. relnotes: adjustments from Álvaro Herrera

  16. relnotes: update foreign key partition and add sort items

  17. relnotes: more adjustments

  18. relnotes: logical replication permissions checked by subscrib.

  19. relnotes: adjustments

  20. relnotes: remove sequence replication and update 'postgres -C'

  21. relnote: extensive updates

  22. relnotes: "training" -> "trailing"

  23. Standardize references to Zstandard as <productname>

  24. pgstat: Update docs to match the shared memory stats reality.

  25. Raise a WARNING for missing publications.

  26. Skip empty transactions for logical replication.

  27. Optionally disable subscriptions on error.

  28. Allow root-owned SSL private keys in libpq, not only the backend.

  29. Use COPY FREEZE in pgbench for faster benchmark table population.