Date: Thu, 29 May 2025 12:41:17 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Melanie Plageman <melanieplageman@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@lists.postgresql.org>
Subject: Re: PG 18 release notes draft committed
Message-ID: <aDiOLT28-e0qpKWp@momjian.us>
References: <aBQxop9YxQDad8-W@momjian.us>
 <CAAKRu_YsVvyantS0X0Y_-vp_97=yGaoYJMXXyCEkR7pumAH3Jg@mail.gmail.com>
 <aDfLS_8fBdT0qbQn@momjian.us>
 <CAAKRu_bqjgSYA+OdemL-X91Yv53OwsVARZy+-tRyj8YQ=kcj0A@mail.gmail.com>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="n8NTxVJnFRypvY8a"
Content-Disposition: inline
In-Reply-To: 
 <CAAKRu_bqjgSYA+OdemL-X91Yv53OwsVARZy+-tRyj8YQ=kcj0A@mail.gmail.com>
Archived-At: 
 <https://www.postgresql.org/message-id/aDiOLT28-e0qpKWp%40momjian.us>
Precedence: bulk


--n8NTxVJnFRypvY8a
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Thu, May 29, 2025 at 09:42:30AM -0400, Melanie Plageman wrote:
> > > "Add an asynchronous I/O subsystem"
> > >
> > > I notice we don't call out any of the operations where users could
> > > expect to see asynchronous IO be used. Some were enabled in 17 (like
> > > sequential scans, analyze, and pg_prewarm), but most of the read
> > > stream users went in this release:
> > >
> > > d9c7911e1a5, 043799fa08c, e215166c9c8, 69273b818b1, c5c239e26e3,
> > > 2b73a8cd33b, 9256822608f, c3e775e608f, 8720a15e9ab12, 65c310b310a
> > >
> > > I have had users ask me already which operations they can expect to
> > > use asynchronous I/O. The most commonly encountered AIO operations are
> > > probably be vacuum, bitmap heap scan, and sequential scans, but it
> > > might be worth having a list somewhere of what uses AIO. I expect
> > > we'll get the question quite often.
> >
> > Yes, I knew I needed more detail on this.  I have added text in this
> > commit to try to improve that.
> 
> Maybe it is worth saying something at the end like "amongst other
> operations" to clarify it isn't just those.

I am not a fan of "etc." but in this case it makes sense, so added it in
the attached, applied patch.

> I noticed in the PG 17 release notes [1] we did include the shas of
> each of the commits for the read stream users. Should we do that here
> as well? Those are what enable those operations to use AIO.

So, I added the read stream item to PG 17 since that was a new
infrastructure feature, but for PG 18, we are just improving that
internal infrastructure, so didn't mention it.  If you think we should
add those commits, I can do it.

-- 
  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.

--n8NTxVJnFRypvY8a
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment; filename="master.diff"

diff --git a/doc/src/sgml/release-18.sgml b/doc/src/sgml/release-18.sgml
index 718f7b20bf1..3315ea52def 100644
--- a/doc/src/sgml/release-18.sgml
+++ b/doc/src/sgml/release-18.sgml
@@ -569,7 +569,7 @@ Add an asynchronous I/O subsystem (Andres Freund, Thomas Munro, Nazir Bilal Yavu
 </para>
 
 <para>
-This feature allows backends to queue multiple read requests, which allows for more efficient sequential scans, bitmap heap scans, and vacuums.
+This feature allows backends to queue multiple read requests, which allows for more efficient sequential scans, bitmap heap scans, vacuums, etc.
 This is enabled by server variable io_method, with server variables io_combine_limit and io_max_combine_limit added to control it.  This also enables
 effective_io_concurrency and maintenance_io_concurrency values greater than zero for systems without fadvise() support.  The new system view pg_aios shows the file handles being used
 for asynchronous I/O.

--n8NTxVJnFRypvY8a--