Feedback-ID: id4a34324:Fastmail
Date: Thu, 8 Jun 2023 11:54:44 -0700
From: Andres Freund <andres@anarazel.de>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Hannu Krosing <hannuk@google.com>,
	Matthias van de Meent <boekewurm+postgres@gmail.com>,
	"Jonathan S. Katz" <jkatz@postgresql.org>,
	Heikki Linnakangas <hlinnaka@iki.fi>, Tom Lane <tgl@sss.pgh.pa.us>,
	pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Let's make PostgreSQL multi-threaded
Message-ID: <20230608185444.yujqs3ybgjqetoku@awork3.anarazel.de>
References: <4178104.1685978307@sss.pgh.pa.us>
 <4ce6c0f8-e8a4-1672-93fd-49d3fa975ee5@iki.fi>
 <cd27db0c-01ae-ba4d-f141-8712cbb4188c@postgresql.org>
 <20230607213721.al3etgcgtija3ytz@awork3.anarazel.de>
 <CAMT0RQTAFrx5xVJ9SXyjP71=SmU+U9+4dDm+XEZWWoy6pbCF5g@mail.gmail.com>
 <CAEze2Whojjh++1Ybw8ohxo46DPeDS4aD5dkPsOse4Q-8r56awQ@mail.gmail.com>
 <CAMT0RQSfoUCNskuweVBhmEiWh76q+eqDhX+5_bWpq8Qq-KuTTg@mail.gmail.com>
 <CA+TgmoZhySzy4QuupAMCi3Fs7ZDwwKkUE9VEgxF2nn71Bo-FXQ@mail.gmail.com>
 <CAMT0RQTCFec0J4hQDcpC0CZ4F-7VWFZXpREgaRU-96bVQ1pj2Q@mail.gmail.com>
 <CA+TgmobtDMH6Pzioyw5PXA_z2Nq8whzXY57O=Q_J=kHDY-eZcw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <CA+TgmobtDMH6Pzioyw5PXA_z2Nq8whzXY57O=Q_J=kHDY-eZcw@mail.gmail.com>
Archived-At: <https://www.postgresql.org/message-id/20230608185444.yujqs3ybgjqetoku%40awork3.anarazel.de>
Precedence: bulk

Hi,

On 2023-06-08 11:56:13 -0400, Robert Haas wrote:
> On Thu, Jun 8, 2023 at 11:02 AM Hannu Krosing <hannuk@google.com> wrote:
> > No, I meant that this needs to be fixed at OS level, by being able to
> > use the same mapping.
> >
> > We should not shy away from asking the OS people for adding the useful
> > features still missing.
> >
> > It was mentioned in the Unconference Kernel Hacker AMA talk and said
> > kernel hacker works for Oracle, andf they also seemed to be needing
> > this :)
> 
> Fair enough, but we aspire to work on a bunch of different operating
> systems. To make use of an OS facility, we need something that works
> on at least Linux, Windows, macOS, and a few different BSD flavors.
> It's not as if when the PostgreSQL project asks for a new operating
> system facility everyone springs into action to provide it
> immediately. And even if they did, and even if they all released an
> implementation of whatever we requested next year, it would still be
> at least five, more realistically ten, years before systems with those
> facilities were ubiquitous.

I'm less concerned about this aspect - most won't have upgraded to a version
of postgres that benefit from threaded postgres in a similar timeframe. And if
the benefits are large enough, people will move.  But:


> And unless we have truly obscene amounts of clout in the OS community, it's
> likely that all of those different operating systems would implement
> different things to meet the stated need, and then we'd have to have a
> complex bunch of platform-dependent code in order to keep working on all of
> those systems.

And even more likely, they just won't do anything, because it's a model that
large parts of the industry have decided isn't going anywhere. It'd be one
thing if we had 5 kernel devs that we could deploy to work on this, but we
don't. So we have to convince kernel devs employed by others that somehow this
is an urgent enough thing that they should work on it. The likely, imo
justified, answer is just going to be: Fix your architecture, then we can
talk.

Greetings,

Andres Freund