Message-ID: <16a3acca-4dd2-cbcd-d078-1e01802a0b74@joeconway.com>
Date: Mon, 5 Jun 2023 16:08:24 -0400
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.11.0
Subject: Re: Let's make PostgreSQL multi-threaded
Content-Language: en-US
To: Andrew Dunstan <andrew@dunslane.net>, Tom Lane <tgl@sss.pgh.pa.us>,
 Heikki Linnakangas <hlinnaka@iki.fi>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
References: <31cc6df9-53fe-3cd9-af5b-ac0d801163f4@iki.fi>
 <4178104.1685978307@sss.pgh.pa.us>
 <31ec84ad-c10c-9351-bf9f-19679c832b73@dunslane.net>
From: Joe Conway <mail@joeconway.com>
In-Reply-To: <31ec84ad-c10c-9351-bf9f-19679c832b73@dunslane.net>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Archived-At: <https://www.postgresql.org/message-id/16a3acca-4dd2-cbcd-d078-1e01802a0b74%40joeconway.com>
Precedence: bulk

On 6/5/23 14:51, Andrew Dunstan wrote:
> 
> On 2023-06-05 Mo 11:18, Tom Lane wrote:
>> Heikki Linnakangas<hlinnaka@iki.fi>  writes:
>>> I spoke with some folks at PGCon about making PostgreSQL multi-threaded,
>>> so that the whole server runs in a single process, with multiple
>>> threads. It has been discussed many times in the past, last thread on
>>> pgsql-hackers was back in 2017 when Konstantin made some experiments [0].
>>> I feel that there is now pretty strong consensus that it would be a good
>>> thing, more so than before. Lots of work to get there, and lots of
>>> details to be hashed out, but no objections to the idea at a high level.
>>> The purpose of this email is to make that silent consensus explicit. If
>>> you have objections to switching from the current multi-process
>>> architecture to a single-process, multi-threaded architecture, please
>>> speak up.
>> For the record, I think this will be a disaster.  There is far too much
>> code that will get broken, largely silently, and much of it is not
>> under our control.
> 
> If we were starting out today we would probably choose a threaded 
> implementation. But moving to threaded now seems to me like a 
> multi-year-multi-person project with the prospect of years to come 
> chasing bugs and the prospect of fairly modest advantages. The risk to 
> reward doesn't look great.
> 
> That's my initial reaction. I could be convinced otherwise.


I read through the thread thus far, and Andrew's response is the one 
that best aligns with my reaction.


-- 
Joe Conway
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com