From: Bruce Momjian <bruce@momjian.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Thomas Munro <thomas.munro@gmail.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Cc: Stephen Frost <sfrost@snowman.net>
Subject: Re: Append with naive multiplexing of FDWs
Date: Mon, 9 Dec 2019 12:18:44 -0500
Message-ID: <20191209171844.GA5192@momjian.us> (raw)
In-Reply-To: <CA+TgmoZc6HXhGJ+JSQ6ekcZT4Co-MhDH08wxVy3f9Dtt1TuOrg@mail.gmail.com>
References: <20190927162002.GC31412@momjian.us>
<CA+hUKGKV5iYxw9jkSWQ769SGpgQ+GM34T=AiMdVW4yfXdmc8yA@mail.gmail.com>
<20191130192611.GB4326@momjian.us>
<20191205.122637.1855053671071685153.horikyota.ntt@gmail.com>
<CA+hUKGKHGLgUuUsC15Wdm3eCkDq7+eHPE9zKaVEvygyU7LdJNA@mail.gmail.com>
<20191205181217.GA12895@momjian.us>
<CA+TgmoZc6HXhGJ+JSQ6ekcZT4Co-MhDH08wxVy3f9Dtt1TuOrg@mail.gmail.com>
On Thu, Dec 5, 2019 at 03:19:50PM -0500, Robert Haas wrote:
> On Thu, Dec 5, 2019 at 1:12 PM Bruce Momjian <bruce@momjian.us> wrote:
> > I agree with Stephen's request. We have been waiting for the executor
> > rewrite for a while, so let's just do something simple and see how it
> > performs.
>
> I'm sympathetic to the frustration here, and I think it would be great
> if we could find a way forward that doesn't involve waiting for a full
> rewrite of the executor. However, I seem to remember that when we
> tested the various patches that various people had written for this
> feature (I wrote one, too) they all had a noticeable performance
> penalty in the case of a plain old Append that involved no FDWs and
> nothing asynchronous. I don't think it's OK to have, say, a 2%
> regression on every query that involves an Append, because especially
> now that we have partitioning, that's a lot of queries.
>
> I don't know whether this patch has that kind of problem. If it
> doesn't, I would consider that a promising sign.
Certainly any overhead on normal queries would be unacceptable.
--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ As you are, so once was I. As I am, so you will be. +
+ Ancient Roman grave inscription +
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To: pgsql-hackers@postgresql.org
Cc: bruce@momjian.us, robertmhaas@gmail.com, thomas.munro@gmail.com, horikyota.ntt@gmail.com, sfrost@snowman.net
Subject: Re: Append with naive multiplexing of FDWs
In-Reply-To: <20191209171844.GA5192@momjian.us>
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