Re: Append with naive multiplexing of FDWs - Mailing list pgsql-hackers

From Robert Haas
Subject Re: Append with naive multiplexing of FDWs
Date
Msg-id CA+TgmoZc6HXhGJ+JSQ6ekcZT4Co-MhDH08wxVy3f9Dtt1TuOrg@mail.gmail.com
Whole thread Raw
In response to Re: Append with naive multiplexing of FDWs  (Bruce Momjian <bruce@momjian.us>)
Responses Re: Append with naive multiplexing of FDWs  (Thomas Munro <thomas.munro@gmail.com>)
Re: Append with naive multiplexing of FDWs  (Bruce Momjian <bruce@momjian.us>)
List pgsql-hackers
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.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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