Horton

Re: Flushing large data immediately in pqcomm

Melih Mutlu <m.melihmutlu@gmail.com>

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From: Melih Mutlu <m.melihmutlu@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, David Rowley <dgrowleyml@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Jelte Fennema-Nio <postgres@jeltef.nl>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Thomas Munro <thomas.munro@gmail.com>
Date: 2024-03-28T19:47:24Z
Lists: pgsql-hackers 
On Wed, Mar 27, 2024 at 18:54 Robert Haas <robertmhaas@gmail.com> wrote:

> On Wed, Mar 27, 2024 at 7:39 AM David Rowley <dgrowleyml@gmail.com> wrote:
> > Robert, I understand you'd like a bit more from this patch. I'm
> > wondering if you planning on blocking another committer from going
> > ahead with this? Or if you have a reason why the current state of the
> > patch is not a meaningful enough improvement that would justify
> > possibly not getting any improvements in this area for PG17?
>
> So, I think that the first version of the patch, when it got a big
> chunk of data, would just flush whatever was already in the buffer and
> then send the rest without copying.


Correct.

The current version, as I
> understand it, only does that if the buffer is empty; otherwise, it
> copies data as much data as it can into the partially-filled buffer.


Yes, currently it should fill and flush the buffer first, if it’s not
already empty. Only then it sends the rest without copying.

Thanks,
Melih

Commits

  1. Avoid needless large memcpys in libpq socket writing