Horton

Re: Flushing large data immediately in pqcomm

Jelte Fennema-Nio <postgres@jeltef.nl>

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From: Jelte Fennema-Nio <postgres@jeltef.nl>
To: Melih Mutlu <m.melihmutlu@gmail.com>
Cc: David Rowley <dgrowleyml@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Heikki Linnakangas <hlinnaka@iki.fi>, Thomas Munro <thomas.munro@gmail.com>
Date: 2024-03-21T09:58:40Z
Lists: pgsql-hackers 
On Thu, 21 Mar 2024 at 01:24, Melih Mutlu <m.melihmutlu@gmail.com> wrote:
> What if I do a simple comparison like PqSendStart == PqSendPointer instead of calling pq_is_send_pending()

Yeah, that sounds worth trying out. So the new suggestions to fix the
perf issues on small message sizes would be:

1. add "inline" to internal_flush function
2. replace pq_is_send_pending() with PqSendStart == PqSendPointer
3. (optional) swap the order of PqSendStart == PqSendPointer and len
>= PqSendBufferSize

Commits

  1. Avoid needless large memcpys in libpq socket writing