Re: Flushing large data immediately in pqcomm - Mailing list pgsql-hackers

From Jelte Fennema-Nio
Subject Re: Flushing large data immediately in pqcomm
Date
Msg-id CAGECzQQMktuTj8ijJgBRXCwLEqfJyAFxg1h7rCTej-6=cR0r=Q@mail.gmail.com
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In response to Re: Flushing large data immediately in pqcomm  (Melih Mutlu <m.melihmutlu@gmail.com>)
List pgsql-hackers
On Thu, 14 Mar 2024 at 12:22, Melih Mutlu <m.melihmutlu@gmail.com> wrote:
> I did some experiments with this patch, after previous discussions

One thing I noticed is that the buffer sizes don't seem to matter much
in your experiments, even though Andres his expectation was that 1400
would be better. I think I know the reason for that:

afaict from your test.sh script you connect psql over localhost or
maybe even unix socket to postgres. Neither of those would not have an
MTU of 1500. You'd probably want to do those tests over an actual
network or at least change the MTU of the loopback interface. e.g. my
"lo" interface mtu is 65536 by default:

❯ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever



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