From: Axel Waggershauser <awagger@web.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-performance@postgresql.org
Subject: Re: Low throughput of binary inserts from windows to linux
Date: Mon, 11 Dec 2006 23:44:25 +0100
Message-ID: <5e66c6e90612111444y78729a71m4ec9852ae9bc8567@mail.gmail.com> (raw)
In-Reply-To: <12645.1165852740@sss.pgh.pa.us>
References: <5e66c6e90612080417r23ecaea4p210905f868c26c7f@mail.gmail.com>
<5e66c6e90612081724m57293ffdy21d6b45697e69bd4@mail.gmail.com>
<3317.1165636358@sss.pgh.pa.us>
<5e66c6e90612110658r3c0918f6v4fd3682363db5c15@mail.gmail.com>
<12645.1165852740@sss.pgh.pa.us>
On 12/11/06, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Yeah, that's what I couldn't think of the other day. The principal
> report was here:
> http://archives.postgresql.org/pgsql-general/2005-01/msg01231.php
>
> By default, Windows XP installs the QoS Packet Scheduler service.
> It is not installed by default on Windows 2000. After I installed
> QoS Packet Scheduler on the Windows 2000 machine, the latency
> problem vanished.
I found a QoS-RVPS service (not sure about the last four characters
and I'm sitting at my mac at home now...) on one of the WinXP test
boxes, started it and immediately lost network connection :-(. Since I
have pretty much the same skepticism regarding the usefulness of a QoS
packet scheduler to help with a raw-throughput-problem like Lincoln
Yeoh in a follow up mail to the above
(http://archives.postgresql.org/pgsql-general/2005-01/msg01243.php), I
didn't investigate this further.
And regarding the TCP_NODELAY hint from Kevin Grittner: if I am not
wrong with interpreting fe_connect.c, the libpq already deals with it
(fe_connect.c:connectNoDelay). But this made me think about the
'page'-size I use in my blob table...
I tested different sizes on linux some time ago and found that 64KB
was optimal. But playing with different sizes again revealed that my
windows->linux problem seems to be solved if I use _any_ other
(reasonable - meaning something between 4K and 512K) power of two ?!?
Does this make sense to anyone?
Thanks,
axel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: awagger@web.de, tgl@sss.pgh.pa.us
Subject: Re: Low throughput of binary inserts from windows to linux
In-Reply-To: <5e66c6e90612111444y78729a71m4ec9852ae9bc8567@mail.gmail.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox