From: | Rob Brown-Bayliss <r(dot)brown(dot)bayliss(at)gmail(dot)com> |
---|---|
To: | John R Pierce <pierce(at)hogranch(dot)com> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Libpq is very slow on windows but fast on linux. |
Date: | 2010-11-07 01:13:47 |
Message-ID: | AANLkTinRCEzpXoBgqep6qC8i9AqwSRmTztpoKefnN70n@mail.gmail.com |
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Thread: | |
Lists: | pgsql-general |
Ok, So I did that, in the windows capture file are many many lines of
Red text on a black background, I assume thats a bad thing. It's
every second or third line vs just a handful on the linux capture.
Most of these lines are like:
postgresql [ACK] Seq=5429 Ack=##### Win=65700 Len=0
Where the ACK number is always different.
As I said before I really don't know what I am looking at.
On Sun, Nov 7, 2010 at 1:19 PM, John R Pierce <pierce(at)hogranch(dot)com> wrote:
> On 11/06/10 5:12 PM, Rob Brown-Bayliss wrote:
>>
>> On Sun, Nov 7, 2010 at 1:06 PM, John R Pierce<pierce(at)hogranch(dot)com> wrote:
>>>
>>> I think I'd run a packet sniffer like Wireshark on both client platforms,
>>> sniffing 5432/tcp and see if there's something unusual in the timing of
>>> the
>>> packets, incorrect MTU or something, lost packets and extra retries, or
>>> whatever. Perhaps Windows isn't using a sufficiently large TCP Recieve
>>> Window (RWIN) value, or something.
>>
>> I am a bit out of my depth there, but for all other network use the
>> machine seems the same in either os. That is no noticiable difference
>> in download/upload speed.
>
> download/uploads from/to this same server in Canada ?
>
> Wireshark is pretty easy to use. tell it you only want to capture TCP
> traffic on port 5432 (to or from 5432), then start its capture and run your
> query. it shows the network packets with a ton of info including a
> millisecond accurate timestamp on each packet. do this on each OS and
> compare the timings on these captures (you can save the capture from one
> system and load it on wireshark on the other OS so you can do side by side
> compares)
>
> studying the details of a TCP connection via Wireshark should lead to a good
> deal of understanding of the underpinnings of TCP/IP networking.
>
>
>
>
>
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--
--
Rob
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