Re: Low throughput of binary inserts from windows to linux - Mailing list pgsql-performance

From Tom Lane
Subject Re: Low throughput of binary inserts from windows to linux
Date
Msg-id 4101.1165941200@sss.pgh.pa.us
Whole thread Raw
In response to Re: Low throughput of binary inserts from windows to linux  ("Axel Waggershauser" <awagger@web.de>)
Responses Re: Low throughput of binary inserts from windows to linux
List pgsql-performance
"Axel Waggershauser" <awagger@web.de> writes:
> On 12/12/06, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I think this almost certainly indicates a Nagle/delayed-ACK
>> interaction.  I googled and found a nice description of the issue:
>> http://www.stuartcheshire.org/papers/NagleDelayedAck/

> In case I was mistaken, this explanation makes perfectly sens to me.
> But then again it would indicate a 'bug' in libpq, in the sense that
> it (apparently) sets TCP_NODELAY on linux but not on windows.

No, it would mean a bug in Windows in that it fails to honor TCP_NODELAY.
Again, given that you only see the behavior at one specific message
length, I suspect this is a corner case rather than a generic "it
doesn't work" issue.

We're pretty much guessing though.  Have you tried tracing the traffic
with a packet sniffer to see what's really happening at different
message sizes?

            regards, tom lane

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