Re: Strange result: UNIX vs. TCP/IP sockets

От: The Hermit Hacker
Тема: Re: Strange result: UNIX vs. TCP/IP sockets
Дата: ,
Msg-id: 20030704143143.U45926@hub.org
(см: обсуждение, исходный текст)
Ответ на: Strange result: UNIX vs. TCP/IP sockets  (Andrew Sullivan)
Ответы: Re: Strange result: UNIX vs. TCP/IP sockets  (Vincent van Leeuwen)
Список: pgsql-performance

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Strange result: UNIX vs. TCP/IP sockets  (Andrew Sullivan, )
 Re: Strange result: UNIX vs. TCP/IP sockets  (The Hermit Hacker, )
  Re: Strange result: UNIX vs. TCP/IP sockets  (Vincent van Leeuwen, )
   Re: Strange result: UNIX vs. TCP/IP sockets  (Andrew Sullivan, )
    Re: Strange result: UNIX vs. TCP/IP sockets  (Tom Lane, )
     Re: Strange result: UNIX vs. TCP/IP sockets  (Andrew Sullivan, )
 Re: Strange result: UNIX vs. TCP/IP sockets  (Rod Taylor, )
 Re: Strange result: UNIX vs. TCP/IP sockets  (Andrew Sullivan, )

'K, this is based on "old information", I don't know if Sun changed it
'yet again' ... but, when I was working at the University, one of our IT
directors gave me a report that deal with something Sun did (god, I'm so
detailed  here, eh?) to "mimic" how Microsoft broke the TCP/IP protocol
... the report was in relation to Web services, and how the change
actually made Sun/Solaris appear to be slower then Microsoft ...

And Sun made this the 'default' setting, but it was disablable in
/etc/systems ...

Sorry for being so vague, but if I recall correctly, it had something to
do with adding an extra ACK to each packet ... maybe even as vague as the
above is, it will jar a memory for someone else?


On Fri, 4 Jul 2003, Andrew Sullivan wrote:

> Hi all,
>
> We're run into a rather odd problem here, and we're puzzling out
> what's going on.  But while we do, I thought I'd see if anyone else
> has anything similar to report.
>
> This is for 7.2.4 on Solaris 8.
>
> We have a query for which EXPLAIN ANALYSE on a local psql connection
> always returns a time of between about 325 msec and 850 msec
> (depending on other load, whether the result is in cache, &c. -- this
> is an aggregates query involving min() and count()).
>
> If I connect using -h 127.0.0.1, however, I can _sometimes_ get the
> query to take as long as 1200 msec.  The effect is sporadic (of
> course.  If it were totally predictable, the computing gods wouldn't
> be having any fun with me), but it is certainly there off and on.
> (We discovered it because our application is regularly reporting
> times on this query roughly twice as long as I was able to get with
> psql, until I connected via TCP/IP.)
>
> I'll have more to report as we investigate further -- at the moment,
> this has cropped up on a production system, and so we're trying to
> reproduce it in our test environment.  Naturally, we're looking at
> the TCP/IP stack configuration, among other stuff.  In the meantime,
> however, I wondered if anyone knows which bits I ought to be prodding
> at to look for sub-optimal libraries, &c.; or whether anyone else has
> run into similar problems on Solaris or elsewhere.
>
> A
>
> --
> ----
> Andrew Sullivan                         204-4141 Yonge Street
> Liberty RMS                           Toronto, Ontario Canada
> <>                              M2P 2A8
>                                          +1 416 646 3304 x110
>
>
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>

Marc G. Fournier                   ICQ#7615664               IRC Nick: Scrappy
Systems Administrator @ hub.org
primary:            secondary: scrappy@{freebsd|postgresql}.org


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