Re: Strange result: UNIX vs. TCP/IP sockets
От | The Hermit Hacker |
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Тема | Re: Strange result: UNIX vs. TCP/IP sockets |
Дата | |
Msg-id | 20030704143143.U45926@hub.org обсуждение исходный текст |
Ответ на | Strange result: UNIX vs. TCP/IP sockets (Andrew Sullivan <andrew@libertyrms.info>) |
Ответы |
Re: Strange result: UNIX vs. TCP/IP sockets
(Vincent van Leeuwen <pgsql.spam@vinz.nl>)
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Список | pgsql-performance |
'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 > <andrew@libertyrms.info> M2P 2A8 > +1 416 646 3304 x110 > > > ---------------------------(end of broadcast)--------------------------- > TIP 8: explain analyze is your friend > Marc G. Fournier ICQ#7615664 IRC Nick: Scrappy Systems Administrator @ hub.org primary: scrappy@hub.org secondary: scrappy@{freebsd|postgresql}.org
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