| From: | Markus Schiltknecht <markus(at)bluegap(dot)ch> |
|---|---|
| To: | Jan Wieck <JanWieck(at)Yahoo(dot)com> |
| Cc: | Mario Weilguni <mario(dot)weilguni(at)icomedias(dot)com>, Chris Browne <cbbrowne(at)acm(dot)org>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Replication on the backend |
| Date: | 2005-12-07 07:42:55 |
| Message-ID: | 1133941375.7568.9.camel@localhost.localdomain |
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| Lists: | pgsql-hackers |
On Tue, 2005-12-06 at 23:19 -0500, Jan Wieck wrote:
> It's not so much the bandwidth but more the roundtrips that limit your
> maximum transaction throughput.
I completely agree that the latency is counting, not the bandwith.
Does anybody have latency / roundtrip measurements for current hardware?
I'm interested in:
1Gb Ethernet,
10 Gb Ethernet,
InfiniBand,
probably even p2p usb2 or firewire links?
At least Quadrics claims(1) to have measured only 1.38 microseconds.
Assuming real world condition would give you 5 microseconds, on a 3 GHz
processor that's 15'000 CPY cycles. Which is IMHO not that much any
more. Or am I wrong (mental arithmetic never was my favourite subject)?
Regards
Markus
[1]
http://www.quadrics.com/quadrics/QuadricsHome.nsf/NewsByDate/98FFE60F799AC95180256FEA002A6D9D
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