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From Adam Kocoloski <kocol...@apache.org>
Subject Re: Did not understand this part about CouchDB
Date Sat, 13 Jul 2013 18:56:43 GMT
It's certainly easy to get turned around in these sorts of discussions.  Consider the case
where the incoming request rate is fixed and roughly independent of the server's response
time.  If the latency to provide a response to each request is reduced (say, by a more efficient
implementation of some key algorithm) then the number of requests actively being processed
by the server at any given instant of time (i.e., the concurrency) will be reduced.

Turning it around, there's always going to be a level of concurrency that maxes out the capabilities
of the server.  Amdahl's law covers some of the mathematics involved if you're interested
in that sort of thing.  Increasing the request rate on a server that has already reached the
land of diminishing returns will necessarily cause the latency observed by the individual
clients to rise.

Adam

On Jul 13, 2013, at 1:17 PM, Yves S. Garret <yoursurrogategod@gmail.com> wrote:

> On Sat, Jul 13, 2013 at 1:14 PM, Yves S. Garret
> <yoursurrogategod@gmail.com>wrote:
> 
>> Hello, I was reading about CouchDB here:
>> http://guide.couchdb.org/editions/1/en/why.html
>> 
>> The sentence is just above Figure 2 (which is roughly 2/3 of the way
>> down the page).  What I don't understand is why would concurrency
>> be impacted when latency is reduced?  Wouldn't latency reduce as
>> more processes are created to do more processing?
>> 
> 
> Or was this meant as a function of increased bandwith usage, as
> reads/writes increase, the latency is increased, yes?


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