Gregory Stark wrote:
"Gaetano Mendola" <[EMAIL PROTECTED]> writes:
The following graph reports the results:
http://img84.imageshack.us/my.php?image=totalid7.png
That's a *fascinating* graph.
It is, isn't it? Thanks Gaetano.
It seems there are basically three domains.
The small domain where the database fits in shared buffers -- though actually
this domain seems to hold until the accounts table is about 1G so maybe it's
more that the *indexes* fit in memory. Here larger shared buffers do clearly
win.
I think this is actually in two parts - you can see it clearly on the
red trace (64MB), less so on the green (256MB) and not at all on the
blue (512MB). Presumably the left-hand steeper straight-line decline
starts with the working-set in shared-buffers, and the "knee" is where
we're down to just indexes in shared-buffers.
With the blue I guess you just get the first part, because by the time
you're overflowing shared-buffers, you've not got enough disk-cache to
take up the slack for you.
I wonder what difference 8.3 makes to this?
--
Richard Huxton
Archonet Ltd
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