On 20/12/13 09:36, Peter Geoghegan wrote:
On Thu, Nov 21, 2013 at 9:13 AM, Heikki Linnakangas
<hlinnakan...@vmware.com> wrote:
So what I'd actually like to see is \setgaussian, for use in custom scripts.
+1. I'd really like to be able to run a benchmark with a Gaussian and
uniform distribution side-by-side for comparative purposes - we need
to know that we're not optimizing one at the expense of the other.
Sure, DBT-2 gets you a non-uniform distribution, but it has serious
baggage from it being a tool primarily intended for measuring the
relative performance of different database systems. pgbench would be
pretty worthless for measuring the relative strengths and weaknesses
of different database systems, but it is not bad at informing the
optimization efforts of hackers. pgbench is a defacto standard for
that kind of thing, so we should make it incrementally better for that
kind of thing. No standard industry benchmark is likely to replace it
for this purpose, because such optimizations require relatively narrow
focus.
Sometimes I want to maximally pessimize the number of FPIs generated.
Other times I do not. Getting a sense of how something affects a
variety of distributions would be very valuable, not least since
normal distributions abound in nature.
Curious, wouldn't the common usage pattern tend to favour a skewed
distribution, such as the Poisson Distribution (it has been over 40
years since I studied this area, so there may be better candidates).
Just that gut feeling & experience tends to make me think that the
"Normal" distribution may often not be the best for database access
simulation.
Cheers,
Gavin
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