Re: gaussian distribution pgbench -- splits Bv6

From: Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr>
To: Mitsumasa KONDO <kondo(dot)mitsumasa(at)gmail(dot)com>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, Andres Freund <andres(at)2ndquadrant(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: gaussian distribution pgbench -- splits Bv6
Date: 2014-07-24 19:03:16
Message-ID: alpine.DEB.2.10.1407242055050.3626@sto
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> Thank you for your grate documentation and fix working!!!
> It becomes very helpful for understanding our feature.

Hopefully it will help make it, or part of it, pass through.

> I add two feature in gauss_B_4.patch.
> 1) Add gaussianProbability() function
> It is same as exponentialProbability(). And the feature is as same as
> before.

Ok, that is better for readability and easy reuse.

> 2) Add result of "max/min percent of the range"
> It is almost same as --exponential option's result. However, max percent of
> the range is center of distribution
> and min percent of the range is most side of distribution.
> Here is the output example,

Ok, good that make it homogeneous with the exponential case.

> + pgbench_account's aid selected with a truncated gaussian distribution
> + standard deviation threshold: 5.00000
> + decile percents: 0.0% 0.1% 2.1% 13.6% 34.1% 34.1% 13.6% 2.1% 0.1% 0.0%
> + probability of max/min percent of the range: 4.0% 0.0%

> And I add the explanation about this in the document.

This is a definite improvement. I tested these minor changes and
everything seems ok.

Attached is a very small update. One word removed from the doc, and one
redundant declaration removed from the code.

I also have a problem with assert & Assert. I finally figured out that
Assert is not compiled in by default, thus it is generally ignored. So it
is more for debugging purposes when activated than for guarding against
some unexpected user errors.


Attachment Content-Type Size
gauss_B_6.patch text/x-diff 13.0 KB

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