Re: gaussian distribution pgbench -- splits Bv6 - Mailing list pgsql-hackers

From Fabien COELHO
Subject Re: gaussian distribution pgbench -- splits Bv6
Date
Msg-id alpine.DEB.2.10.1407242055050.3626@sto
Whole thread Raw
In response to Re: gaussian distribution pgbench -- splits v4  (Mitsumasa KONDO <kondo.mitsumasa@gmail.com>)
Responses Re: gaussian distribution pgbench -- splits Bv6  (Alvaro Herrera <alvherre@2ndquadrant.com>)
Re: gaussian distribution pgbench -- splits Bv6  (Mitsumasa KONDO <kondo.mitsumasa@gmail.com>)
List pgsql-hackers
> 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.

-- 
Fabien.

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