# Re: [HACKERS] gaussian distribution pgbench

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```For example,  when we set the number of transaction 10,000 (-t 10000),
range of aid is 100,000,
and --exponential is 10, decile percents is under following as you know.```
```
decile percents: 63.2% 23.3% 8.6% 3.1% 1.2% 0.4% 0.2% 0.1% 0.0% 0.0%
highest/lowest percent of the range: 9.5% 0.0%

They mean that,
#number of access in range of aid (from decile percents):
1 to 10,000             => 6,320 times
10,001 to 20,000    => 2,330 times
20,001 to 30,000    => 860 times
...
90,001 to 10,0000  => 0 times

#number of access in range of aid (from highest/lowest percent of the
range):
1 to 1,000                => 950 times
...
99,001 to 10,0000   => 0 times

that's all.

Their information is easy to understand distribution of access probability,
isn't it?
Maybe I and Fabien-san have a knowledge of mathematics, so we think decile
percentage is common sense.
But if it isn't common sense, I agree with adding about these explanation
in the documents.
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What we are talking about is the "summary" at the end of the run, which is expected to be compact, hence the terse few lines.
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I'm not sure how to make it explicit without extending the summary too much, so it would not be a summary anymore:-)
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My initial assumption is that anyone interested enough in changing the default uniform distribution for a test would know about decile, but that seems to be optimistic.
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Maybe it would be okay to keep a terse summary but to expand the documentation to explain what it means, as you suggested above...
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--
Fabien.

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