Re: gaussian distribution pgbench

(2014/03/03 16:51), Fabien COELHO wrote:>>> \setrandom foo 1 10 [uniform]
>>> \setrandom foo 1 :size gaussian 3.6
>>> \setrandom foo 1 100 exponential 7.2
>> It's good design. I think it will become more low overhead at part of parsing
>> in pgbench, because comparison of strings will be redeced(maybe). And I'd like
>> to remove [uniform], beacause we have to have compatibility for old scripts,
>> and random function always gets uniform distribution in common sense of
>> programming.
>
> I just put "uniform" as an optional default, hence the brackets.
All right. I was misunderstanding. However, if we select this format, I'd like to
remove it. Because pgbench needs to check counts of argment number. If we allow
brackets, it will not be simple.

> Otherwise, what I would have in mind if this would be designed from scratch:
>
> \set foo 124
> \set foo "string value" (?)
> \set foo :variable
> \set foo 12 + :shift
>
> And then
>
> \set foo uniform 1 10
> \set foo gaussian 1 10 4.2
> \set foo exponential 1 100 5.2
>
> or maybe functions could be repended with something like "&uniform".
> But that would be for another life:-)
I don't agree with that.. They are more overhead in parsing part and more complex
for user.

>> However, new grammer is little bit long in user script. It seems trade-off that
>> are visibility of scripts and user writing cost.
>
> Yep.
OK. I'm not sure which idia is the best. So I wait for comments in community:)

Regards,
--
Mitsumasa KONDO
NTT Open Source Software Center