Re: pgbench - allow to specify scale as a size

On 17/02/18 12:17, Tom Lane wrote:
> Alvaro Hernandez <aht(at)ongres(dot)com> writes:
>> On 17/02/18 11:26, Tom Lane wrote:
>>> Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> writes:
>>>> Here is a attempt at extending --scale so that it can be given a size.
>>> I do not actually find this to be a good idea. It's going to be
>>> platform-dependent, or not very accurate, or both, and thereby
>>> contribute to confusion by making results less reproducible.
>>>
>>> Plus, what do we do if the backend changes table representation in
>>> some way that invalidates Kaarel's formula altogether? More confusion
>>> would be inevitable.
>>     Why not then insert a "few" rows, measure size, truncate the table,
>> compute the formula and then insert to the desired user requested size?
>> (or insert what should be the minimum, scale 1, measure, and extrapolate
>> what's missing). It doesn't sound too complicated to me, and targeting a
>> size is something that I believe it's quite good for user.
> Then you'd *really* have irreproducible results.
>
> regards, tom lane

    You also have irreproducible results today, according to your
criteria. Either you agree on the number of rows but may not agree on
the size (today), or you agree on the size but may not agree on the
number of rows. Right now you can only pick the former, while I think
people would significantly appreciate the latter. If neither is correct,
let's at least provide the choice.

    Regards,

    Álvaro

--

Alvaro Hernandez

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OnGres