Re: add modulo (%) operator to pgbench

On Wed, Sep 10, 2014 at 4:48 AM, Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> wrote:
> Note I did not start with the non uniform stuff, but Mitsumasa-san sent a
> gaussian distribution patch and I jumped onto the wagon to complement it
> with an exponential distribution patch. I knew when doing it that is was not
> enough, but as I said "one piece at a time", given the effort required to
> pass simple patch.
>
> What is still needed for the overall purpose is the ability to scatter the
> distribution. This is really:
>
> (1) a positive remainder modulo, which is the trivial patch under
> discussion
>
> (2) a fast but good quality for the purpose hash function
> also a rather small patch, not submitted yet.
>
> (3) maybe the '|' operator to do a TP*-like non-uniform load,
> which is really periodic so I do not like it.
> a trivial patch, not submitted yet.
>
> If you do not want one of these pieces (1 & 2), basically the interest of
> gaussian/exponential addition is much reduced, and this is just a half baked
> effort aborted because you did not want what was required to make it useful.
> Well, I can only disagree, but you are a committer and I'm not!

I am not objecting to the functionality; I'm objecting to bolting on
ad-hoc operators one at a time. I think an expression syntax would
let us do this in a much more scalable way. If I had time, I'd go do
that, but I don't. We could add abs(x) and hash(x) and it would all
be grand.

--
Robert Haas
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