Re: add modulo (%) operator to pgbench

* Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
> Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> writes:
> > So my opinion is that this small modulo operator patch is both useful and
> > harmless, so it should be committed.
>
> You've really failed to make that case --- in particular, AFAICS there is
> not even consensus on the exact semantics that the operator should have.
> So I'm inclined to reject rather than put in something that may cause
> surprises down the road. The usefulness doesn't seem great enough to
> take that risk.

Agreed.

> The way forward, if we think there is enough value in it (I'm not
> sure there is), would be to build enough expression infrastructure
> so that we could inexpensively add both operators and functions.
> Then we could add a modulo operator with whatever semantics seem
> most popular, and some function(s) for the other semantics, and
> there would not be so much riding on choosing the "right" semantics.

Indeed and there's plenty of time to make it happen for 9.5.
Personally, I'd really like to see as I feel it'd help with the
performance farm goal which has been discussed many times over.

Fabien, I'd ask that you not be discouraged by this and continue to work
with pgbench and work on such an improvement, if you're able to take it
on with your other committments. I do see value in it and I feel it
will help reproducability, a key and important aspect of performance
analysis, much more so than just hacking a local copy of pgbench would.

Thanks!

Stephen