Had a fun discovery today: a user tried to do the following (perfectly
reasonable) thing:

bag_sizes = foreach grouped_data genrate
  group, SIZE(grouped_data);

.. and it was excessively slow, because SIZE is not algebraic.

I had him switch to COUNT_STAR, and that worked, of course.

But he reasonably pointed out that SIZE should work, too. It's documented to
work on bags, after all.

I tried switching SIZE's argToFunc mapping to return
COUNT_STAR.class.getName(), but discovered much to my dismay that algebraic
optimization still does not get invoked.

Presumably because we check if SIZE is instanceof Algebraic, instead of
checking the class that's returned by argToFuncMapping.

Is that about right? Do you guys agree that's a bug?

D

Yup, that makes sense. Class returned by argToFuncMapping needs to implement
Algebraic instead of EvalFunc itself.

Ashutosh
On Mon, Aug 29, 2011 at 15:46, Dmitriy Ryaboy <[EMAIL PROTECTED]> wrote:

> Had a fun discovery today: a user tried to do the following (perfectly
> reasonable) thing:
>
> bag_sizes = foreach grouped_data genrate
>  group, SIZE(grouped_data);
>
> .. and it was excessively slow, because SIZE is not algebraic.
>
> I had him switch to COUNT_STAR, and that worked, of course.
>
> But he reasonably pointed out that SIZE should work, too. It's documented
> to
> work on bags, after all.
>
> I tried switching SIZE's argToFunc mapping to return
> COUNT_STAR.class.getName(), but discovered much to my dismay that algebraic
> optimization still does not get invoked.
>
> Presumably because we check if SIZE is instanceof Algebraic, instead of
> checking the class that's returned by argToFuncMapping.
>
> Is that about right? Do you guys agree that's a bug?
>
> D
>

Wow this is so much less trivial than I thought it was going to be! :)

D

On Mon, Aug 29, 2011 at 9:36 PM, Ashutosh Chauhan <[EMAIL PROTECTED]>wrote:

> Yup, that makes sense. Class returned by argToFuncMapping needs to
> implement
> Algebraic instead of EvalFunc itself.
>
> Ashutosh
> On Mon, Aug 29, 2011 at 15:46, Dmitriy Ryaboy <[EMAIL PROTECTED]> wrote:
>
> > Had a fun discovery today: a user tried to do the following (perfectly
> > reasonable) thing:
> >
> > bag_sizes = foreach grouped_data genrate
> >  group, SIZE(grouped_data);
> >
> > .. and it was excessively slow, because SIZE is not algebraic.
> >
> > I had him switch to COUNT_STAR, and that worked, of course.
> >
> > But he reasonably pointed out that SIZE should work, too. It's documented
> > to
> > work on bags, after all.
> >
> > I tried switching SIZE's argToFunc mapping to return
> > COUNT_STAR.class.getName(), but discovered much to my dismay that
> algebraic
> > optimization still does not get invoked.
> >
> > Presumably because we check if SIZE is instanceof Algebraic, instead of
> > checking the class that's returned by argToFuncMapping.
> >
> > Is that about right? Do you guys agree that's a bug?
> >
> > D
> >
>