I'd have to think about it more. But the FDT sketch was put in the library
as an example. With tuple sketches you would have to write the code that
encapsulates the tuple summary cells to do what you want and then extend
the summary aggregator to do the proper merge operations. So in a sense
the generic Tuple sketch provides the underlying machinery to handle the
approximate sampling and then you fill in the generic tuples with the
proper aggregator (perhaps another sketch) and set the union aggregator
function to properly feed those functions. So many such ideas are
potentially feasible, it just might require some serious thought about what
exactly you want it to do, and then code it and try it.
Cheers,
Lee.
On Fri, Jan 7, 2022 at 12:04 AM liupeng_wx <liupeng...@qq.com> wrote:
> hi all:
>
> i have a question at Frequent Distinct Tuples Sketch。 a multiset
> of tuples with N dimensions {d1,d2, d3, …, dN}，FDT could base on any of
> dimensions and approximate count distinct left dimensions。eg: *select
> appromate group by(d1,d2),count distinct {d2,...dn} from sketches group
> by **(d1,d2)*。 is there a way to group any of dimensions and count
> distinct any of left dimensions, eg: *select appromate group
> by(d1,d2),count distinct d3 from sketches group by (d1,d2)*
>
>
>
