Re: range_agg

On Thu, Mar 12, 2020 at 5:38 AM Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
> ... thinking about gist+spgist, I think they could be written
> identically to those for ranges, using the lowest (first) lower bound
> and the higher (last) upper bound.
>
> ... thinking about selectivity, I think the way to write that is to
> first compute the selectivity for the range across the first lower bound
> and the last upper bound, and then subtract that for the "negative"
> space between the contained ranges.
>
> I have no immediate thoughts about typanalyze.  I suppose it should be
> somehow based on the implementation for ranges ... maybe a first-cut is
> to construct fake ranges covering the whole multirange (as above) and
> just use the ranges implementation (compute_range_stats).

Thanks, this is pretty much what I was thinking too, but I'm really
glad to have someone who knows better confirm it. I can get started on
these right away, and I'll let folks know if I need any help. When I
looked at this last fall there was a lot I didn't understand. More or
less using the existing ranges implementation should be a big help
though.

Paul