Re: range_agg

čt 21. 11. 2019 v 21:15 odesílatel Paul Jungwirth <
pj(at)illuminatedcomputing(dot)com> napsal:

> On 11/21/19 1:06 AM, Pavel Stehule wrote:
> > 2. I don't like introduction "safe" operators - now the basic operators
> > are doubled, and nobody without documentation will use @* operators.
> >
> > It is not intuitive. I think is better to map this functionality to
> > basic operators +- * and implement it just for pairs (Multirange,
> > Multirange) and (Multirange, Range) if it is possible
> >
> > It's same relation line Numeric X integer. There should not be
> > introduced new operators. If somebody need it for ranges, then he can
> > use cast to multirange, and can continue.
> > [snip]
> > 3. There are not prepared casts -
> >
> > postgres=# select int8range(10,15)::int8multirange;
> > ERROR: cannot cast type int8range to int8multirange
> > LINE 1: select int8range(10,15)::int8multirange;
> > ^
> > There should be some a) fully generic solution, or b) possibility to
> > build implicit cast when any multirange type is created.
>
> Okay, I like the idea of just having `range + range` and `multirange +
> multirange`, then letting you cast between ranges and multiranges. The
> analogy to int/numeric seems strong. I guess if you cast a multirange
> with more than one element to a range it will raise an error. That will
> let me clean up the docs a lot too.
>

I though about it, and I think so cast from multirange to range is useless,
minimally it should be explicit.

On second hand - from range to multirange should be implicit.

The original patch did

1. MR @x MR = MR
2. R @x R = MR
3. MR @x R = MR

I think so @1 & @3 has sense, but without introduction of special operator.
@2 is bad and can be solved by cast one or second operand.

Pavel

> Thanks!
>
> --
> Paul ~{:-)
> pj(at)illuminatedcomputing(dot)com
>