Re: unnest multirange, returned order

>
> I'd say that the storag order is the order in which PostgreSQL stores
> multiranges internally:

Right, I believe that you are right but then this information is not useful
for the developer.
If storage order is always ascending by range order then let's make it
clear, if order cannot be counted upon as it may evolve from postgres
version to version, then let's make it clear as well. WDYT ?

Thank you.
Daniel Fredouille

Le mar. 3 oct. 2023 à 09:46, Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> a
écrit :

> On Mon, 2023-10-02 at 18:42 +0000, PG Doc comments form wrote:
> > Page: https://www.postgresql.org/docs/16/functions-range.html
> >
> > The doc says:
> > * unnest ( anymultirange ) → setof anyrange
> > * Expands a multirange into a set of ranges. The ranges are read out in
> > storage order (ascending).
> >
> > What is storage order ?
> >
> > At first I thought that it was the order in which the different ranges
> are
> > inserted in the internal data structure. However, the following sort of
> > shows that it is not:
> > ```
> > postgres=# select unnest('{[1,4), [8,10)}'::int4multirange + '{[-5,-3)}'
> -
> > '{[2,3)}') ;
> > unnest
> > ---------
> > [-5,-3)
> > [1,2)
> > [3,4)
> > [8,10)
> > (4 lignes)
> > ```
> > Whatever I try, it always return in range order instead of "storage
> order".
>
> I'd say that the storag order is the order in which PostgreSQL stores
> multiranges internally:
>
> SELECT '{[100,200),[-100,-50),[-1,2)}'::int4multirange;
>
> int4multirange
> ═══════════════════════════════
> {[-100,-50),[-1,2),[100,200)}
> (1 row)
>
> Yours,
> Laurenz Albe
>