Re: pg_stats and range statistics

On Sun, Jan 22, 2023 at 07:19:41PM +0100, Tomas Vondra wrote:
> On 1/21/23 19:53, Egor Rogov wrote:
> > Hi Tomas,
> > On 21.01.2023 00:50, Tomas Vondra wrote:
> >> This simply adds two functions, accepting/producing anyarray - one for
> >> lower bounds, one for upper bounds. I don't think it can be done with a
> >> plain subquery (or at least I don't know how).
> >
> > Anyarray is an alien to SQL, so functions are well justified here. What
> > makes me a bit uneasy is two almost identical functions. Should we
> > consider other options like a function with an additional parameter or a
> > function returning an array of bounds arrays (which is somewhat
> > wasteful, but probably it doesn't matter much here)?
> >
>
> I thought about that, but I think the alternatives (e.g. a single
> function with a parameter determining which boundary to return). But I
> don't think it's better.

What about a common function, maybe called like:

ranges_upper_bounds(PG_FUNCTION_ARGS)
{
AnyArrayType *array = PG_GETARG_ANY_ARRAY_P(0);
Oid element_type = AARR_ELEMTYPE(array);
TypeCacheEntry *typentry;

/* Get information about range type; note column might be a domain */
typentry = range_get_typcache(fcinfo, getBaseType(element_type));

return ranges_bounds_common(typentry, array, false);
}

That saves 40 LOC.

Shouldn't this add some sql tests ?

--
Justin