[postgis-devel] Prepared Geometry API

[Paul Ramsey]

Exactly as one would expect: sometimes :)

P

On Mon, Oct 6, 2008 at 11:52 AM, Obe, Regina <robe.dnd at cityofboston.gov> wrote:
> What about using the PG_GETARG_POINTER does that return the same for all
> constants too?
>
> -----Original Message-----
> From: postgis-devel-bounces at postgis.refractions.net
> [mailto:postgis-devel-bounces at postgis.refractions.net] On Behalf Of Paul
> Ramsey
> Sent: Monday, October 06, 2008 2:48 PM
> To: PostGIS Development Discussion
> Subject: Re: [postgis-devel] Prepared Geometry API
>
> The answer seems to be that, for data in tables, this works OK, but
> for literals, it's possible for different literals to get the same
> datum number:
>
> select a.val as a, b.val as b, st_contains(a.val, b.val, 0) from
> (select 'POINT(0 0)' as val union select 'POINT(1 1)' as val) a,
> (select 'POINT(0 0)' as val union select 'POINT(1 1)' as val) b;
>
> This ends up returning the same datum number for 0,0 as well as 1,1. :(
>
> P.
>
> On Mon, Oct 6, 2008 at 11:23 AM, Paul Ramsey <pramsey at cleverelephant.ca>
> wrote:
>> Why can't I just this this:
>>
>> key1 = PG_GETARG_DATUM(0)
>> key2 = PG_GETARG_DATUM(1)
>>
>> the datums are just uint, and they don't get turned into pointers
>> until further down the line... I just tried changing my contains code
>> to do this, and I got the same answer in the same amount of time.  Are
>> the datum numbers reliable "object identifiers"?
>>
>> P.
>>
>> On Mon, Oct 6, 2008 at 10:53 AM, David Fuhry <dfuhry at acm.org> wrote:
>>> ctid will work for that, but I believe it would have to be passed
> into the
>>> function as a separate argument from the geometry, so API ugliness
> remains.
>>
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