[postgis-devel] Btree operators

[Komяpa]

пн, 11 апр. 2016 г. в 16:38, Sandro Santilli <strk at keybit.net>:

> On Mon, Apr 11, 2016 at 11:06:40AM +0000, Komяpa wrote:
>
> > When I do SELECT DISTINCT geom, I want _distinct geometry_, not _geometry
> > with distinct boxes_. For distinct boxes I'd write SELECT DISTINCT on
> > (ST_Envelope(geom)) geom, and that's rather rare case. These two being
> > swapped really require mind-twisting, and the more mind-twisting it
> > requires the less people can use it.
> >
> > How about sorting by zig-zag-encoded coordinates?
>
> If equality has to be memcmp-like, comparision need to be memcmp-like too
> as I think it's a requirement for A=B to mean neither A < B  nor B < A.
>

This can be worked around by checking the memcmp-like ordering for case
when the zig-zag-encoded coordinates are the same.


> > Are there any showstoppers to implement this change, except of everyone
> has
> > to REINDEX?
>
> It's still missing a plan, as far as I can tell.


What's required for such a plan?
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