Re: index on points

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От
Tom Lane
Тема
Re: index on points
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Msg-id
19545.971195784@sss.pgh.pa.us
Ответ на
Re: index on points (Jeff Hoffmann)
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Re: index on points Jeff Hoffmann <jeff@propertykey.com>
Re: index on points Tom Lane <tgl@sss.pgh.pa.us>
Jeff Hoffmann  writes:
> Tom Lane wrote:
>> There is already support for r-tree indexes, but as far as I know the
>> '@' operator is not connected up to indexes.

> i'm just throwing this out without testing it, but i think something
> like this might work:  coerce both the point and polygon into boxes (i
> think box(polygon) gives you the bounding box, at least) and use the
> overlap (&&) operator, which works fine with r-tree indexes on two
> boxes, then use the contained operator (@) on what you get from that.

Right, that's pretty much exactly what index support for @ would do for
you under-the-hood.  I wouldn't expect the index to give you an answer
finer-grained than bounding boxes, so you'd still need to run @ itself
on the candidates found by the indexable query.

Jeff has a good point that doing the transformation by hand might be
an acceptable answer for the time being.  You can hack a lot of queries
in the time it will take to teach the system to do that same
transformation ...

			regards, tom lane
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