Re: index on points

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Jeff Hoffmann <jeff(at)propertykey(dot)com>
Cc: Peter Keller <peter(dot)keller(at)bvv(dot)bayern(dot)de>, pgsql-general(at)postgresql(dot)org
Subject: Re: index on points
Date: 2000-10-10 16:36:24
Message-ID: 19545.971195784@sss.pgh.pa.us
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Jeff Hoffmann <jeff(at)propertykey(dot)com> 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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