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From Tim Casey <tca...@gmail.com>
Subject Re: Spatial Search based on the amount of docs, not the distance
Date Fri, 23 Jun 2017 00:34:21 GMT
deniz,

I was going to add something here.  The reason what you want is probably
hard to do is because you are asking solr, which stores a document, to
return documents using an attribute of document pairs.  As only a though
exercise, if you stored record pairs as a single document, you could
probably query it directly.  That is, if you have d1 and d2 and you are
querying  around d1 and ordering by distance, then you could get this
directly from a document representing a record pair.  I don't think this is
practical, because it is an n^2 store.

Since the n^2 problem is there, people are going to suggest some heuristic
which avoids this problem.  What Erick is suggesting is down this path.
Query around a point and sort by distance taking the top K results.  The
result is taking a linear slice of the n^2 distance attribute.

tim



On Wed, Jun 21, 2017 at 7:50 PM, Erick Erickson <erickerickson@gmail.com>
wrote:

> Would it serve to sort by distance? True, if you matched a zillion
> documents within a 1km radius you'd still perform the distance calcs, but
> the result would be a manageable number.
>
> I have to ask "Why to you care?". Is this an efficiency question (i.e. you
> want to keep Solr from having to do expensive work) or is it a question of
> having to get hits at all? It's at least possible that the solution for one
> is not the solution for the other.
>
> Best,
> Erick
>
> On Wed, Jun 21, 2017 at 5:32 PM, deniz <denizdurmus87@gmail.com> wrote:
>
> > it is for sure possible to use d value for limiting the distance,
> however,
> > it
> > might not be very efficient, as some of the coords may not have any docs
> > around for a large value of d... so it is hard to determine a default
> value
> > for d.
> >
> > though it sounds like havinga default d and gradual increments on its
> value
> > might be a work around for top K results...
> >
> >
> >
> >
> >
> > -----
> > Zeki ama calismiyor... Calissa yapar...
> > --
> > View this message in context: http://lucene.472066.n3.
> > nabble.com/Spatial-Search-based-on-the-amount-of-docs-not-the-distance-
> > tp4342108p4342258.html
> > Sent from the Solr - User mailing list archive at Nabble.com.
> >
>

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