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Re: 9.3 Pre-proposal: Range Merge Join - Mailing list pgsql-hackers

From Alexander Korotkov
Subject Re: 9.3 Pre-proposal: Range Merge Join
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Msg-id CAPpHfdtUpXaCXHbnted+jURpXg3g+cCrtk0C618YzqUtibsE_g@mail.gmail.com
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In response to Re: 9.3 Pre-proposal: Range Merge Join  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
Responses Re: 9.3 Pre-proposal: Range Merge Join
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On Mon, Apr 16, 2012 at 10:29 AM, Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> wrote:
On 16.04.2012 08:40, Jeff Davis wrote:
Does someone know of a spatial join algorithm (without IP claims) that
would be as good as this one for ranges?

I'd be happy with an algorithm that's specific to ranges, too, but my gut geeling is that there has to be a lot of research on spatial join algorithms out there. Implementing one of them would be more widely applicable, so I think we should look into spatial join algorithms first and see how far that gets us, before we write something specific to ranges.

There is a good overview article about spatial joins.
It shows that there is a lot of methods based on building temporaty indexes. It might mean that building of temporary GiST index is not a bad idea.
Also there are methods which looks like extension of Jeff Davis proposal to the multidimensional case. It is Plane Sweep and External Plane Sweep methods. However, it might use sophisticated data structures for the "sweep". And I believe it should use it for good performance.

------
With best regards,
Alexander Korotkov.

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