From: | Stas Kelvich <s(dot)kelvich(at)postgrespro(dot)ru> |
---|---|
To: | Alexander Korotkov <aekorotkov(at)gmail(dot)com> |
Cc: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Sergey Konoplev <gray(dot)ru(at)gmail(dot)com>, Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Cube extension kNN support |
Date: | 2015-10-30 01:51:05 |
Message-ID: | 14876F35-0A31-444C-9914-E4C1978BDD80@postgrespro.ru |
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Lists: | pgsql-hackers |
Hello.
That is updated version of the patch with proper update scripts.
Also i’ve noted that documentation states the wrong thing:
“It does not matter which order the opposite corners of a cube are entered in. The cube functions automatically swap values if needed to create a uniform "lower left — upper right" internal representation."
But in practice cubes stored "as is" and that leads to problems with getting cubes sorted along specific dimension directly from index.
As a simplest workaround i’ve deleted that sentence from docs and implemented two coordinate getters -> and ~>. First one returns
coordinate of cube as it stored, and second returns coordinate of cube normalised to (LL,UR)-form.
Other way to fix thing is to force ’normalization’ while creating cube. But that can produce wrong sorts with already existing data.
> On 09 Jul 2015, at 16:40, Alexander Korotkov <aekorotkov(at)gmail(dot)com> wrote:
>
> Hi!
>
> On Sat, May 9, 2015 at 6:53 AM, Stas Kelvich <stas(dot)kelvich(at)gmail(dot)com> wrote:
> Patch is pretty ready, last issue was about changed extension interface, so there should be migration script and version bump.
> Attaching a version with all migration stuff.
>
> I can't see cube--1.0--1.1.sql in the patch. Did forget to include it?
>
> ------
> Alexander Korotkov
> Postgres Professional: http://www.postgrespro.com
> The Russian Postgres Company
Stas Kelvich
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
Attachment | Content-Type | Size |
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distances.patch | application/octet-stream | 68.9 KB |
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