On Sat, Jul 26, 2014 at 3:46 AM, Jiří Nádvorník
wrote:
> The reason why I solve the performance issues here is that the table of
> observations has atm cca 3e8 rows after 1.5 year of gathering the data. The
> number growth is linear.
>
So about 500,000 new records a day.
July 28, 2014 5:03 PM
To: Oleg Bartunov
Cc: Jiří Nádvorník; pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Cursor + upsert (astronomical data)
Hi Jiri,
I understand your problem (and I actually have exactly the same in my sky
monitoring experiment). Unfortunately, I have no comple
Hi Jiri,
I’m really interested in those [clustering] algorithms and study them. But
> I would need somebody to point me directly at a specific algorithm to look
> at. The main problem with choosing the right one (which couldn’t get over
> even my university teacher) is that you don’t know the numb
: Jiří Nádvorník
Cc: pgsql-performance@postgresql.org; Sergey Karpov
Subject: Re: [PERFORM] Cursor + upsert (astronomical data)
Jiri,
as I understand your problem is called crossmatch ? I attach pdf of our work
in progress, where we compared several spatial indexing techniques, including
postgis
mance@postgresql.org
Subject: Re: [PERFORM] Cursor + upsert (astronomical data)
I am not sure I understand the problem fully, e.g. what to do if there are
observations A,B and C with A to B and B to C less then treshold and A to C
over treshold, but anyway.
Could you first apply a kind of g
s on one image with another
> 999 images overlapping it means 1 *1000^2).
>
>
>
> Best regards,
>
>
>
> Jiri Nadvornik
>
>
>
> *From:* tiv...@gmail.com [mailto:tiv...@gmail.com] *On Behalf Of *Vitalii
> Tymchyshyn
> *Sent:* Sunday, July 27, 2014 8:06 A
[Craig]
>>If you haven't looked at clustering algorithms yet, you might want to do so.
>>Your problem is a special case of clustering, where you have a large number
>>of small clusters. A good place to start is the overview on Wikipedia:
>>http://en.wikipedia.org/wiki/Cluster_analysis
According t
r
> 999 images overlapping it means 1 *1000^2).
>
>
>
> Best regards,
>
>
>
> Jiri Nadvornik
>
>
>
> *From:* tiv...@gmail.com [mailto:tiv...@gmail.com] *On Behalf Of *Vitalii
> Tymchyshyn
> *Sent:* Sunday, July 27, 2014 8:06 AM
> *To:* Jiří Nádvorník
> *
: Jiří Nádvorník
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Cursor + upsert (astronomical data)
I am not sure I understand the problem fully, e.g. what to do if there are
observations A,B and C with A to B and B to C less then treshold and A to C
over treshold, but anyway.
Could
I am not sure I understand the problem fully, e.g. what to do if there are
observations A,B and C with A to B and B to C less then treshold and A to C
over treshold, but anyway.
Could you first apply a kind of grid to your observations? What I mean is
to round your coords to, say, 1/2 arcsec on ea
Hello guys.
My issue kind of hits multiple topics, but the main question is about
performance. I think you need to understand the background a little bit to
be able to help me. So I will firstly define the problem and my solutions to
it and place the questions for you to the end of this message
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