[postgis-users] Buffer bug ?

[Daniel]

As said in my last post, the problem come from the buffer() function.
(the collect() only take 345 ms)

I will try a geos update this afternoon and post the result here.

Sincerely yours,

dF

Mark Cave-Ayland wrote:

>>-----Original Message-----
>>From: postgis-users-bounces at postgis.refractions.net 
>>[mailto:postgis-users-bounces at postgis.refractions.net] On 
>>Behalf Of Daniel
>>Sent: 26 August 2005 13:13
>>To: Mark Cave-Ayland (External)
>>Cc: Arnaud Saint Léger; 'PostGIS Users Discussion'
>>Subject: Re: [postgis-users] Buffer bug ?
>>
>>
>>Hi,
>>
>>Thank u very much for your help. Here are precisions u requested:
>>    
>>
>
>(cut)
>
>  
>
>>6) splitting of the request:
>>
>>6.1) CREATE TABLE temp_lg_annee_bis AS SELECT * FROM 
>>lg_annee_bis WHERE lga_annee=2004 and lga_nat_cdn=2 and 
>>lga_var > -1; ---> 345 milliseconds
>>
>>6.2) buffer computing: the bug occur
>>    
>>
>
>
>Hi Daniel,
>
>Well it doesn't look as if it's a database tuning problem. Can you try and
>isolate the whether it is the buffer() or the collect() which is taking the
>time by trying your query without the buffer(), e.g.
>
>	BEGIN;
>	CREATE TABLE temp_lg_annee_bis AS SELECT * FROM lg_annee_bis WHERE
>lga_annee=2004 and lga_nat_cdn=2 and lga_var > -1;
>	SELECT collect(lga_geom) FROM temp_lg_annee_bis GROUP BY lga_annee;
>	ABORT;
>
>If it is the buffer() which is causing the slowdown then it's definitely
>worth trying upgrading to the latest GEOS release which is now 2.1.4.
>
>
>Kind regards,
>
>Mark.
>
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>  
>

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