Message-ID: <d19b98ba046785d82df866388180282f@smtp.hushmail.com>
From: Chris Mair <chris@1006.org>
To: pgsql-performance@postgresql.org
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Subject: Re: [pgsql-performance] function difference(geometry,
	geometry) is SLOW!
Date: Mon, 16 Jun 2008 21:26:14 +0200

 >
 > Date: Mon, 16 Jun 2008 11:06:44 +0200 (CEST)
 > From: "luke.78@libero.it" <luke.78@libero.it>
 > To: pgsql-performance@postgresql.org
 > Subject: function difference(geometry,geometry) is SLOW!
 > Message-ID:
 > <10574478.390451213607204584.JavaMail.defaultUser@defaultHost>
 >
 > Hi,
 > In my pgsql procedure, i use the function
 >
 > geometryDiff := difference
 > (geometry1,geometry2);
 >
 > but this function is very slow!!!
 > What can I do to
 > speed this function?
 > Exists a special index for it?
 >
 > Thanks in advance!
 > Luke

Hi,

this is a postgis function. Postgis is an independent project
and you might want to ask there:

http://www.postgis.org/mailman/listinfo/postgis-users

or

http://www.faunalia.com/cgi-bin/mailman/listinfo/gfoss
(italian).

Anyway, as long as you just compute the difference between
2 given shapes, no index can help you. Indices speed up
searches...

Bye,
Chris.