[mapguide-users] Query for Oracle SDO Data without using SDO_FILTER

Andy Morsell amorsell at spatialgis.com
Mon Nov 20 11:20:41 EST 2006


If you are using MapGuide Open Source are you using the King Oracle Spatial
provider?  The only way to use the Autodesk Oracle Spatial provider is to
use MapGuide Enterprise.


Andy 

-----Original Message-----
From: Johann Nothbauer [mailto:nothbauer at rmdata.at] 
Sent: Monday, November 20, 2006 7:20 AM
To: OSGEO Mapguide Users
Subject: [mapguide-users] Query for Oracle SDO Data without using SDO_FILTER

Hi Andy!

I'm using Mapguide Open Source 1.0.2.
I could try to use Mapguide Enterprise, for we are a Autodesk Partner.

I'm only wondering how Mapguide would automatically decide when not to use
the Spatial Filter?

cheers,
Johann



Andy Morsell wrote (Date: Fri, 17 Nov 2006 08:54:22 -0800):

Are you using MapGuide Enterprise with Service Pack 1?  SP1 fixed quite a
few of the Oracle Spatial performance issues.


Andy

-----Original Message-----
From: Johann Nothbauer [mailto:nothbauer at rmdata.at]
Sent: Friday, November 17, 2006 3:55 AM
To: OSGEO Mapguide Users
Subject: [mapguide-users] Query for Oracle SDO Data without using SDO_FILTER

Is there any way to prevent Mapguide from using the SDO_FILTER()=='TRUE'
- Clause for Layers of Oracle Spatial Feature Sources?

I'm trying to produce an overview layer from an Oracle table containing a
lot of Line Features (> 2 million). The Features, that should be part of the
overview can be found with a very simple predicate (e.g.: "where layername =
'GG'") and are very few (< 1000). My problem is, that Mapguide always sends
a combined query (simple predicate plus spatial query with "extent all").
The Oracle explain plan shows, that internally ALL Features are fetched into
memory as a result of the spatial query only to be filtered with the much
"better" simple predicate.
I see this is a problem of the Oracle Cost Based Optimizer.

A nice workaround could be a "Don't use Spatial Filter" Checkbox in Mapguide
(as available in Oracle Mapviewer).

Would this be possible for the currrent Design?



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