SDO_GEOMETRY and Very Large Geometries

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04-21-2011 05:13 AM
StefanoIacovella
New Contributor III
Hello

The 11gR2 release of Oracle DB introduced support for features with a huge number of coordinates.
As you can see at

http://download.oracle.com/docs/cd/E11882_01/appdev.112/e11830/sdo_migrat.htm#CHDBCHBG

there is a script perfroming a radical mdofications of MDSYS schema. After it a SDO_ORDINATE_ARRAY conatins up to 10,000,000 values instead of 1,048,576.
I'm guessing if running this script on a Oracle Databse containing Geodatabase Feature Classes (with geometries stored in SDO_GEOMETRY fields) it is safe.
Is there any article or anyone has already upgraded?

Cheers

Stefano
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PaulDziemiela
New Contributor
Hi Stefano,

Funny how this topic only has suddenly come up in the last couple of weeks as 11gR2 has been out a while.  This past weekend I put out a post on the matter over on the Oracle Spatial OTN.
http://forums.oracle.com/forums/thread.jspa?threadID=2212186&tstart=0

I am just in the early stages of testing and far as I know no one else other than this guy
http://forums.oracle.com/forums/thread.jspa?threadID=2211540&tstart=0
has ever made a peep on the matter on a public forum.

My initial testing seems to be that ArcSDE is oblivious to the change in the data type definition.  A big issue is being able to move data between standard and uber SDO_GEOMETRY instances.  I found that sdeimport and sdeexport seemed to work just fine between the two (kind of obvious but you never know).  With datapump being out of the question and only the unsupported exp/imp tools available for moving stuff around, the sde tools and ArcCatalog might be a very good choice for such tasks.  Now its another question whether the folks at ESRI will officially support uber SDO.  Yet to some degree it really shouldn't matter.

So I can't answer your question as to whether it is "safe".  I am not at the point yet to make a recommendation.  On one hand just what are we supposed to do with these big polygons?  Sure, I know what ESRI recommends of course, but I have lots of Oracle Spatial applications in the pipeline can cannot utilize SDE.ST_GEOMETRY for them.  On the other hand once you "go large" suddenly you lose all the easy interoperability that makes SDO so much nicer than SDE.ST_GEOMETRY.  Datapump is out, database links are out, transportable tablespaces (I think) are out.  I am still sitting on the fence and very much interested in other folks' comments. 

I might ask, why do you want to do this?  I work in environmental science so I am using datasets that mainly model hydrology.  I wonder sometimes if its just me and my datasets that are the problem.  Everyone else modeling tax parcels and such just think this is all nuts.

Ideally we should try to keep this thread tied to the ArcSDE questions.  Do post the Oracle specific questions over on OTN if you have em.

Cheers,

Paul
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