Re: [udig-users] Oracle: sdo_aggr_mbr vs user_sdo_geom_metadata

["Bergenroth, Brandon" <bbergenroth@xxxxxxx>]

I'm not so worried about uDig not using user_sdo_geom_metadata as much as it doing the full table scans to determine the mbr.  And then, doing the query on all tables even before I've picked one to actually display.

I'm a little surprised about the negative feedback about user_sdo_geom_metadata, it seems to me the users with problems having correct metadata would be the same users with problems having a correct crs!  

In fact, in my experience when loading data with a 3rd party tool like ESRI ArcCatalog, the metadata is inserted correctly with the proper bounds, but it's the crs (srid) that always shows up null.   

And Simon's solution suffers a bit as well, an index is not required, I might only want to display a particular layer at full extent and an index is just a waste in that case, but that is probably a rare occurrence compared to everything else.

I guess I've just always seen user_sdo_geom_metadata as a necessary part of having tables with sdo_geometry, so I make sure it is always populated correctly (same with geometry_columns in postgis).

Thanks,
Brandon



> -----Original Message-----
> From: udig-users-bounces@xxxxxxxxxxxxxxxxxxxxx [mailto:udig-users-
> bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of Simon Greener
> Sent: Thursday, August 19, 2010 5:16 AM
> To: udig-users@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re: [udig-users] Oracle: sdo_aggr_mbr vs
> user_sdo_geom_metadata
> 
> Greetings,
> (Jodie, I'm on holidays in NZ. Back Sept 3rd.)
> I learned  when programming GeoRaptor that you
> can access the root mbr of the Oracle RTree
> in user_sdo_index_metadata (column sdo_root_mbr).
> This is an sdo_geometry object. However,
> when it contains the mbr of a gedetix layer,
> we haven't worked out what the
> sdoordinates mean, as yet.
> But is is blindingly faat: better tahn aggr union.
> Code is in metedatatool.java in sourceforge repository.
> best i can do.
> simon
> On Thu, 19 Aug 2010 14:23:32 +1000, Jody Garnett
> <jody.garnett@xxxxxxxxx> wrote:
> 
> > Hi Brandon.
> >
> > We had the previous version of our oracle support use the geom
> > metadadata table; and I after treading the oracle manuals I though
> > this was the correct approach to determine bounds.
> >
> > I got lots of negative feedback; apparently this table is not often
> > filled in with the correct information and cannot be trusted.  With
> > that in mind, when geotools created their "jdbc-ng" rewrite for
> oracle
> > support they did not even considering taking the geom metadata table
> > code used previous.
> >
> > If you like we can make the feature request for GeoTools and see what
> they say.
> >
> > With respect to SELECT SDO_AGGR_MBR ... I had thought that we avoided
> > doing this for uDig 1.2.0 - instead assuming a default max extent
> > based on the coordinate reference system.
> >
> > When Maurcio returns from vacation we can ask him, he performed the
> > oracle testing for 1.2.0.
> >
> >
> > Jody
> >
> > On Thu, Aug 19, 2010 at 4:37 AM, Bergenroth, Brandon
> > <bbergenroth@xxxxxxx> wrote:
> >> I have yet to see uDig (including 1.2.0) use user_sdo_geom_metadata,
> >> instead, it seems to always insist on running
> >>
> >> SELECT SDO_AGGR_MBR(GEOMETRY) FROM BIG_SPATIAL_TABLE
> >>
> >> for every table in the schema.
> >>
> >> Will uDig ever use user_sdo_geom_metadata?  Running a full table
> scan on
> >> every spatial table makes it pretty much useless for anything but a
> >> trivial amount of data.
> >>
> >> Thanks,
> >> Brandon
> >>
> >>
> >>
> >> _______________________________________________
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> >>
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> >
> 
> 
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