On Tue, Jan 29, 2013 at 11:42 AM, Peilke, Hendrik
<[email protected]>wrote:
> Hello,
>
>
>
> I am using GeoTools together with udig and Oracle Spatial. Loading a layer
> with geometries from a table takes a lot of time, if the connection was not
> established with the owner of the table. And even when using the core
> owner, loading from large geometry tables took about 30 seconds. While
> investigating the problem, I found out that the part which takes such a
> long time is the retrieval of the geometry bounds of the table. I noticed
> that two ways exist:
>
>
>
> 1) by using SDO_TUNE.EXTENT_OF
>
> 2) by using SDO_AGGR_MBR
>
>
>
> Our geometry tables are managed the following way: All GIS users have
> synonyms for the geometry tables of the gis core user, which makes the
> first variant fail for the GIS users and explains the slowness by the
> fallback to the second way. But even for large tables and with the gis core
> user the first way takes quite a time.
>
>
>
> In Oracle Spatial there should also be a third, much faster way:
> dimensional bounds (DIMINFO) are laid down by the user in the
> ALL_SDO_GEOM_METADATA table, which is already used for retrieving the SRID.
> So a lot of speedup would be possible if that column would be also
> retrieved while getting the SRID.
>
>
>
> At the moment I don’t see any argument against this third way. What do you
> think?
>
The third way was originally supported by the old Oracle store, but the
vast majority of users entered fake information
in those tables, so it has been dropped.
If someone wants to implement it back it would be appreciated, but it would
also have to be subjected to a flag enabling
it, and should be disabled by default
Cheers
Andrea
--
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