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?
All the best
Hendrik
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