I recently had difficulty running the geoprocessing tool Find Identical (arcpy.FindIdentical_management) in ArcMap - it was crashing with the unhelpful "999999: Error executing function." I eventually eliminated possibilities down to two very small ellipse polygons (as opposed to our typical multi-vertex polygons). Once i eliminated these two polygons, the tool ran fine on the remaining 200,000+ features.
I didn't find anything particularly helpful in the ST_Geometry functions (Oracle) that would help me query for an ellipse polygon next time I need to determine if I have some in my data. Even sde.st_astext(shape) spits out a significant list of coordinate pairs that I would guess would be the ellipse if generalized to multiple vertices.
A rather clumsy method in geoprocessing is to run the Feature Vertices to Points tool ("All" option) and summarize the output on the original feature identifier - ellipses appear to return only two output points (start and end point) opposed to the 3 or more points from a valid polygon composed of vertices.
Is there a better way to select records that use ellipse (and circle) types for their geometry? I'm not a ArcObjects programmer but that might be an alternative there if not in SQL or ArcPy? Thanks for any ideas! -S.