The limit on vertex count for features stored in SDO_GEOMETRY is 1048576 divided by the number of dimensions in the geometry.
This limit is implicit in the structure of SDO_GEOMETRY. SDO_GEOMETRY.SDO_ORDINATES, the portion that contains the ordinates, is defined as a VARRAY(1048576). The defined size of a VARRAY is its maximum size.
Only applications that deal with very complex geometries are likely to encounter this limitation.
Starting at Oracle 11g R2, it is possible to increase this size limitation to 10M ordinates. See 'Increasing the Size of Ordinate Arrays to Support Very Large Geometries' in the Related Information for more information.