UNDO exhaustion whilst performing validate_layer_with_context

Question

Trying to track down an ArcSDE problem, I've been performing validation on the layers we have loaded into Oracle Spatial. One table (part of OS Mastermap) containing 400 million features will not complete a validation, after several hours of processing and 24GB o consumed UNDO the following error is reported.
SQL> execute sdo_geom.validate_layer_with_context('TOPOGRAPHIC_LINE', 'SHAPE',
'TOPOGRAPHIC_LINE_VAL', 100);
--After 8+ hours of processing
BEGIN sdo_geom.validate_layer_with_context('TOPOGRAPHIC_LINE', 'SHAPE', 'TOPOGRA
PHIC_LINE_VAL', 100); END;
ERROR at line 1:
ORA-29400: data cartridge error
ORA-30036: unable to extend segment by 8 in undo tablespace 'UNDOTBS1'
ORA-06512: at "MDSYS.SDO_3GL", line 439
ORA-06512: at "MDSYS.SDO_GEOM", line 3860
ORA-06512: at line 1
The topographic_line_val contains no records before or after running the validate procedure.
I'm sure I've missed something fundamental, but I can't see why so much UNDO should be necessary. Nothing is running a long running query on the val table, the procedure doesn't modify the topographic_line table and the commit internval is set to only 100.
Why is so much UNDO being consumed?
Should I just keep increasing the amount of UNDO tablespace available until it completes?
Is it a particularly bad idea to fake validate_layer(_with_context), using validate_geometry and a loop?
Could I be running into a Spatial bug? The database is at patch level 9.2.0.6
With thanks, Alex

Answer 1

IMHO, call support, it sounds like a bug (using it on a larger dataset than it was ever tested with).
Have you thought about using VALIDATE_GEOMETRY_WITH_CONTEXT instead? It might be a hair slower, but since it is called once per row, at least it won't blow up:
CREATE TABLE geom_errors (rowid_text CHAR(18), error_text CLOB);
INSERT INTO geom_errors (
SELECT * FROM
(SELECT a.ROWID, SDO_GEOM.VALIDATE_GEOMETRY_WITH_CONTEXT(a.shape, 0.5) the_error
FROM topographic_line a)
WHERE the_error != 'TRUE');