Problem with generating xml and nested cursor (ora-600)

Question

I have a problem with generating xml (with dbms_xmlquery or xmlgen) and nested cursors.
When I execute the following command, I get a ORA-600 error:
select dbms_xmlquery.getxml('select mst_id
, mst_source
, cursor(select per.*
, cursor(select ftm_fdf_number
, ftm_value
from t_feature_master
where ftm_mstr_id = pers_master_id ) as features
from t_person per
where pers_master_id = mst_id ) as persons
from f_master
where mst_id = 3059435')
from dual;
<?xml version = '1.0'?>
<ERROR>oracle.xml.sql.OracleXMLSQLException: ORA-00600: internal error code, arguments: [kokbnp2], [1731], [], [], [], [], [], []
</ERROR>
The problem is the second cursor (t_feature_master).
I want to generate this:
<master>
<..>
<persons>
<..>
<features>
<..>
</features>
</persons>
<persons>
<..>
<features>
<..>
</features>
</persons>
</master>
If i execute the select-statement in sql-plus, then I get the next result.
MST_ID MST_SOURCE PERSONS
3059435 GG CURSOR STATEMENT : 3
CURSOR STATEMENT : 3
PERS_MASTER_ID PERS_TITLE PERS_INITI PERS_FIRSTNAME PERS_MIDDL PERS_LASTNAME
3059435 W. Name
CURSOR STATEMENT : 15
FTM_FDF_NUMBER FTM_VALUE
1 [email protected]
10 ....
I use Oracle 8.1.7.4 with Oracle XDK v9.2.0.5.0.
Is this a bug and do somebody know a workaround?

Answer 1

Very simple...Drop all type objects and nested tables and create them again. You will get no error. I'll explain the reason later.