XML DB: using default namespace gives different result

Question

In Oracle9i R2 I created an XMLTYPE table based on a XML schema. The schema uses a namespace. When I insert an instance document that has a namespace prefix for every element querying works fine. When I insert an instance document that has the namespace defined as the default namespace, the query returns an empty row for that document. It seems to me that before storing the document the namespaces must be expanded and hence there should be no difference between the two documents and the query should return a value for both rows. Any thoughts? Thanks in advance! Below is the script and the results of the queries.
==========
THE SCRIPT
==========
DROP TABLE islands_xsd
BEGIN
DBMS_XMLSCHEMA.DELETESCHEMA('http://www.cumquat.nl/xsd/island.xsd', DBMS_XMLSCHEMA.DELETE_CASCADE);
END;
BEGIN
DBMS_XMLSCHEMA.REGISTERSCHEMA('http://www.cumquat.nl/xsd/island.xsd',
'<?xml version="1.0"?>
<schema targetNamespace="http://www.cumquat.nl/xsd/island.xsd"
xmlns:isl="http://www.cumquat.nl/xsd/island.xsd"
xmlns="http://www.w3.org/2001/XMLSchema">
<element name="island" type="isl:islandType"/>
<complexType name="islandType">
<sequence>
<element name="name" type="string"/>
<element name="country" type="string"/>
<element name="total_area" type="positiveInteger"/>
<element name="shoreline" type="positiveInteger"/>
<element name="pop_density" type="integer"/>
<element name="dist_continent" type="integer"/>
</sequence>
</complexType>
</schema>');
END;
CREATE TABLE islands_xsd OF XMLTYPE
XMLSCHEMA "http://www.cumquat.nl/xsd/island.xsd"
ELEMENT "island"
INSERT INTO islands_xsd VALUES (XMLTYPE(
'<?xml version="1.0"?>
<isl:island xmlns:isl="http://www.cumquat.nl/xsd/island.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.cumquat.nl/xsd/island.xsd http://www.cumquat.nl/xsd/island.xsd">
<isl:name>Aldabra</isl:name>
<isl:country>Seychelles</isl:country>
<isl:total_area>13</isl:total_area>
<isl:shoreline>104</isl:shoreline>
<isl:pop_density>0</isl:pop_density>
<isl:dist_continent>6</isl:dist_continent>
</isl:island>'))
INSERT INTO islands_xsd VALUES (XMLTYPE(
'<?xml version="1.0"?>
<island xmlns="http://www.cumquat.nl/xsd/island.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.cumquat.nl/xsd/island.xsd http://www.cumquat.nl/xsd/island.xsd">
<name>Amsterdam</name>
<country>France</country>
<total_area>9</total_area>
<shoreline>51</shoreline>
<pop_density>0</pop_density>
<dist_continent>30</dist_continent>
</island>'))
SELECT i.EXTRACT('/isl:island/isl:name', 'xmlns:isl="http://www.cumquat.nl/xsd/island.xsd"')
FROM islands_xsd i
SELECT i.EXTRACT('/isl:island/isl:name', 'xmlns:isl="http://www.cumquat.nl/xsd/island.xsd"').GETSTRINGVAL()
FROM islands_xsd i
SELECT i.EXTRACT('/isl:island/isl:name/text()', 'xmlns:isl="http://www.cumquat.nl/xsd/island.xsd"').GETSTRINGVAL()
FROM islands_xsd i
=======================================
THE RESULTS OF RUNNING THE QUERIES
=======================================
SQL> SELECT i.EXTRACT('/isl:island/isl:name', 'xmlns:isl="http://www.cumquat.nl/xsd/island.xsd"')
2 FROM islands_xsd i
3 /
I.EXTRACT('/ISL:ISLAND/ISL:NAME','XMLNS:ISL="HTTP://WWW.CUMQUAT.NL/XSD/ISLAND.XS
XMLTYPE()
2 rows selected.
SQL> SELECT i.EXTRACT('/isl:island/isl:name', 'xmlns:isl="http://www.cumquat.nl/xsd/island.xsd"').GE
TSTRINGVAL()
2 FROM islands_xsd i
3 /
I.EXTRACT('/ISL:ISLAND/ISL:NAME','XMLNS:ISL="HTTP://WWW.CUMQUAT.NL/XSD/ISLAND.XS
<isl:name xmlns:isl="http://www.cumquat.nl/xsd/island.xsd">Aldabra</isl:name>
2 rows selected.
SQL> SELECT i.EXTRACT('/isl:island/isl:name/text()', 'xmlns:isl="http://www.cumquat.nl/xsd/island.xs
d"').GETSTRINGVAL()
2 FROM islands_xsd i
3 /
I.EXTRACT('/ISL:ISLAND/ISL:NAME/TEXT()','XMLNS:ISL="HTTP://WWW.CUMQUAT.NL/XSD/IS
Aldabra
2 rows selected.

Answer 1

This seems wrong to me. I've filed Bug 2400119 to get this looked into by development.
I'd expect any document with an appropriate qualified name to be found by your XPath expression, irrespective of whether syntactically one of the documents happened to use the default namespace syntax.