WSO2 DSS call procedure with CLOB response raise ORA-22835 error - oracle

Question

I have a Oracle procedure
TEST_XML_PARM_CALLER
call procedure
TEST_XML_PARM_CALLEE(parm1 IN CLOB, parm2 OUT CLOB)
via WSO2 ESB, WSO2 DSS.
The parm1 is CLOB parameter, send XML content from procedure TEST_XML_PARM_CALLER,
and the parm2 is CLOB parameter that return XML content from procedure TEST_XML_PARM_CALLEE.
The call from TEST_XML_PARM_CALLER to ESB to DSS to TEST_XML_PARAM_CALLEE is correct by CLOB content (string length great than 4000),
but return parameter(parm2) will raise error when length great than 4000, like bellow
ORA-22835: Buffer too small for CLOB to CHAR or BLOB to RAW conversion (actual: 6024, maximum: 4000)
In WSO2 DSS, the configuration as below
<data name="test_xml_parm">
<config id="test_db">
<property name="carbon_datasource_name">test_db</property>
</config>
<query id="qry_test_xml_parm" useConfig="test_db">
<sql>call TEST_XML_PARM_CALLEE(?,?)</sql>
<result element="rcd" rowName="row">
<element column="rtn_clob" name="rtn_clob" xsdType="string"/>
</result>
<param name="clob_xml" ordinal="1" sqlType="STRING"/>
<param name="rtn_clob" ordinal="2" sqlType="STRING" type="OUT"/>
</query>
<operation name="op_test_xml_parm">
<call-query href="qry_test_xml_parm">
<with-param name="clob_xml" query-param="clob_xml"/>
</call-query>
</operation>
</data>
anyone can tell me how to fix it ?

Answer 1

This is an old question and I don't know about the wso2Dss version.
I had a similar problem with wso2DSS 4.4.2
1)set parameters sqlType to "CLOB"
2) replace ojdbc5.jar with ojdbc6.jar (or you will get java.lang.AbstractMethodError: setClob is abstract error.
I still have problems with xml (I must put input in CDATA and the response is ecaped (< => < ) but I should be able to deal with it on the ESB side.