SQL data extracts works in Oracle 11g but not Oracle 12c

Question

When I execute the following SQL using TOAD against an Oracle 11g database, the fully formed XML is returned successfully:

With T As (SELECT dbms_xmlgen.getxml('SELECT m.trans_message FROM xml_nodes_ams_in a, message m WHERE a.id = m.msg_id AND a.UPN IN(''A30971016528VE8K'',''A30971016529VE84'') ORDER BY a.upn ASC'
  ) As output_xml from dual
) select dbms_xmlgen.Convert(output_xml,1) from T

However, when I execute the exact same SQL against our newly installed Oracle 12c database, some of the XML data appears to be missing (around 5000 characters).

I have discussed this with the DBA who reckons its a client issue rather than a database issue as he says there is no setting against the database that would cause this.

Has anyone got any advise on how I can progress this issue?

Answer 1

I raised a service request with Oracle and they came back to me and advised that there is a bug with the dbms_xmlgen.Convert function within Oracle 12.1 that was fixed in Oracle 12.2. Basically the function fails with XML greater than 120 KB.