When trying to create anonymous data, I encountered an unexpected side effect of the updateXML statement while updating XML documents in an Oracle 10gR2 (10.2.0.1.0) EE database.
I got a small test environment in which a table (HGO010_DETAM) resides that contains approximately 500Mb of XML documents. The real production environment is much bigger, think in 100th of Gigabytes per table and an average of 512 Kb (up to 6 Mb) per document. The web application that makes use of this data is document driven so these documents were stored in an XMLType column based on CLOB storage. The table also contains an extra ID column that was added for reference purposes.
The table was created as follows: