Looking for tips to load, register, index and query a huge XMLDB.

I've got 35 million highly structured XML documents, with a total size of 500 GB. An XSD is available for this data, and the end goal is to transform the data into an RDB. All fields can be considered varchar, number, or date; except maybe one or two CLOB fields. The XSD structure contains a lot of 1-n relationships, and sub-nested structures, so is quite complex.

The data has to get loaded once, and then transformed into an RDB once, so speed of update/insert queries is irrelevant. Also the speed of loading/index creation is not so important, since it only has to run once. As long as it finishes within a week or two i'm happy.