- identify the issue where the oid adaption was failing; basically
we have to do our own oid->adaption on a nested cursor, and we cache these adapters;
if the first value that came back for that oid is None, we were caching a null adapter.
- identify also that unfortunately psycopg2 is adapting date values with an explicit typecast
in Postgresql native format (e.g. ::timestamp, etc.) - foundationdb doesn't accept these, so we have
to do our own date coercion.  We want to do it per-connection and also without the Python object
overhead that psycopg2's system seems to require so we are doing string coercion at the
cursor.execute() level.