r the join.  The
 join operation is performed as the returned cursor is accessed.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>txn</CODE> - the transaction used to protect all operations performed with
 the cursor, or null if the operations should not be transaction
 protected.  If the store is non-transactional, null must be specified.
 For a transactional store the transaction is optional for read-only
 access and required for read-write access.<DD><CODE>config</CODE> - the cursor configuration that deter