a scan for this query is created and returned , as follows . first , the method materializes its rhs query . it then determines the optimal chunk size , based on the size of the materialized file and the number of available buffers . it creates a chunk plan for each chunk , saving them in a list . finally , it creates a multiscan for this list of plans , and returns that scan . concode_field_sep Transaction tx concode_elem_sep Plan lhs concode_elem_sep Schema schema concode_elem_sep Plan rhs concode_field_sep Schema schema concode_elem_sep TempTable copyRecordsFrom concode_elem_sep int blocksAccessed concode_elem_sep int distinctValues concode_elem_sep int recordsOutput