[Monetdb-developers] Tuple reconstruction algorithm

Dear all, I'm trying to understand the tuple reconstruction algorithm in MonetDB. Maybe someone can give me a short overview to understand it or the place in documentation where I can do some research. As far as I understood, the BAT consists of object-ids and values. Is the object-identifier the same as the record- or tuple-identifier? If it so, is there a special mechanism to position a specific oid in a BAT or must it be scanned to find a oid? And if not, how can I determine the corresponding values in different BATs to reconstruct a tuple? Or am I totally wrong and there is an obvious way to reconstruct tuples from different BATs? Thanks in advance, Tim