Main memory database management systems have become essential for response-time-bounded applications, such as those in telecommunications systems or Internet, where users frequently access a table in order to get information or check whether an element exists, and require the response to be as fast as possible. Continuous data growth is making it unafordable to keep entire relations in memory and some commercial applications provide two different engines to handle data in-memory and on-disk separately. However, these systems assign each table to one of these engines, forcing large relations to be kept on secondary storage. In this paper we present TwinS|a hybrid database management system that allows managing hybrid tables, i.e. tables partially managed by both engines. Our objective is twofold: first, to allow large tables that do not fit in the memory to partially benefit from in-memory management techniques and, second, to provide a way to discard unnecessary accesses to both memory and disk. Overall, we show that we can reduce response time when accessing a large table in the database. All our experiments have been run on a dual-engine DBMS: IBM-SolidDB .