MonetDB Is an open-source column-oriented RDBMS
MonetDB excessively uses main memory for processing, but does not require that all data fit in the available physical memory. To handle a dataset that exceeds the available physical memory, MonetDB does not (only) rely on the available swap space, but (also) uses memory-mapped files to exploit disk storage beyond the swap space as virtual memory.
ray2501: I write tclmonetdb to research MonetDB. It works for me but I think it is not suitable for production environment.