Main memory database systems
Thanks to powerful hardware, in-memory databases run without accessing mass memory devices, which means they handle transactions and evaluations at high speed, introducing a paradigm shift in the database market.
In-memory database management systems (DBMSs), such as Times-Ten by Oracle  and solidDB by IBM , have been around for some time. These database systems keep the entire data set in RAM, thus removing the need to swap pages between the main memory buffer and the hard disk, as is the case with legacy DBMSs. However, in-memory database systems – until now – have tended to be niche products for special applications.