An in-memory database (IMDB) is a database management system( DBMS) that, unlike classic DBMS systems, uses the computer's main memory as data storage instead of hard disks. The advantage lies in the higher access speeds of the main memory, which significantly reduces access times.
Since the storage capacity ofRAM is limited by the system, grid storage provides an opportunity to extend the limits. In IMDB systems, mostly compact data sets are processed. IMDB systems are used in applications with huge data volumes such as Big Data or in data warehouses. They can be usefully employed wherever datapersistence is a concern and large volumes of data have to be stored in the shortest possible time. For example, in data backup using snapshots or in the short-term recording of changes in databases.
A further development of pure in-memory databases are hybrid databases, which use both main memory and hard disks for data storage.