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
. In-memory databases are more expensive than DBMS systems with hard disk drives
dueto the cost of
RAM.However, as RAM costs fall, in-memory technology will become more common.
Since the storage capacity of main memory is limited by the system, grid
storage provides an opportunity toextend the limits. In IMDB systems mostly compact data sets are processed. IMDB systems are used in applications with huge amounts of data such as Big Data or in data warehouses. They can be useful wherever data persistence is a concern and large amounts of data need to be stored in a short period of time
. A further development of pure in-memory databases are hybrid databases, which use both main memory and hard disks for data storage.