Перспективы и проблемы использования энергонезависимой памяти
At the beginning of the paper, it is demonstrated that the technology of the most widely used SQL-oriented DBMS is inextricably linked with HDD technology. Features of HDD affect the data structures and algorithms for performing operations, methods of managing the buffer pool of the DBMS, transaction management, query optimization, etc. An alternative to a disk DBMS is an in-memory DBMS, storing databases entirely in the main memory. Despite the fact that in-memory DBMS has a number of advantages over disk DBMS, at present there is practically no competition. This, first of all, is due to natural limitations on the size of databases, inherent in in-memory DBMS. At present, new types of data storage hardware have appeared: SSD – block solid-state drives and SCM – storage-class memory (non-volatile main memory). SSD characteristics made it expedient to develop a DBMS in terms of their exclusive use, but so far such a DBMS has not been created, and SSDs are used simply instead of HDDs in DBMS that do not take into account their features. The availability of SCM allows to radically simplify the architecture of the database and significantly improve their performance. To do this, you need to review many of the ideas used in disk-based databases.