MMDB partial reload

When a system failure occurs in a main memory database (MMDB) system, the primary copy of the database which resides permanently in a volatile memory is lost. Reload of the database from archive memory into main memory is needed to recover this lost copy. Several complete reload algorithms, which are used when main memory is large enough to store the entire database, have been designed for a parallel and multi-processor database environment. However, little research has been done for partial reload which is needed when only a part of the database can fit into main memory. This paper proposes three MMDB partial reload algorithms for a multi-processor main memory database system and presents their performance results with the Least Recently Used paging scheme being used to handle page faults. The simulation experiments show that reload based on frequency of data access yields the best transaction response time and system throughput.