IN-MEMORY DATABASE CSCI 6442

WHY? Database systems were developed to manage data collections too large to be stored in main memory They provide multi-user concurrent access and recover from soft and hard crashes. Today, RAM prices have gone down, so it’s practical to store more and more in RAM In addition, growth in address spaces allows for larger in-memory databases to be addressed Hence RAM-only database systems

ALPHABET SOUP MMDB—main-memory database IMDB—in-memory database

KEY TO GROWTH OF MMDB Growth (and price drop!) of non-volatile RAM technology allows MMDBs to run at full speed and maintain data in presence of power failure

WHAT ABOUT ACID? MMDBs usually support atomicity, consistency and isolation What about the D? These mechanisms are used:  Checkpoints, when all data is written to disk  Transaction logging, that journals all transactions  Non-volatile memory

Tonight we’ll hear several presentations about MMDBs. Clearly they have a place, where extremely fast response is needed and the application is important enough to bear the cost of additional RAM