A two-stage data compression method for real-time database

Real-time database has been widely applied in industrial process control field, in which historical data costs vast space. In order to increase the capacity of database while keeping the characteristic of high speed, data compression technology was adopted into real-time database. This paper proposes a two-stage data compression method for historical data of real-time database, in which the first stage uses Swinging Door data compression algorithm and the second stage uses a newly designed lossless compression algorithm named LZSH. LZSH is a derivative of LZ77, the experiments indicate that this algorithm achieve small amount of computation, high compression ratio and fast compression speed.