Performance evaluation of two step locking protocol for location databases in mobile environment

The mobile computing paradigm introduces new technical issues in the area of database systems. In a mobile environment, the location of mobile users is a kind of system data that is referred most frequently. In mobile environments, location data are stored in databases. However, as the location of user is a frequently changing piece of data, queries on location data are prone to inconsistency. Aggregate queries are among the type of queries that will suffer greatly. In this paper, we propose the two-step locking protocol for location databases that can guarantee aggregate queries to get consistent results. We show that our proposed protocol performs much better than the conventional single-step locking protocol if used for location databases in mobile environment.