Experiments on the concurrent rule execution in database systems

Issues pertinent to the concurrent execution of rules in a database management system (DBMS) are studied. Rules are modeled as database transactions. As such, they should follow serializability as their correctness criterion for execution. Rule execution has the additional constraint that the rules, conditions must be true in the database for the actions that execute, and rules must fail when their conditions are not true any longer. Based on this observation, two locking-based protocols are discussed. Information on the possible conflicts between conditions and actions of rules is used to provide greater concurrent access to the relations, based on a new lock paradigm. A simulation testbed was developed in order to study the rule features and database characteristics that play an important role in the performance of concurrent production rule execution