In this paper we study issues pertinent to the concurrent execution of rules in a DBMS system. We model rules as database tmnsactions. As such, they should follow serializability as their correctness criterion for execution. Rule execution has the additional constmint that their conditions must be true in the database for the actions to 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 pamdigm. A simulation testbed was developed in order to study the rule features and database chamcteristics that play an important role in the performance of concurrent production rule execution.