When a query has no parameters, a single instance of the query is automatically created when the query is loaded into a correlator. This instance looks for match sets in all of this query's partitions. If one or more parameters are defined for a query, when the query is loaded into a correlator, no instances are created until a set of parameter values is specified. Apama's Scenario Service then creates an instance of that query using the specified parameter values and that instance is referred to as a parameterization.