When using parameterized queries, Apama recommends that you use one Scenario Service client at a time to manage parameterizations. Use of more than one client can result in undefined behavior if they both attempt to edit a parameterized instance concurrently. You can connect to any correlator in the cluster, and Apama will automatically synchronize the state of parameterized instances across the cluster. This assumes that the same query definitions have been injected into the correlators on all cluster nodes. If a node fails, you will need to connect to another correlator in the cluster.