Techniques for selecting a new compression technique or altering the currently instantiated compression technique employed over a data stream in data collection system are provided. At least one change to at least one external contextual condition is detected. One or more modifications to a defined compression technique is generated, either independently or in conjunction with one or more modifications to the event processing operators that operate on the data stream and whose output provides the values that are compressed by the defined compression technique, in response to the at least one change to the at least one external contextual condition. The defined compression technique of the at least one client device is altered in accordance with the one or more modifications to form a modified compression technique through which the unmodified or processed data stream will be compressed before being sent to the server.