The timestamp adjustment function places tuples on hold in order to adjust their time. If too many tuples are on hold, a memory shortage might occur. To achieve stable resource utilization throughout entire system, you can set a maximum number of tuples that can be kept on hold by the timestamp adjustment function.
When a new tuple is sent from the input adaptor, the timestamp adjustment function adjusts the time and checks the number of tuples that are currently being held. When the number of tuples on hold has reached the maximum value, the timestamp adjustment function stops placing any new tuples on hold and shuts down the query group. When a query group is shut down, all its tuples being held by the function are discarded.
You specify the maximum number of tuples that can be held by the timestamp adjustment function in the stream.maxKeepTupleCount parameter in the system configuration property file, query group property file, or stream property file. For details about the stream.maxKeepTupleCount parameter, see 8.6 System configuration property file (system_config.properties).