What is driving port? When do you use it? Answer When you set the sorted-input parameter of "JOIN" component to "In memory: Input need not be sorted", you can find the driving port. Generally driving port use to improve performance in a graph. The driving input is the largest input. All other inputs are read into memory. For example, suppose the largest input to be joined is on the in1 port. Specify a port number of 1 as the value of the driving parameter. The component reads all other inputs to the join — for example, in0, and in2 — into memory. Default is 0, which specifies that the driving input is on port in0. Join also improves performance by loading all records from all inputs except the driving input into main memory.