Unconnected Lookup Scenario

Lets say you have 50 million records coming from the source out of which you only want to look up for some 1 million records based on some condition then at this kind of scenario go for unconnected lookup

In unconnected lookup's, its not necessary that we call it for every row. Because its unconnected, and not connected to the data flow pipeline, we can choose to call when it meets certain conditions.

This way we can use the unconnected lookup more efficiently