As the name specifies, lazy evaluation in Apache Spark means that the execution will not start until an action is triggered. In Spark, the lazy evaluation comes into action when Spark transformations occur. Transformations are lazy. When a transformation such as a map() is called on an RDD, it is not performed instantly. Transformations in Spark are not evaluated until you perform an action, which aids in optimizing the overall data processing workflow, known as lazy evaluation. So we can say that in lazy evaluation, data is not loaded until it is necessary.
