GraphX, Pregel, and Breadth-First-Search with Pregel. Back to: Apache Spark 3 with Scala – Hands On with Big Data! Previous Lesson Exercise Solution Lesson 6 within section Intro to Spark Streaming. You must enroll in this course to access course content. Next Lesson Implementing BFS with GraphX and Pregel Lesson 2 within section Intro to GraphX. You must enroll in this course to access course content.