Explore the evolution and power of User Defined Aggregate Functions (UDAFs) in Apache Spark through this 21-minute Databricks conference talk. Delve into the journey of customized scalable aggregation logic, from its initial flaws to the improved design in Spark 3.0. Learn how to create your own UDAF library, understand the inner workings of User Defined Aggregation, and discover how the latest UDAF features enhance both usability and performance. Gain insights into the Apache Spark code review process and pick up valuable tips for successfully integrating large features into the upstream community. Follow the speaker's personal experience with UDAFs, from initial challenges to ultimate triumph, while acquiring practical knowledge about this powerful feature in Apache Spark's data processing capabilities.