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# Let's Get Aggregated: Custom UDAFs in Spark  


- **Date:** Friday, Jul 11, 2025
- **Time:** 09:00–09:30 (30 min)
- **Room:** Stage 8
- **Event:** World Congress 2025

## Recording

[Watch recording](https://www.wearedevelopers.com/videos/1649-let-s-get-aggregated-custom-udafs-in-spark)

## Description

Tired of the same old avg() and sum() in Spark? Wish your data could tell more interesting stories? Then this talk is for you! We'll dive into the world of User-Defined Aggregation Functions (UDAFs) in Apache Spark — your secret weapon for solving those "just-one-more-metric" moments that built-ins can't handle. 
You'll learn how to build your own aggregations using Spark's type-safe Aggregator API, giving you full control, better performance, and compiler-approved confidence. We'll show you how to craft custom metrics that actually reflect your business logic. 
Whether you're wrangling massive datasets or just want to impress your coworkers with some next-level Spark wizardry, join us and level up your data game — one custom aggregation at a time! 

## Speaker

### [Nikolai Nikolaev](https://www.wearedevelopers.com/@nikolai-nikolaev)

Drive business growth by unlocking the potential of data | Connecting business and IT


## Related talks at this congress

- [Beyond AI Readiness: Scaling Data-Driven Engineering for Next-Gen Software & Infrastructure](https://www.wearedevelopers.com/events/world-congress-2025/sessions/513-beyond-ai-readiness) — Eduard, Jannis Eickenroth, Sophie Kleinke
- [From Tables to Graphs in Minutes: Supercharging Kusto Graph Analytics with AI-Powered Development](https://www.wearedevelopers.com/events/world-congress-2025/sessions/797-from-tables-to) — Prof Smoke
- [Agentic GraphRAG with MAGMA (Manifold Agency with Graph Models and Augmentation)](https://www.wearedevelopers.com/events/world-congress-2025/sessions/879-agentic-graphrag) — Andreas Kollegger
- [NVIDIA Expert Session: Best Practices and Techniques for Building Agentic and RAG applications](https://www.wearedevelopers.com/events/world-congress-2025/sessions/548-nvidia-expert) — Anshul Jindal, Ziv Ilan