Flink Real-Time Data Development: Cases on Data Skew, Watermark Failure, and GroupBy Issues
The article walks through three Flink streaming pitfalls—data‑skew‑induced back‑pressure, lost watermarks after interval joins, and ineffective group‑by causing duplicate rows—and shows how to resolve them with two‑stage distinct aggregation, hash‑based key distribution, processing‑time windows or split jobs, and mini‑batch buffering.