Performance Test: Flink 1.19 vs. Spark 4.0 vs. Kafka Streams 3.8 Windowed Aggregation Throughput

In high-throughput event processing, windowed aggregation is the silent killer of pipeline performance: a 2024 survey of 1,200 data engineers found 68% of production stream processing outages trace back to misconfigured or underperforming window operations. Our benchmarks of Flink 1.19, Spark 4.0, and Kafka Streams 3.8 reveal a 3.2x throughput gap between the fastest and slowest contenders under identical load, with critical tradeoffs in latency, resource efficiency, and operational overhead tha