What is the difference between data streaming and batch processing?

Data streaming and batch processing are two approaches for handling data, differing primarily in how and when data is processed. Data streaming processes data continuously in real-time as it’s generated, enabling immediate analysis and action. Batch processing handles large volumes of data in scheduled, grouped intervals, making it suitable for tasks where latency isn’t critical. The choice between them depends on the use case’s requirements for speed, volume, and computational efficiency.

The key distinction lies in their processing models. Streaming systems, like Apache Kafka or Apache Flink, ingest and process data records as they arrive—for example, monitoring IoT sensor data to trigger alerts instantly. This requires low-latency infrastructure to manage unbounded data streams. In contrast, batch systems, such as Hadoop or Spark, process fixed datasets at rest. A classic example is generating daily sales reports from a day’s transactions. Batch jobs often run on schedules, prioritize throughput over speed, and are optimized for large-scale data transformations (e.g., aggregating terabytes of logs).

Use cases and trade-offs further differentiate the two. Streaming is ideal for real-time needs like fraud detection, live dashboards, or instant user recommendations. However, it demands robust error handling (e.g., reprocessing failed events) and state management. Batch processing excels at complex analytics on historical data, such as training machine learning models or calculating quarterly metrics. It’s simpler to debug and scales cost-effectively for large datasets but can’t deliver sub-minute results. Hybrid approaches (e.g., Lambda architectures) sometimes combine both, but modern tools like Apache Beam allow unified code for batch and streaming, reducing complexity. Developers choose based on whether immediacy or comprehensive analysis is more critical.