Batch & Streaming interview questions for data engineers
Batch vs stream, event time, windows, CDC, Lambda/Kappa, ETL/ELT, and OLTP/OLAP. 23 questions with full answers, written for freshers. All topics
Core Concepts (1)
Streaming Design (14)
- Late data: drop, update or side output?
- Choosing a watermark delay
- State stores and state size
- End-to-end exactly-once
- Deduplication in streams
- Apache Beam model
- Triggers and accumulation modes
- Flink checkpoints vs savepoints
- Streaming joins: enrichment patterns
- Out-of-order events
- Real-time or batch?
- Delivery guarantees in Pub/Sub-style systems
- Streaming into a warehouse
- Streaming vs micro-batch latency and cost