Cianplan

Level 2: Data · L2.8 Batch, streaming & change data capture

Windows, watermarks and the lakehouse

Explain event-time windows, late data and where analytics lands.

12 min · Pro

What you take away

  • Aggregate by event time — when it happened — not by processing time, or late arrivals land in the wrong bucket.

And 3 more inside the class, in Pro.

How the class is laid out

  1. The problem
  2. The simple version
  3. Deciding when to publish
  4. Where it all lands
  5. Batch vs stream
  6. The log
  7. Ordering and scaling
  8. Delivery
  9. CDC
  10. Windows
  11. Check your understanding