AI engineering glossary · Data engineering
What is watermark?
Watermark: A marker in stream processing stating that the system believes no more events older than a given event time will arrive, so windows up to that time can be closed and their results emitted. It balances waiting for late data against latency.
Watermark: an example
With a 2-minute watermark delay, the 10:00 to 10:05 window is finalised once events stamped 10:07 have been seen.
Related terms
More Data engineering terms
Where you learn it
Watermark is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.