Changelog Topic
Keep state locally and back it with a log: simple to reason about, and the reason a restart takes as long as the log is long.
-
-
Allowed Lateness
An engine that silently drops late records is not misbehaving. Keeping a window open to accept them costs state, which is why the default is to keep nothing.
-
Stream Processing Semantics and Correctness
A streaming result describes data received by an agreed boundary. See how windows, lateness, state, and publication rules make revisions understandable.
-
Log Compaction
Time-based retention forgets by age; compaction forgets by key. One keeps a recent window of events, the other keeps the latest value for everything.