Consumer Lag Tracking & Alerting
Learn what consumer lag means, how to measure it with built-in tools, and how to alert on it before consumers fall dangerously behind.
What Is Consumer Lag?
Consumer lag is the difference between the latest offset produced to a partition (the log-end offset) and the offset a consumer group has committed.
Lag tells you how far behind your consumers are. Rising lag means consumers can't keep up with producers.
Why Lag Matters
High lag has real consequences:
- Stale data downstream (dashboards, alerts, ML features).
- Risk of hitting retention and losing unconsumed messages.
- A signal of undersized consumers or a stuck partition.
All lessons in this course
- Command-Line Tools for Kafka
- Monitoring Kafka with JMX & Tools
- Security: Authentication & Authorization
- Consumer Lag Tracking & Alerting