Consumer lag is when your Kafka consumers fall behind the messages being produced. If left unchecked, it can lead to outdated analytics, alerting delays, and even data loss in edge cases.
🛠️ How to Identify Consumer Lag
Use the CLI:
kafka-consumer-groups.sh --bootstrap-server <broker> \
--describe --group <group-name>
Check LAG column.
Solutions
- Scale up consumers.
- Optimize processing logic.
- Enable multithreaded consumption (e.g., with Kafka Streams).
- Repartition the topic for more parallelism.
- Monitor with tools like Prometheus, Burrow, or Confluent Control Center.