10.8.4 – Operational Best Practices

Module: Section 10 – Kafka Ecosystem & Tools
Section: 10.8 – ksqlDB in Production
Goal: Production operational best practices

Monitoring

Key Metrics:

• Query processing rate
• State store size
• Rebalance frequency
• Error rate

JMX Metrics:

kafka.streams:type=stream-metrics
kafka.streams:type=stream-task-metrics

Logging

Enable debug logging:

log4j.logger.io.confluent.ksql=DEBUG

Key log files:

• ksqldb-server.log - Server logs
• ksqldb-queries.log - Query execution logs

Query Management

List queries:

SHOW QUERIES;

Terminate query:

TERMINATE query_id;

Explain query:

EXPLAIN SELECT * FROM orders EMIT CHANGES;

Troubleshooting Checklist

• Check ksqlDB server logs
• Verify Kafka connectivity
• Check state store disk space
• Monitor rebalancing frequency
• Review query execution plans

Key Takeaways

1. Monitor: JMX metrics, query rate, state size
2. Logging: Enable DEBUG for troubleshooting
3. Query Management: SHOW, TERMINATE, EXPLAIN
4. Troubleshooting: Systematic checklist

What's Next?

Next Module: 10.9 – Kafka REST Proxy