From WAL to Kafka: Turning Postgres Changes into Event Streams
04 Jun 2026 · Seattle Postgres · Seattle, WA
How PostgreSQL logical replication and the Debezium connector turn row-level database changes into Kafka event streams via Change Data Capture.
I gave this talk at the Seattle Postgres meetup in June 2026. Using a fictitious scenario where the audience and myself are software engineers at a fictitious AI company with a fictitious AI agent (Anthropix and Clyde), we learned how Postgres logical replication, together with replication slots and the Debezium connector, turn row-level changes into Kafka event streams via Change Data Capture – and how CDC can power downstream operations at Anthropix as it scales.
It also covered the key configuration on both the Postgres and connector sides, common use cases, monitoring replication lag and WAL growth, and the production performance tradeoffs.
Something that really bothered me when learning about the write ahead log was that I couldn’t outright read the log entries in human words instead of bytes. So this talk also included a demo of how to decode the WAL to JSON in real time, visualize each row level change, then that row level change as an event in Kafka.
The video isn’t uploaded yet, but you can check out other Seattle Postgres talks on the SEAPUG YouTube channel.
Demo code
- postgres-cdc-kafka-demo →
The demo from the talk. It uses the wal2json output plugin to emit row-level changes.
Thank you
- Jeremy Schneider · Organizer
Thank you for encouraging me to speak on this topic, and for teaching me about the WAL!