Joining Data in real time in Kafka using KSQL

Once data is in Kafka Topics, data from multiple topics can be joined in real time and the results can be published to another topic.

This is a common use case in organizations where updates to User Privileges need to sent out to multiple systems.

In a previous article, we discussed how data can be moved from PostgreSQL database to Kafka using Kafka Connect. Now, we will explore how we can join the User data in four topics that were sourced from four tables in PostgreSQL, and how the combined User update can be published to another Topic in Real Time that other Systems are listening.

Code to implement above KSQL Streams and Tables