The Challenges of Event-Driven Microservices with Change Data Capture

Event Driven Architecture abstract representation

In the modern landscape of application architecture, it’s almost impossible to imagine a system without microservices. More so, Event-Driven Microservices have become the norm, where domain services publish events — essentially business facts — for downstream services to consume and react. However, the implementation of such services often encounters a well-known challenge: data consistency across the service’s own database and the event broker.

One of the most prevalent anti-patterns in this context is the Dual Fork Write pattern. Here, services attempt to write data both to their local database and to the event broker simultaneously.

Dual Fork Write Anti Pattern

This approach, while straightforward, can quickly lead to data consistency issues due to failures in writing to one of these destinations. A better solution is needed, and this is where Change Data Capture (CDC) comes into play.

Understanding Change Data Capture (CDC)

The core idea behind CDC is simple: allow domain services to operate as usual, persisting data to their own database. Instead of directly publishing events to the…