Event Sourcing and CQRS with Kafka: A Complete Guide

TLDREvent sourcing is an alternative means of storing data using a log of events rather than a table. In event sourcing, you create a table and append events to it as they occur, building up your event log. Reading data in event sourcing involves combining events together at runtime to get the current state. Event sourcing can be implemented using CQRS, which segregates the write side and read side. With Kafka and ksqlDB, you can easily implement CQRS and perform streaming computation and materialize views.

Key insights

🔄Event sourcing stores data as a log of events rather than a table, allowing for easy event replay and auditability.

🔄In event sourcing, reading data involves combining events together at runtime to get the current state.

⚡️CQRS segregates the write side and read side, allowing for higher performance and event level storage.

⚡️Kafka and ksqlDB can be used to implement CQRS and perform streaming computation and materialize views.

💡Event sourcing and CQRS can be beneficial for use cases with large numbers of events and complex data processing requirements.

Q&A

What is event sourcing?

—Event sourcing is an alternative means of storing data using a log of events rather than a table. Events are appended to a table as they occur, building up an event log that represents the complete history of the data.

How does event sourcing differ from traditional data storage?

—In traditional data storage, data is stored in tables that are updated, read, and deleted. In event sourcing, data is stored as a log of events and the current state is derived by combining events together at runtime.

What is CQRS?

—CQRS stands for Command Query Responsibility Segregation. It is an architectural pattern that separates the write side and read side of an application. By segregating commands and queries, CQRS allows for higher performance and event level storage.

How can Kafka and ksqlDB be used to implement CQRS?

—Kafka and ksqlDB provide the necessary tools for implementing CQRS. Kafka acts as the event log, allowing for reliable storage of events. ksqlDB performs streaming computation and materializes views, enabling efficient read operations.

What are the benefits of using event sourcing and CQRS?

—Event sourcing and CQRS provide benefits such as easy event replay, auditability, high performance, and flexible data processing. They are especially useful for use cases with large numbers of events and complex data requirements.

Timestamped Summary

00:00Event sourcing is an alternative means of storing data using a log of events rather than a table.

00:32In event sourcing, reading data involves combining events together at runtime to get the current state.

03:35CQRS segregates the write side and read side, allowing for higher performance and event level storage.

04:08Kafka and ksqlDB can be used to implement CQRS and perform streaming computation and materialize views.

04:51Event sourcing and CQRS can be beneficial for use cases with large numbers of events and complex data processing requirements.

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