Event-Driven Architecture
These articles look at event-driven systems in production. They cover how messages get processed and how a processor remembers where it stopped, what to do when events arrive out of order or more than once, and how to rebuild read models without stopping the system. Many of the recent ones use Emmett and PostgreSQL. For the basics, start with the Event Driven Architecture guide.
11 articles
![On rebuilding read models, Dead-Letter Queues and Why Letting Go is Sometimes the Answer]()
On rebuilding read models, Dead-Letter Queues and Why Letting Go is Sometimes the Answer
In the last article, I explained how to rebuild Event-Driven Read Models in a safe and resilient way. I asked readers to let me know if they…
![Rebuilding Event-Driven Read Models in a safe and resilient way]()
Rebuilding Event-Driven Read Models in a safe and resilient way
Let’s make a soup today: a blog soup. We’ll mix multiple ingredients like: events (obviously), read models, inline and async projections…
![Multi-tenancy and dynamic messaging workload distribution]()
Multi-tenancy and dynamic messaging workload distribution
There are several reasons why I’m blogging. The first one is that I forget, and writing helps me to remember and organise my findings. The…
![Checkpointing the message processing]()
Checkpointing the message processing
Let’s start by asking you two questions. What Super Frog has to do with messaging? When was the last time you wrote if statements in SQL? If…
![Consumers, projectors, reactors and all that messaging jazz in Emmett]()
Consumers, projectors, reactors and all that messaging jazz in Emmett
Did you know that you can build an event store in one hour? I even did it a few times on the conference stage. Actually, it took me usually…
![Requeuing Roulette in Event-Driven Architecture and Messaging]()
Requeuing Roulette in Event-Driven Architecture and Messaging
I’m always saying that there’s a thin line between good and bad practice, and this thin line is named “Context”. That’s also true for the…
![Handling Events Coming in an Unknown Order]()
Handling Events Coming in an Unknown Order
After the last article on Dealing with Race Conditions in Event-Driven Architecture with Read Models, I got such a question from Ben: You…
![Dealing with Race Conditions in Event-Driven Architecture with Read Models]()
Dealing with Race Conditions in Event-Driven Architecture with Read Models
My events came out of order! What should I do?! Are you familiar with the term “phantom record” and its benefits? No? Let me explain it to…
![Idempotent Command Handling]()
Idempotent Command Handling
“Is your command handling idempotent?” Sounds like a douchebag question to ask. Actually, that’s not a question but a statement that we want…
![Guide to Projections and Read Models in Event-Driven Architecture]()
Guide to Projections and Read Models in Event-Driven Architecture
If I had to choose the killer feature of Event Sourcing, I’d select projections. Why? I’ll explain that in detail in this article. Events…
![Event-driven distributed processes by example]()
Event-driven distributed processes by example
Some time ago, I wrote the general rules on processing the event-driven services. check my article Saga and Process Manager - distributed…
