Events visibility vs streams visibility

In my recent implementation of a simple event sourcing library I had to make a small design choice. There are streams which should be considered private. For instance, there's a process manager position stream, which holds the position change of events already processed by process managers. Its' events should not be published to other modules, … Continue reading Events visibility vs streams visibility

Process manager in event sourcing

There is a pattern which can be used to orchestrate collaboration of different aggregates, even if they are located in different contexts/domains. This patters is called a process manager. What it does is handling events which may result in actions on different aggregates. How can one create a process manager handling events from different sources? … Continue reading Process manager in event sourcing

Optimisation of queries against event-sourced systems

I hope you're familiar with event sourcing pattern. Switching from update-this-row to a more behavioral paradigm in designing systems, that's one of the most influential trends for sure. But how, a system storing only business deltas/events can be queried? Can it be queried at all? Project your views To answer this need you can use … Continue reading Optimisation of queries against event-sourced systems