EventSourcing.Live 2021 - A system with thousands of event types

In the last 10 years we have applied event sourcing and CQRS in the development of our new ERP system. We now have almost two years of production experience. During these years we have run into interesting challenges that needed to be solved. In this session we share how we built a system with many thousands of event types, with the aim of serving thousands of companies and eventually millions of users.

Transcript

1. A system with thousands of event types Our work at AFAS Software
2. Michiel Lead Software Architect @ AFAS Software michiel.overeem@afas.nl @michielovereem https://movereem.nl Overeem
3. 500+ employees (4 locations) 12.000 customers (companies) AFAS Software 500+ employees (4 locations)
4. AFAS Profit
5. Small business and accountants AFAS SB+ 500+ employees (4 locations)
6. How do we move from Profit to SB+?
7. Person Entity Customer Role Order Agreement party Spending limit Address Organisation Entity Delivery BusinessAc tivity party Invoice BusinessAc tivity party Address Address Spending limit Spending limit Own Organisation Workarea workarea Spending limit
8. Person Entity Customer Role Order Agreement party Spending limit Address Organisation Entity Delivery BusinessAc tivity party Invoice BusinessAc tivity party Address Address Spending limit Spending limit Own Organisation Workarea workarea Spending limit • Functional model • Only suitable for ERP • Variability in the model • Contains 25 years of knowledge 22 25 96
9. Person Entity Customer Role Order Agreement party Spending limit Address Organisation Entity Delivery BusinessAc tivity party Invoice BusinessAc tivity party Address Address Spending limit Spending limit Own Organisation Workarea workarea Spending limit Generate ERP software
10. Person Entity Customer Role Order Agreement party Spending limit Address Organisation Entity Delivery BusinessAc tivity party Invoice BusinessAc tivity party Address Address Spending limit Spending limit Own Organisation Workarea workarea Spending limit
11. Data QueryModel Object StreamItem Aggregate EventHandler Projector Command Event (Nr=1) Event (Nr=2) Event (Nr=3) Query Plain and simple CQRS & event sourcing
12. StreamItem Aggregate StreamItem Aggregate StreamItem Aggregate Data QueryModel Object StreamItem Aggregate EventHandler Projector Command Event (Nr=1; Id=C) Event (Nr=1; Id=B) Event (Nr=1; Id=A) Query Event (Nr=1; Id=1) Event (Nr=1; Id=2) Event (Nr=2; Id=1) Aggregate Aggregate Aggregate StreamItem Aggregate Data QueryModel Object Data QueryModel Object EventHandler Projector Data QueryModel Object Data QueryModel Object Query Command
13. Data QueryModel Object StreamItem Aggregate EventHandler Projector Command Event (Nr=1) Event (Nr=2) Event (Nr=3) Query 3687 11646 4915 1377 1050
15. Event Store stats 34.106.336 events from 3469 event types Started with 8 customers, currently at 91 customers 0,00 5.000.000,00 10.000.000,00 15.000.000,00 20.000.000,00 25.000.000,00 30.000.000,00 35.000.000,00 40.000.000,00 Total # of events
16. Person Entity Customer Role Order Agreement party Spending limit Address Organisation Entity Delivery BusinessAc tivity party Invoice BusinessAc tivity party Address Address Spending limit Spending limit Own Organisation Workarea workarea Spending limit A change here Or here … Or here … Impact!
17. V1.1 V1.2
18. V1.1
19. V1.1 V1.2
20. V1.1 V1.2
21. V1.1 V1.2
22. V1.2
23. V1.1 V1.2 This is where the magic happens…
24. Repair/Upgrade scripts Default data Event rewrites Query StreamItem UpgradeScript Command Command StreamItem … Command
25. Some additional patterns…
26. Data QueryModel Object StreamItem Aggregate EventHandler Projector Command Event (Nr=1) Event (Nr=2) Event (Nr=3) Query StreamItem ProcessManager Event (Nr=1) Event (Nr=2) Event (Nr=3) Command EventHandler Router ProcessManagers
27. EventHandler StreamProjector Data QueryModel Object Data QueryModel Object Data QueryModel Object Query StreamItem Aggregate Command Event (Nr=1) Event (Nr=2) Event (Nr=3) Data QueryModel Object EventHandler Projector Query Event (Nr=1) Event (Nr=2) Event (Nr=3) StreamProjectors
28. Data QueryModel Object EventHandler Projector Event (Nr=1; Id=C) Event (Nr=1; Id=B) Event (Nr=1; Id=A) Query Event (Nr=1; Id=1) Event (Nr=1; Id=2) Event (Nr=2; Id=1) Data QueryModel Object Data QueryModel Object EventHandler Projector Data QueryModel Object Data QueryModel Object Query Cross-Projector-Joins
29. Data QueryModel Object EventHandler Projector Event (Nr=1; Id=C) Event (Nr=1; Id=B) Event (Nr=1; Id=A) Query Event (Nr=1; Id=1) Event (Nr=1; Id=2) Event (Nr=2; Id=1) Data QueryModel Object EventHandler Projector Data QueryModel Object Query
30. Data QueryModel Object StreamItem Aggregate EventHandler Projector Command Event (Nr=1) Event (Nr=2) Event (Nr=3) Query
31. Data QueryModel Object StreamItem Aggregate EventHandler Projector Command Event (Nr=1) Event (Nr=2) Event (Nr=3) Query Direct command results
32. Data QueryModel Object StreamItem Aggregate EventHandler Projector Command Event (Nr=1) Event (Nr=2) Event (Nr=3) Query Push notifications from projectors
33. Data QueryModel Object EventHandler Projector Event (Nr=1; Id=C) Event (Nr=1; Id=B) Event (Nr=1; Id=A) Query Data QueryModel Object EventHandler Projector Data QueryModel Object Query Timers & Projectors-on-projectors
34. Data QueryModel Object StreamItem Aggregate EventHandler Projector Command Event (Nr=1) Event (Nr=2) Event (Nr=3) Query StreamItem ProcessManager Event (Nr=1) Event (Nr=2) Event (Nr=3) Command EventHandler Router Parallel & low-priority event processing
36. Sync events
37. michiel.overeem@afas.nl @michielovereem https://movereem.nl Low-code / Impact analysis / Upgrade process / Several specific patterns Person Entity Customer Role Order Agreement party Spending limit Address Organisation Entity Delivery BusinessAc tivity party Invoice BusinessAc tivity party Address Address Spending limit Spending limit Own Organisation Workarea workarea Spending limit