7 Reasons why your microservices should use Event Sourcing & CQRS Event Sourcing & CQRS offers a compelling and often controversial alternative for persisting data in microservice systems environments. This alternate approach is new for most of us, and it is justified to have a healthy level of skepticism towards any shiny new and often over-hyped solution. However, what is interesting is that this is so new that even the champions and evangelists often overlook the real benefits provided by this new way of capturing and storing data. In this talk, we will look at 7 of the top reasons for using Event Sourcing & CQRS. These reasons covered go beyond the often referenced benefits, such as event stores are natural audit logs, or offering the ability to go back in history to replay past events. The primary goal of this talk is to flip your view from limited to no use of ES & CQRS to an alternate perspective of what you give up when you elect to not use it as the go-to persistence strategy.

1. 7 Reasons why your microservices should use
Event Sourcing & CQRS
Hugh McKee (@mckeeh3), Developer Advocate

2. Large and Complex Systems

3. Large and Complex Systems

4. Large and Complex Systems
Processing

5. Large and Complex Systems
Processing
Persistence

6. CQRS - Command Query Responsibility SegregationCQRS - Command Query Responsibility Segregation

7. CQRS - Command Query Responsibility Segregation
System of loosely coupled services
1. Independently deployable
2. Owns its schema
3. API only access to data

8. CQRS - Command Query Responsibility Segregation
System of loosely coupled services
1. Independently deployable
2. Owns its schema
3. API only access to data

9. CQRS - Command Query Responsibility Segregation
System of loosely coupled services
1. Independently deployable
2. Owns its schema
3. API only access to data

10. CQRS - Command Query Responsibility Segregation
System of loosely coupled services
1. Independently deployable
2. Owns its schema
3. API only access to data

11. CQRS - Command Query Responsibility Segregation

12. CQRS - Command Query Responsibility Segregation
Are you crazy?

13. 0. What is Event Sourcing & CQRS
1. Smooth transition from DDD & Event Storming to implementation
2. Reduce service coupling
3. Break the read versus write performance bottleneck
4. Elevate the concurrency barrier
5. Simplify and harden messaging
6. Eliminate service coupling
7. Graduate from the IT Nursery
7 Reasons why your microservices should use ES & CQRS

14. 0. What is Event Sourcing & CQRS
1. Smooth transition from DDD & Event Storming to implementation
2. Reduce service coupling
3. Break the read versus write performance bottleneck
4. Elevate the concurrency barrier
5. Simplify and harden messaging
6. Eliminate service coupling
7. Graduate from the IT Nursery
7 Reasons why your microservices should use ES & CQRS
0Reason

16. 1

17. 1
2

18. 1
2
3

19. 1
2
3
4

20. 1

21. 1
2

22. 1
2
3

26. 0. What is Event Sourcing & CQRS
1. Smooth transition from DDD & Event Storming to implementation
2. Reduce service coupling
3. Break the read versus write performance bottleneck
4. Elevate the concurrency barrier
5. Simplify and harden messaging
6. Eliminate service coupling
7. Graduate from the IT Nursery
7 Reasons why your microservices should use ES & CQRS
1Reason

27. Smooth transition from DDD & Event Storming to implementation

28. Domain Driven Design
Event Storming
Smooth transition from DDD & Event Storming to implementation

29. Commands & Events
Microservices
Domain Driven Design
Event Storming
Smooth transition from DDD & Event Storming to implementation

30. Commands & Events
Microservices
Domain Driven Design
Event Storming
Event Sourcing & CQRS
Smooth transition from DDD & Event Storming to implementation

31. 0. What is Event Sourcing & CQRS
1. Smooth transition from DDD & Event Storming to implementation
2. Reduce service coupling
3. Break the read versus write performance bottleneck
4. Elevate the concurrency barrier
5. Simplify and harden messaging
6. Eliminate service coupling
7. Graduate from the IT Nursery
7 Reasons why your microservices should use ES & CQRS
2Reason

32. Reduce service coupling

33. Reduce service coupling

34. Reduce service coupling

35. Reduce service coupling

36. Reduce service coupling

37. Reduce service coupling

38. Reduce service coupling

39. Reduce service coupling

40. Reduce service coupling

41. Reduce service coupling

42. Reduce service coupling

43. Reduce service coupling

44. Reduce service coupling

45. Reduce service coupling

46. Reduce service coupling

47. Reduce service coupling

48. Reduce service coupling

49. Reduce service coupling

50. Reduce service coupling

51. Reduce service coupling

52. Reduce service coupling

53. Reduce service coupling

54. 0. What is Event Sourcing & CQRS
1. Smooth transition from DDD & Event Storming to implementation
2. Reduce service coupling
3. Break the read versus write performance bottleneck
4. Elevate the concurrency barrier
5. Simplify and harden messaging
6. Eliminate service coupling
7. Graduate from the IT Nursery
7 Reasons why your microservices should use ES & CQRS
3Reason

55. Break the read versus write performance bottleneck
Optimize
Reads?
Writes

56. Optimize
Writes?
Break the read versus write performance bottleneck
Reads

57. Break the read versus write performance bottleneck

58. Break the read versus write performance bottleneck

59. Break the read versus write performance bottleneck

60. Break the read versus write performance bottleneck

61. Break the read versus write performance bottleneck

62. Break the read versus write performance bottleneck
Eventually consistent

63. 0. What is Event Sourcing & CQRS
1. Smooth transition from DDD & Event Storming to implementation
2. Reduce service coupling
3. Break the read versus write performance bottleneck
4. Elevate the concurrency barrier
5. Simplify and harden messaging
6. Eliminate service coupling
7. Graduate from the IT Nursery
7 Reasons why your microservices should use ES & CQRS
4Reason

64. Elevate the concurrency barrier

65. Elevate the concurrency barrier

66. Elevate the concurrency barrier

67. Elevate the concurrency barrier

68. Elevate the concurrency barrier

69. Elevate the concurrency barrier

70. Elevate the concurrency barrier

71. Elevate the concurrency barrier

72. Elevate the concurrency barrier

73. Elevate the concurrency barrier
Eventually consistent

74. 0. What is Event Sourcing & CQRS
1. Smooth transition from DDD & Event Storming to implementation
2. Reduce service coupling
3. Break the read versus write performance bottleneck
4. Elevate the concurrency barrier
5. Simplify and harden messaging
6. Eliminate service coupling
7. Graduate from the IT Nursery
7 Reasons why your microservices should use ES & CQRS
5Reason

75. • at-most-once
• at-least-once
• exactly-once
Semantics of delivery
(maybe-once)
(once-or-more)
(essentially-once)
Simplify and harden messaging

76. Simplify and harden messaging
At-least-once
Push

77. Simplify and harden messaging
At-most-once
Push

78. Simplify and harden messaging
At-least-once
Pull

79. Simplify and harden messaging
At-least-once
Pull

80. Simplify and harden messaging
At-least-once
Pull

81. 0. What is Event Sourcing & CQRS
1. Smooth transition from DDD & Event Storming to implementation
2. Reduce service coupling
3. Break the read versus write performance bottleneck
4. Elevate the concurrency barrier
5. Simplify and harden messaging
6. Eliminate service coupling
7. Graduate from the IT Nursery
7 Reasons why your microservices should use ES & CQRS
6Reason

82. Eliminate service coupling

83. Eliminate service coupling

84. Eliminate service coupling

85. Eliminate service coupling

86. Eliminate service coupling

87. Eliminate service coupling

88. Eliminate service coupling

89. Eliminate service coupling

90. 7 Reasons why your microservices should use ES & CQRS
7
0. What is Event Sourcing & CQRS
1. Smooth transition from DDD & Event Storming to implementation
2. Reduce service coupling
3. Break the read versus write performance bottleneck
4. Elevate the concurrency barrier
5. Simplify and harden messaging
6. Eliminate service coupling
7. Graduate from the IT Nursery
Reason

91. Graduate from the IT Nursery
Reduce
Governance
Reduce
Ceremony
and
Ritual
Increase
Velocity

92. Graduate from the IT Nursery
Reduce
Governance
Reduce
Ceremony
and
Ritual
Increase
Velocity

93. Graduate from the IT Nursery
Reduce
Governance
Reduce
Ceremony
and
Ritual
Increase
Velocity
Organized Chaos

94. Graduate from the IT Nursery
Reduce
Governance
Reduce
Ceremony
and
Ritual
Increase
Velocity
Organized Revolution

95. Graduate from the IT Nursery
Reduce
Governance
Reduce
Ceremony
and
Ritual
Increase
Velocity
People are very open-minded about new things
- as long as they're exactly like the old ones.
-Charles F. Kettering

96. 7 Reasons why your microservices should use ES & CQRS
0. What is Event Sourcing & CQRS
1. Smooth transition from DDD & Event Storming to implementation
2. Reduce service coupling
3. Break the read versus write performance bottleneck
4. Elevate the concurrency barrier
5. Simplify and harden messaging
6. Eliminate service coupling
7. Graduate from the IT Nursery

97. Hugh McKee (@mckeeh3), Developer Advocate
7 Reasons why your microservices should use
Event Sourcing & CQRS