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![ADD-WINS SET Alice
ADDING A VALUE
@elon/followers
Server A
Event
Log
@elon/followers
Server B
Event
Log
ADD
{ A:1 }
apply
{
“Alice”: [{A:1}]
}](https://image.slidesharecdn.com/multi-masterreplication-200212210313/85/Collaborative-eventsourcing-103-320.jpg)
![ADD-WINS SET Alice
ADDING A VALUE
@elon/followers
Server A
Event
Log
@elon/followers
Server B
Event
Log
[
“Alice”: [{A:1}]
]
{
“Alice”: [{A:1}]
}](https://image.slidesharecdn.com/multi-masterreplication-200212210313/85/Collaborative-eventsourcing-104-320.jpg)
![ADD-WINS SET
Alice
ADDING /
REMOVING
VALUE
@elon/followers
Server A
Event
Log
@elon/followers
Server B
Event
Log
[
“Alice”: [{A:1}]
]
{
“Alice”: [{A:1}]
}
unfollow(@elon)
command](https://image.slidesharecdn.com/multi-masterreplication-200212210313/85/Collaborative-eventsourcing-105-320.jpg)
![ADD-WINS SET
Alice
ADDING /
REMOVING
VALUE
@elon/followers
Server A
Event
Log
@elon/followers
Server B
Event
Log
[
“Alice”: [{A:1}]
]
{
“Alice”: [{A:1}]
}
unfollowed({A:1})
commit](https://image.slidesharecdn.com/multi-masterreplication-200212210313/85/Collaborative-eventsourcing-106-320.jpg)
![ADD-WINS SET
Alice
ADDING /
REMOVING
VALUE
@elon/followers
Server A
Event
Log
@elon/followers
Server B
Event
Log
[
“Alice”: [{A:1}]
]
{
“Alice”: [{A:1}]
}
unfollowed({A:1})
commit
REM
{ A:2 }
followed(@elon)
commit](https://image.slidesharecdn.com/multi-masterreplication-200212210313/85/Collaborative-eventsourcing-107-320.jpg)
![ADD-WINS SET
Alice
ADDING /
REMOVING
VALUE
@elon/followers
Server A
Event
Log
@elon/followers
Server B
Event
Log
[
“Alice”: [{A:1}]
]
{
“Alice”: [{A:1}]
}
E2
REM
apply
followed(@elon)
commit
{ A:2 }](https://image.slidesharecdn.com/multi-masterreplication-200212210313/85/Collaborative-eventsourcing-108-320.jpg)
![ADD-WINS SET
Alice
ADDING /
REMOVING
VALUE
@elon/followers
Server A
Event
Log
@elon/followers
Server B
Event
Log
[
“Alice”: [{A:1}]
]
{
“Alice”: [{A:1}]
}
E2
REM
apply
replicatereplicatereplicate
{ A:2 }
ADD
{ A:1,B:1 }](https://image.slidesharecdn.com/multi-masterreplication-200212210313/85/Collaborative-eventsourcing-109-320.jpg)
![ADD-WINS SET
Alice
ADDING /
REMOVING
VALUE
@elon/followers
Server A
Event
Log
@elon/followers
Server B
Event
Log
{
“Alice”: [{A:1}]
}
ADD
apply
REM
{ A:1,B:1 }
replicate
{ A:2 }](https://image.slidesharecdn.com/multi-masterreplication-200212210313/85/Collaborative-eventsourcing-110-320.jpg)
![ADD-WINS SET
Alice
ADDING /
REMOVING
VALUE
@elon/followers
Server A
Event
Log
@elon/followers
Server B
Event
Log
apply
{
“Alice”: [
{A:1},
{A:1, B1}
]
}
REM
{ A:2 }
ADD
{ A:1,B:1 }
apply](https://image.slidesharecdn.com/multi-masterreplication-200212210313/85/Collaborative-eventsourcing-111-320.jpg)
![ADD-WINS SET
Alice
ADDING /
REMOVING
VALUE
@elon/followers
Server A
Event
Log
@elon/followers
Server B
Event
Log
{
“Alice”: [
{A:1, B1}
]
}
{
“Alice”: [
{A:1, B1}
]
}](https://image.slidesharecdn.com/multi-masterreplication-200212210313/85/Collaborative-eventsourcing-112-320.jpg)
More Related Content
Similar to Collaborative eventsourcing
Collaborative eventsourcing
- 1.
- 2. INTRODUCTION Bartosz Sypytkowski ▪ @Horusiath ▪b.sypytkowski@gmail.com ▪ bartoszsypytkowski.com
- 3. Eventsourcing everywhere Popular tools and challenges Multi-master replication: motivation How to… AGENDA
- 4.
- 5. EVENTSOURCING QUICK RECALL Event stream E1E2 E3 E4 E5 E6
- 6. EVENTSOURCING QUICK RECALL Event stream E1E2 E3 E4 E5 E6 S1 Reader A T5 Reader B Writer E7
- 7. EVENTSOURCING QUICK RECALL Event stream E1E2 E3 E4 E5 E6 S1 Reader A T5 Reader B Writer E7 Sn = fold(Sn-1, En)
- 8. EVENTSOURCING 1. (Usually) onelogical writer 2. Many possible readers 3. State is constructed incrementally by applying (totally ordered) stream of events over the previous version of state 4. Asynchronous READERS & WRITERS
- 9. COMPAR ING VECTOR CLOCKS EVENTS 1. Describe factsthat already happened 2. Undeniable 3. Ordered 4. Side effect free (idempotent) 5. Consumed ≠ Deleted
- 10.
- 11. EVENTSOURCING SNAPSHOTS Event stream E1 E2E3 E4 E5 E6 S1 Reader A T5 Reader B Writer E7 Snapshot store T3
- 12. EVENTSOURCING SNAPSHOTS Event stream E1 E2E3 E4 E5 E6 S1 Reader A Reader B Writer E7 Snapshot store T3
- 13. EVENTSOURCING SNAPSHOTS Event stream E1 E2E3 E4 E5 E6 S1 Reader A Reader B Writer E7 Snapshot store T3T3
- 14. EVENTSOURCING SNAPSHOTS Event stream E1 E2E3 E4 E5 E6 S1 Reader A Writer E7 Snapshot store T3 Reader B T3
- 15. EVENTSOURCING SNAPSHOTS Event stream E1 E2E3 E4 E5 E6 S1 Reader A Writer E7 Snapshot store T3 Reader B T4
- 16. EVENTSOURCING SNAPSHOTS Event stream E1 E2E3 E4 E5 E6 S1 Reader A Writer E7 Snapshot store T3 Reader B T5
- 17. QUIZ: RELATIONS BETWEENSNAPSHOT, WRITER, READER AND EVENT STREAM?
- 18. EVENTSOURCING MULTIPLE STREAMS EventLog E1 E2 E3E4 E5 S1 Reader A T5 Reader B Writer D1 D2 D3 C1 C2 C3 C4 C5 C6 E7 E6
- 19. EVENTSOURCING SCALLING OUT TODISTRIBUTED SYSTEM
- 20. COMPAR ING VECTOR CLOCKS EVENT REPLICATION Leader E1 E2 E3 FollowerA E1 E2 E3 Follower B E1 E2 S3 S3 S2
- 21.
- 22. COMPAR ING VECTOR CLOCKS EVENTUAL CONSISTENCY Leader E1 E2 E3 FollowerA E1 E2 E3 Follower B E1 E2 read read S3 S3 S2
- 23. CAN WE EVENACHIEVE STRONG CONSISTENCY?
- 24.
- 25. COMPAR ING VECTOR CLOCKS 2-PHASE COMMIT Leader E1 E2 E3 Follower A E1E2 Follower B E1 E2 S2 S2 S2
- 26. COMPAR ING VECTOR CLOCKS 2-PHASE COMMIT Leader E1 E2 E3 FollowerA E1 E2 Follower B E1 E2 S2 S2 S2
- 27. COMPAR ING VECTOR CLOCKS 2-PHASE COMMIT Leader E1 E2 E3 FollowerA E1 E2 E3 Follower B E1 E2 S2 S2 S2 E3
- 28. COMPAR ING VECTOR CLOCKS 2-PHASE COMMIT Leader E1 E2 E3 FollowerA E1 E2 E3 Follower B E1 E2 S2 S2 S2 E3
- 29. COMPAR ING VECTOR CLOCKS 2-PHASE COMMIT Leader E1 E2 E3 FollowerA E1 E2 E3 Follower B E1 E2 S3 S3 S2 E3
- 30. COMPAR ING VECTOR CLOCKS 2-PHASE COMMIT Leader E1 E2 E3 FollowerA E1 E2 E3 Follower B E1 E2 S3 S3 S2 E3
- 31.
- 32. REPLICATED WRITE Leader E1 E2 S2 Follower E1 E2 S2 Follower E1E2 S2 Follower E1 E2 S2 Follower E1 E2 S2
- 33. REPLICATED WRITE Leader E1 E2 S2 Follower E1 E2 S2 Follower E1E2 S2 Follower E1 E2 S2 Follower E1 E2 S2 E3
- 34. REPLICATED WRITE Leader E1 E2 S2 Follower E1 E2 S2 Follower E1E2 S2 Follower E1 E2 S2 Follower E1 E2 S2 E3
- 35. REPLICATED WRITE Leader E1 E2 S3 Follower E1 E2 S2 Follower E1E2 S2 Follower E1 E2 S3 Follower E1 E2 S3 E3 E3 E3
- 36. REPLICATED READ Leader E1 E2 S3 Follower E1 E2 S2 Follower E1E2 S2 Follower E1 E2 S3 Follower E1 E2 S3 E3 E3 E3
- 37. REPLICATED READ Leader E1 E2 S3 Follower E1 E2 S2 Follower E1E2 S2 Follower E1 E2 S3 Follower E1 E2 S3 E3 E3 E3
- 38. REPLICATED READ Leader E1 E2 S3 Follower E1 E2 S3 Follower E1E2 S2 Follower E1 E2 S3 Follower E1 E2 S3 E3 E3 E3 E3
- 39. REPLICATED READ Leader E1 E2 S3 Follower E1 E2 S3 Follower E1E2 S2 Follower E1 E2 S3 Follower E1 E2 S3 E3 E3 E3 E3
- 40. CONSENSUS BASED REPLICATION 1. Latency 2. Geo-replication 3.Network partitions 4. Offline capabilities 5. Single writer bottleneck PROBLEMS AND AVOIDANCE
- 41.
- 42. CAN WE GIVEUP ON TOTAL ORDER?
- 43.
- 44. UNORDERED LOG Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch?
- 45. UNORDERED LOG Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Sam: Where are we going for lunch? Sam: Where are we going for lunch?
- 46. UNORDERED LOG Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Sam: Where are we going for lunch? Alice: Asian restaurant? Sam: Where are we going for lunch? Bob: Foodtruck?
- 47. UNORDERED LOG Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Sam: Where are we going for lunch? Alice: Asian restaurant? Sam: Where are we going for lunch? Bob: Foodtruck?
- 48. UNORDERED LOG Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Alice: Asian restaurant? Sam: Where are we going for lunch? Bob: Foodtruck?
- 49. UNORDERED LOG Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Alice: Asian restaurant? Sam: Where are we going for lunch? Bob: Foodtruck? Alice: Asian restaurant?
- 50. UNORDERED LOG Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Bob: Foodtruck? Alice: Asian restaurant? Sam: Where are we going for lunch? Alice: Asian restaurant? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck?
- 51. UNORDERED LOG Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Bob: Foodtruck? Alice: Asian restaurant? Sam: Where are we going for lunch? Alice: Asian restaurant? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck? Alice: Asian restaurant?
- 52. COMPAR ING VECTOR CLOCKS UNORDERED LOG 1. It’s hardto detect conflicts and potentially invalid states … 2. … and event harder to correct them
- 53. Sam Alice Bob Sam Alice Bob Sam:Where are we going for lunch? Bob: Foodtruck? Alice: Asian restaurant? Bob: Foodtruck? Sam: Where are we going for lunch? Alice: Asian restaurant? Sam: Where are we going for lunch? Bob: Foodtruck? Alice: Asian restaurant? CAUSALITY VIOLATION Disallowed!
- 54. ILLEGAL STATES CANHAPPEN EVEN WITHOUT TIME TRAVELING
- 55. Sam Alice Bob Sam Alice Bob Sam:Where are we going for lunch?CAUSALITY VIOLATION
- 56. Sam Alice Bob Sam Alice Bob Sam:Where are we going for lunch? Sam: Where are we going for lunch?CAUSALITY VIOLATION
- 57. Sam Alice Bob Sam Alice Bob Sam:Where are we going for lunch? Sam: Where are we going for lunch? Bob: Foodtruck? CAUSALITY VIOLATION
- 58. Sam Alice Bob Sam Alice Bob Sam:Where are we going for lunch? Bob: Foodtruck? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck? CAUSALITY VIOLATION
- 59. Sam Alice Bob Sam Alice Bob Sam:Where are we going for lunch? Bob: Foodtruck? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck? WTF? CAUSALITY VIOLATION
- 60. Sam Alice Bob Sam Alice Bob Sam:Where are we going for lunch? Bob: Foodtruck? Bob: Foodtruck? Sam: Where are we going for lunch? Sam: Where are we going for lunch? Bob: Foodtruck? CAUSALITY VIOLATION
- 61.
- 62. CAUSAL ORDER Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch?
- 63. CAUSAL ORDER Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Sam: Where are we going for lunch?
- 64. CAUSAL ORDER Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Sam: Where are we going for lunch? Bob: Foodtruck?
- 65. CAUSAL ORDER Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck?
- 66. CAUSAL ORDER Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck? Keep original sender
- 67. CAUSAL ORDER Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck?
- 68. CAUSAL ORDER Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck? Deduplicate
- 69. CAUSAL ORDER Sam Alice Bob Sam AliceBob Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck? Sam: Where are we going for lunch? Bob: Foodtruck?
- 70. COMPAR ING VECTOR CLOCKS DEDUPLICATION 1. Unique IDfor each event… 2. Timestamps for causality tracking
- 71. PROBLEM: WALL CLOCKTIME DOESN’T TELL US ANYTHING ABOUT CAUSALITY
- 72. TRACKING CAUSAL ORDER WITHVECTOR CLOCKS
- 73. VECTOR CLOCK Alice 2 Bob 3 Sam1 Unique node ID Sequence Nuber
- 74. COMPAR ING VECTOR CLOCKS CAUSAL ORDERING Equals Greater than Lessthan Concurrent A 2 B 3 C 1 A 2 B 3 C 1 A 2 B 3 C 2 A 2 B 3 C 1 A 2 B 2 C 1 A 2 B 3 C 1 A 2 B 3 C 1 A 2 B 2 C 2 = = = = = > = < = = > < Greater than A 2 B 3 C 2 A 2 B 3 C 1 = = >
- 75. VECTOR CLOCK MERGE MAX ( ,) = A 1 B 3 A 2 B 1 C 1 A 2 B 3 C 1
- 76. PEER TO PEERREPLICATION
- 77. PEER REPLICATION Alice Bob { A:2,B:1 } { A:0, B:3 } B1 B1 A1 A2 B2 B3
- 78. PEER REPLICATION Alice Bob { A:2,B:1 } { A:0, B:3 } B1 B1 A1 A2 B2 B3 Can you give me all events, which happened since { A:2, B:1 } ?
- 79. PEER REPLICATION Alice Bob { A:2,B:1 } { A:0, B:3 } B1 B1 A1 A2 B2 B3 Can you give me all events, which happened since { A:2, B:1 } ? Sure, these are the events you may be interested in. B2 B3
- 80. PEER REPLICATION Alice Bob { A:2,B:3 } { A:0, B:3 } B1 B1 A1 A2 B2 B3 Can you give me all events, which happened since { A:2, B:1 } ? Sure, these are the events you may be interested in. B2 B3 B2 B3
- 81. PEER REPLICATION Alice Bob { A:2,B:3 } { A: 0, B: 3 } B1 B1 A1 A2 B2 B3 Can you give me all events, which happened since { A:2, B:1 } ? Sure, these are the events you may be interested in. B2 B3 B2 B3 Can you give me all events, which happened since { A:0, B:3 } ?
- 82. PEER REPLICATION Alice Bob { A:2,B:3 } { A:0, B:3 } B1 B1 A1 A2 B2 B3 Can you give me all events, which happened since { A:2, B:1 } ? Sure, these are the events you may be interested in. B2 B3 B2 B3 Can you give me all events, which happened since { A:0, B:3 } ? Sam: Sure, these are the events you may be interested in. A1
- 83. PEER REPLICATION Alice Bob { A:2,B:3 } { A:1, B:3 } B1 B1 A1 A2 B2 B3 Can you give me all events, which happened since { A:2, B:1 } ? Sure, these are the events you may be interested in. B2 B3 B2 B3 Can you give me all events, which happened since { A:0, B:3 } ? A1 Sam: Sure, these are the events you may be interested in. A1
- 84. PEER REPLICATION Alice Bob { A:2,B:3 } { A:1, B:3 } B1 B1 A1 A2 B2 B3 Can you give me all events, which happened since { A:2, B:1 } ? Sure, these are the events you may be interested in. B2 B3 B2 B3 Can you give me all events, which happened since { A:0, B:3 } ? A1 Sam: Sure, these are the events you may be interested in. A1 Sure, these are the events you may be interested in. A1 A2
- 85. PEER REPLICATION Alice Bob { A:2,B:3 } { A:1, B:3 } B1 B1 A1 A2 B2 B3 Can you give me all events, which happened since { A:2, B:1 } ? Sure, these are the events you may be interested in. B2 B3 B2 B3 Can you give me all events, which happened since { A:0, B:3 } ? A1 Sam: Sure, these are the events you may be interested in. A1 Sure, these are the events you may be interested in. A1 A2 Ben: A1? I’ve seen it already.
- 86. PEER REPLICATION Alice Bob { A:2,B:3 } { A:1, B:3 } B1 B1 A1 A2 B2 B3 Can you give me all events, which happened since { A:2, B:1 } ? Sure, these are the events you may be interested in. B2 B3 B2 B3 Can you give me all events, which happened since { A:0, B:3 } ? A1 Sam: Sure, these are the events you may be interested in. A1 Sure, these are the events you may be interested in. A1 A2 A2 Ben: A1? I’ve seen it already.
- 87. { streamId: “chat/general”, version: {A:1,B:1,C:2}, origin:A, data: <user data> } STANDARDT EVENT { streamId: “chat/general”, sequenceNr: 98300211, data: <user data> } REPLICATED EVENT * both models are simplified
- 88. VERSIONING STATE INTERACTIVE MODEL(GIT-LIKE)
- 89.
- 90.
- 91. COMPAR ING VECTOR CLOCKS INTERACTIVE STATE RESOLUTION Bob S1 {A:1, B:0} S0 {A:0, B:0} commit(S2,{A:0, B:1})S2 {A:0, B:1}
- 92. COMPAR ING VECTOR CLOCKS INTERACTIVE STATE RESOLUTION S1 {A:1, B:0} S0 {A:0, B:0} S2 {A:0,B:1} pull(ALICE) Bob S2 {A:0, B:1} S1 {A:1, B:0} Manual resolution required
- 93. COMPAR ING VECTOR CLOCKS INTERACTIVE STATE RESOLUTION S1 {A:1, B:0} S0 {A:0, B:0} S2 {A:0,B:1} S2 {A:0, B:1} S1 {A:1, B:0} commit(S3, {A:1, B:2}) Bob S3 {A:1, B:2}
- 94. COMPAR ING VECTOR CLOCKS INTERACTIVE STATE RESOLUTION S1 {A:1, B:0} S0 {A:0, B:0} S2 {A:0,B:1} S2 {A:0, B:1} S1 {A:1, B:0} S3 {A:1, B:2} commit(S4, {A:2, B:0}) Alice S4 {A:2, B:0}
- 95. COMPAR ING VECTOR CLOCKS INTERACTIVE STATE RESOLUTION S1 {A:1, B:0} S0 {A:0, B:0} S2 {A:0,B:1} S2 {A:0, B:1} S1 {A:1, B:0} S3 {A:1, B:2} pull(Bob) Alice S4 {A:2, B:0} S3 {A:1, B:2} S4 {A:2, B:0}
- 96. COMPAR ING VECTOR CLOCKS INTERACTIVE STATE RESOLUTION S1 {A:1, B:0} S0 {A:0, B:0} S2 {A:0,B:1} S2 {A:0, B:1} S1 {A:1, B:0} S3 {A:1, B:2} pull(Bob) Alice S4 {A:2, B:0} S3 {A:1, B:2} S4 {A:2, B:0} Conflict S1/S2 was already resolved
- 97.
- 98. “AUTOMATIC”: IN CASEOF CONFLICT IT WILL ALWAYS PREFER ONE (AND THE SAME) OPERATION OVER ANOTHER
- 99. ADD-WINS SET Alice ADDINGA VALUE follow(@elon) command @elon/followers Server A Event Log @elon/followers Server B Event Log
- 100. ADD-WINS SET Alice ADDINGA VALUE followed(@elon) commit @elon/followers Server A Event Log @elon/followers Server B Event Log
- 101. ADD-WINS SET Alice ADDINGA VALUE followed(@elon) commit @elon/followers Server A Event Log @elon/followers Server B Event Log ADD { A:1 }
- 102. ADD-WINS SET Alice ADDINGA VALUE @elon/followers Server A Event Log @elon/followers Server B Event Log E1 { A:1 } apply replicate E1 { A:1 } apply replicate ADD { A:1 } apply replicate
- 103. ADD-WINS SET Alice ADDINGA VALUE @elon/followers Server A Event Log @elon/followers Server B Event Log ADD { A:1 } apply { “Alice”: [{A:1}] }
- 104. ADD-WINS SET Alice ADDINGA VALUE @elon/followers Server A Event Log @elon/followers Server B Event Log [ “Alice”: [{A:1}] ] { “Alice”: [{A:1}] }
- 105. ADD-WINS SET Alice ADDING / REMOVING VALUE @elon/followers ServerA Event Log @elon/followers Server B Event Log [ “Alice”: [{A:1}] ] { “Alice”: [{A:1}] } unfollow(@elon) command
- 106. ADD-WINS SET Alice ADDING / REMOVING VALUE @elon/followers ServerA Event Log @elon/followers Server B Event Log [ “Alice”: [{A:1}] ] { “Alice”: [{A:1}] } unfollowed({A:1}) commit
- 107. ADD-WINS SET Alice ADDING / REMOVING VALUE @elon/followers ServerA Event Log @elon/followers Server B Event Log [ “Alice”: [{A:1}] ] { “Alice”: [{A:1}] } unfollowed({A:1}) commit REM { A:2 } followed(@elon) commit
- 108. ADD-WINS SET Alice ADDING / REMOVING VALUE @elon/followers ServerA Event Log @elon/followers Server B Event Log [ “Alice”: [{A:1}] ] { “Alice”: [{A:1}] } E2 REM apply followed(@elon) commit { A:2 }
- 109. ADD-WINS SET Alice ADDING / REMOVING VALUE @elon/followers ServerA Event Log @elon/followers Server B Event Log [ “Alice”: [{A:1}] ] { “Alice”: [{A:1}] } E2 REM apply replicatereplicatereplicate { A:2 } ADD { A:1,B:1 }
- 110. ADD-WINS SET Alice ADDING / REMOVING VALUE @elon/followers ServerA Event Log @elon/followers Server B Event Log { “Alice”: [{A:1}] } ADD apply REM { A:1,B:1 } replicate { A:2 }
- 111. ADD-WINS SET Alice ADDING / REMOVING VALUE @elon/followers ServerA Event Log @elon/followers Server B Event Log apply { “Alice”: [ {A:1}, {A:1, B1} ] } REM { A:2 } ADD { A:1,B:1 } apply
- 112. ADD-WINS SET Alice ADDING / REMOVING VALUE @elon/followers ServerA Event Log @elon/followers Server B Event Log { “Alice”: [ {A:1, B1} ] } { “Alice”: [ {A:1, B1} ] }
- 113. NEXT STEPS… 1. How tooptimize reading events by vector clock? 2. Transactions 3. Batching and compression of events
- 114.
- 115. What eventsourcingis all about: https://martinfowler.com/eaaDev/EventSourcing.html Eventuate: http://rbmhtechnology.github.io/eventuate/ CRDTs for collaborative text editing: https://www.slideshare.net/BartoszSypytkowski1/collaborative-text- editing-132892964 REFERENCES
- 116.