YATA: collaborative documents and how to make them fast

Slides made for presentation with the same title, made live at Lambda Days conference in July 2022. It discusses technical details behind YATA: a conflict resolution algorithm for rich text CRDT documents used in Yrs/Yrs libraries.

Transcript

1. YATA: COLLABORATIVE DOCS AND HOW TO MAKE THEM FAST
2. INTRODUCTION Bartosz Sypytkowski @Horusiath b.sypytkowski@gmail.com bartoszsypytkowski.com
3. — When do we need CRDTs — YATA: conflict resolution for arrays and maps — Update merge & split — Optimizations AGENDA
4. YJS.DEV
5. PROBLEM STATEMENT COLLABORATIVE TEXT EDITOR
6. COLLABORATIVE TEXT EDITOR Alice a Carol a Bob a
7. COLLABORATIVE TEXT EDITOR Alice a Carol a Bob a insert(1, ‘b’) insert(1, ‘c’)
8. COLLABORATIVE TEXT EDITOR Alice a Carol ac Bob ab
9. COLLABORATIVE TEXT EDITOR Alice a Carol ac Bob ab insert(1, ‘b’) insert(1, ‘c’) insert(1, ‘b’) insert(1, ‘c’)
10. COLLABORATIVE TEXT EDITOR Alice abc Carol abc Bob acb
11. MAYBE JUST SYNCHRONIZE VIA CENTRAL SERVER?
12. SERVER-DRIVEN TEXT EDITOR Alice a Carol a Bob a server a
13. SERVER-DRIVEN TEXT EDITOR Alice a Carol a Bob a server a insert(1, ‘b’) insert(1, ‘c’)
14. SERVER-DRIVEN TEXT EDITOR Alice a Carol a Bob a server a insert(1, ‘b’) insert(1, ‘c’) insert(1, ‘b’) insert(1, ‘c’) E1 E2
15. SERVER-DRIVEN TEXT EDITOR Alice a Carol a Bob a server ab insert(1, ‘b’) insert(1, ‘b’) E2 insert(1, ‘b’)
16. SERVER-DRIVEN TEXT EDITOR Alice ab Carol ab Bob ab server acb insert(1, ‘c’) insert(1, ‘c’) insert(1, ‘c’)
17. SERVER-DRIVEN TEXT EDITOR Alice acb Carol acb Bob acb server acb
18. COMPAR ING VECTOR CLOCKS ISSUES 1. Latency 2. Online-only / Network issues 3. Characters interleaving 4. Server: bottleneck & point of failure
19. FIELDS SHARING SIMILAR PROBLEMS 1. Collaborative text editors 2. Cross-continental data replication 3. Vehicle apps 4. Remote areas 5. One-account/multi-device sync
20. CONFLICT AVOIDANCE “Let the majority decide on the correct order.” Decisions are made by quorum
21. CONFLICT AVOIDANCE CONFLICT RESOLUTION “Let the majority decide on the correct order.” “Given enough context everyone should come to the same conclusion.” Decisions are made by quorum Decisions are made individually
22. CONFLICT RESOLUTION IT’S ALL ABOUT PRESERVING THE ORIGINAL INTENT
23. SEMANTICS MATTER 1. Insert characters one after another 2. Fixing a typo 3. Move an element 4. Move a range of elements 1. Insert characters at positions X, X+1, X+2, etc. 2. Insert/remove character at position X 3. Remove an element then re-insert it 4. Delete then re-insert range of elements
24. DON’T USE INDEXES FOR POSITIONING THEIR MEANING CHANGES OVER TIME
25. LAMPORT CLOCK A:1 Unique peer ID Sequence Number
26. CONTEXT-AWARE INSERTION insert_between(A:1, B:1, (B:2, ‘b’))
27. CONTEXT-AWARE INSERTION insert_between(A:1, B:1, (B:2, ‘b’)) inserted block ID inserted block content
28. CONTEXT-AWARE INSERTION insert_between(A:1, B:1, (B:2, ‘b’)) left neighbor right neighbor inserted block ID inserted block content
29. CONFLICT RESOLUTION
30. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING CONFLICT RESOLUTION
31. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING CONFLICT RESOLUTION
32. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING CONFLICT RESOLUTION ?
33. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING CONFLICT RESOLUTION Use block IDs to skip over blocks with lower precedence
34. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING CONFLICT RESOLUTION
35. YATA FOR MAPS
36. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” JSON Document state YMap “key” A:1 ENTRY INSERTION YMAP
37. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” JSON Document state YMap “key” A:1 ENTRY INSERTION YMAP ymap.set(‘key’, ‘b’)
38. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” JSON Document state YMap “key” A:1 ENTRY INSERTION YMAP ymap.set(‘key’, ‘b’) A:2 ID A:1 LEFT NULL RIGHT CONTENT “b” JSON Create new block representing insert operation
39. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” JSON Document state YMap “key” A:2 ENTRY INSERTION YMAP ymap.set(‘key’, ‘b’) A:2 ID A:1 LEFT NULL RIGHT CONTENT “b” JSON Insert block at the end of “key”’s sequence of values
40. A:1 ID NULL LEFT NULL RIGHT CONTENT length = 1 DELETED Document state YMap “key” A:2 ENTRY INSERTION YMAP ymap.set(‘key’, ‘b’) A:2 ID A:1 LEFT NULL RIGHT CONTENT “b” JSON Tombstone all blocks for “key”’s values except the latest one
41. MOVING ELEMENTS
42. WHY DON’T JUST USE REMOVE + INSERT?
43. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING MOVING ELEMENTS
44. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING MOVING ELEMENTS doc.move(1..2, 0)
45. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING MOVING ELEMENTS doc.move(1..2, 0)
46. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING MOVING ELEMENTS doc.move(1..2, 0) A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED Create new block representing move operation
47. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING MOVING ELEMENTS doc.move(1..2, 0) A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED Range 1..2 maps onto continuous sequence of blocks from A:2 to B:2
48. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING MOVING ELEMENTS doc.move(1..2, 0) A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED Destination index 0 suggests to insert this block before A:1
49. A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING Document state B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED MOVING ELEMENTS
50. Document state MOVING ELEMENTS doc.move(1..2, 0) A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED Mark moved elements
51. HOW ARE WE GOING TO READ THAT?
52. READING MOVED ELEMENTS Document state A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED ITERATOR
53. READING MOVED ELEMENTS Document state A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED ITERATOR Move stack A:3 A:2..B:2 Move frame informs if we’re currently within moved range context
54. READING MOVED ELEMENTS Document state A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED ITERATOR Move stack A:3 A:2..B:2 Jump to the beginning of moved range
55. READING MOVED ELEMENTS Document state A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED ITERATOR Move stack A:3 A:2..B:2 “b”
56. READING MOVED ELEMENTS Document state A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED ITERATOR Move stack A:3 A:2..B:2 “b” “c”
57. READING MOVED ELEMENTS Document state A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED ITERATOR Move stack A:3 A:2..B:2 “b” “c” We reached the end of a current move frame
58. READING MOVED ELEMENTS Document state A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED ITERATOR Move stack “b” “c”
59. READING MOVED ELEMENTS Document state A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED ITERATOR Move stack “b” “c” “a”
60. READING MOVED ELEMENTS Document state A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED ITERATOR Move stack “b” “c” “a” Skip over moved blocks that aren’t part of a current move frame
61. READING MOVED ELEMENTS Document state A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED ITERATOR “b” “c” “a”
62. READING MOVED ELEMENTS Document state A:3 ID NULL LEFT A:1 RIGHT CONTENT (A:2..B:2) MOVED NULL MOVED A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING NULL MOVED A:2 ID A:1 LEFT B:1 RIGHT CONTENT “b” STRING A:3 MOVED B:2 ID A:1 LEFT B:1 RIGHT CONTENT “c” STRING A:3 MOVED B:1 ID A:1 LEFT NULL RIGHT CONTENT “d” STRING NULL MOVED ITERATOR “b” “c” “a” “d”
63. OPTIMIZATIONS 1. KNOW YOUR ENVIRONMENT
64. KNOW THE DIFFERENCE Peer to Peer Client / Server Examples Yjs/Yrs, Automerge RiakDB, AntidoteDB, DynamoDB Ops / sec. few* (related to single user activity) > 1000 ops / sec Collaborators unknown, limited control known, under full control Network / connections heterogenous, unreliable Homogenous, fairly stable Data volume fits in memory (hopefully) greater than disk
65. OPTIMIZATIONS 2. REDUCE NUMBER OF OPERATIONS
66. OPTIMIZATIONS BLOCK MERGING A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING A:2 ID A:1 LEFT NULL RIGHT CONTENT “b” STRING Document state
67. OPTIMIZATIONS BLOCK MERGING A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING A:2 ID A:1 LEFT NULL RIGHT CONTENT “b” STRING Document state Both blocks have sequential IDs
68. OPTIMIZATIONS BLOCK MERGING A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING A:2 ID A:1 LEFT NULL RIGHT CONTENT “b” STRING Document state Block was intended to be placed sequentially
69. OPTIMIZATIONS BLOCK MERGING A:1 ID NULL LEFT NULL RIGHT CONTENT “ab” STRING Document state Block A:1 is responsible for holding 2 elements now (range from A:1 to A:2)
70. OPTIMIZATIONS BLOCK MERGING A:1 ID NULL LEFT NULL RIGHT CONTENT “ab” STRING Document state A:1 ID NULL LEFT NULL RIGHT CONTENT “a” STRING A:2 ID A:1 LEFT NULL RIGHT CONTENT “b” STRING Document state These two representations are logically equivalent
71. OPTIMIZATIONS BLOCK MERGING A:1 ID NULL LEFT NULL RIGHT CONTENT “ab” STRING A:3 ID A:2 LEFT NULL RIGHT CONTENT “c” STRING Document state Next block ID = last block ID + last block length insert_between(A:2, NULL, (A:3, ‘c’))
72. OPTIMIZATIONS BLOCK MERGING A:1 ID NULL LEFT NULL RIGHT CONTENT “ab” STRING A:3 ID A:2 LEFT NULL RIGHT CONTENT “c” STRING Document state Next block ID = last block ID + last block length insert_between(A:2, NULL, (A:3, ‘c’)) Left neighbor point to last ID not block ID
73. WHAT IF WE WANT TO INSERT ELEMENT WITHIN BLOCK?
74. A:1 ID NULL LEFT NULL RIGHT CONTENT “helo” STRING A:5 ID A:3 LEFT A:4 RIGHT CONTENT “l” STRING Document state insert_between(A:3, A:4, (A:5, ‘l’)) OPTIMIZATIONS BLOCK SPLITTING
75. A:4 ID A:3 LEFT NULL RIGHT CONTENT “o” STRING A:5 ID A:3 LEFT A:4 RIGHT CONTENT “l” STRING Document state insert_between(A:3, A:4, (A:5, ‘l’)) OPTIMIZATIONS BLOCK SPLITTING A:1 ID NULL LEFT NULL RIGHT CONTENT “hel” STRING Split blocks to create space
76. A:4 ID A:3 LEFT NULL RIGHT CONTENT “o” STRING A:5 ID A:3 LEFT A:4 RIGHT CONTENT “l” STRING Document state OPTIMIZATIONS BLOCK SPLITTING A:1 ID NULL LEFT NULL RIGHT CONTENT “hel” STRING
77. OPTIMIZATIONS 3. IMPROVE BLOCK INSERTION TIME
78. PREFER SEQUENTIAL ACCESS WHENEVER POSSIBLE
79. DOCUMENT BLOCK STRUCTURE UNDER THE HOOD A B C Clients Block store A:1 A:2 A:3 B:1 B:2 C:1 C:2 C:3 Client block list Root types “name” BRANCH START Pointer to a CRDT list head
80. DOCUMENT BLOCK STRUCTURE UNDER THE HOOD A B C Clients Block store A:1 A:2 A:3 B:1 B:2 C:1 C:2 C:3 Client block list Root types “name” BRANCH START Pointer to a CRDT list head New operation is always appended to the end
81. DOCUMENT BLOCK STRUCTURE UNDER THE HOOD A B C Clients Block store A:1 A:2 A:3 B:1 B:2 C:1 C:2 C:3 Client block list Root types “name” BRANCH START Pointer to a CRDT list head Finding block by ID (e.g. C:2) is done by binary search
82. IT’S ALSO BETTER FOR SYNCHRONIZING DATA
83. DELTA REPLICATION A B C Block store A:1 A:2 A:3 B:1 B:2 C:1 C:2 C:3 Root types “name” BRANCH START A B C Block store A:1 B:1 B:2 C:1 C:2 C:3 Root types “name” BRANCH START Alice Bob
84. DELTA REPLICATION A B C Block store A:1 A:2 A:3 B:1 B:2 C:1 C:2 C:3 Root types “name” BRANCH START A B C Block store A:1 B:1 B:2 C:1 C:2 C:3 Root types “name” BRANCH START Alice Bob Bob is missing some of the updates from Alice
85. DELTA REPLICATION A B C Block store A:1 A:2 A:3 B:1 B:2 C:1 C:2 C:3 Root types “name” BRANCH START A B C Block store A:1 B:1 B:2 C:1 C:2 C:3 Root types “name” BRANCH START Alice Bob Bob creates a vector clock of his most recent updates A:2 B:3 C:4
86. DELTA REPLICATION A B C Block store A:1 A:2 A:3 B:1 B:2 C:1 C:2 C:3 Root types “name” BRANCH START A B C Block store A:1 B:1 B:2 C:1 C:2 C:3 Root types “name” BRANCH START Alice Bob Alice compares Bob’s vector clock against her own known state A:2 B:3 C:4
87. DELTA REPLICATION A B C Block store A:1 A:2 A:3 B:1 B:2 C:1 C:2 C:3 Root types “name” BRANCH START A B C Block store A:1 B:1 B:2 C:1 C:2 C:3 Root types “name” BRANCH START Alice Bob Alice produces a delta with blocks that Bob is missing A A:2 A:3
88. DELTA REPLICATION A B C Block store A:1 A:2 A:3 B:1 B:2 C:1 C:2 C:3 Root types “name” BRANCH START Block store Root types “name” BRANCH START Alice Bob Bob applies incoming updates on his side A A:2 A:3 A B C A:1 A:2 A:3 B:1 B:2 C:1 C:2 C:3
89. OPTIMIZATIONS 4. INSERTING ELEMENTS CONSECUTIVELY
90. OPTIMIZATIONS CACHING LATEST POSITION let doc = Doc::new(); let txt = doc.transact().get_text(“text”); txt.insert(&mut doc.transact(), 0, “hello”); txt.insert(&mut doc.transact(), 5, “world”);
91. MAPPING BETWEEN USER INDEX AND BLOCK ID INTRODUCES COST
92. OPTIMIZATIONS CURSORS let doc = Doc::new(); let txt = doc.transact().get_text(“text”); let mut cursor = txt.seek(0); cursor.insert(&mut doc.transact(), “hello”); cursor.insert(&mut doc.transact(), “world”);
93. SUMMARY
94. — Yjs/Yrs: https://crates.io/crates/yrs — Automerge: https://automerge.org/ — Ditto.live: https://www.ditto.live/ — RiakDB: https://riak.com/ — Amazon DynamoDB: https://aws.amazon.com/dynamodb/ — AntidoteDB: https://www.antidotedb.eu/ CRDT PROJECTS
95. — CRDTs deep dive: https://bartoszsypytkowski.com/tag/crdt/ — List of aggregated CRDT articles: https://crdt.tech — Making CRDTs faster: https://josephg.com/blog/crdts-go-brrr/ REFERENCES
96. THANK YOU