Multiplayer Collaborative Canvas · View 05 of 23 · People and journeys
Why the viewer path is separate
- A viewer never reaches the sequencer: they get a checkpoint, a log tail, and a broadcast group. One popular document can therefore carry 1,000 viewers without consuming the node that orders its edits (ADR-06).
- The cold open of a 60 MB document at p95 2.5 s is the worst latency in the whole set, and it is spent on bytes rather than coordination — which is why checkpoint cadence trades directly against it (ADR-10).
- Comment permissions are independent of edit permissions, so the commenter can write a comment and not an operation.
The trough
- The canvas renders before its assets do. Placeholder-on-pending is a deliberate choice: blocking the open until every byte has arrived would make a slow link look like a broken file (ADR-13).
- A comment whose anchor object has been deleted is marked orphaned rather than hidden — a comment that vanishes is read as censorship, not as cleanup.
Assumptions
- p50 document 1.2 MB, p99 60 MB, ceiling 500 MB.
- Viewers are three times as numerous as editors and mostly arrive on mobile.
