Full State Snapshots

[mattyg]

Store full state snapshots in DHT to reduce the workload for a new peer to get up-to-date.

struct Snapshot {
  data: Vec<u8>,
  hashes: Vec<ActionHash> // hashes of all update statevectors included
}

• On regular interval

  • Check if my agent pub key is closest to assigned key based on my timestamp (to reduce redundant snapshots)
    • get all agents associated with document, order ascending
    • get timestamp
    • calculate timestamp % number of agents
    • pick the agent at that index
    • if the agent is me, continue
  • get last snapshot + all updates since last snapshot, merge into single statevector
  • publish statevector as snapshot, specify hash of all updates included within it

• When new agent joins

  • fetch latest snapshot
  • fetch all statevectors not included in latest snapshot
  • merge latest snapsho with statevectors
  • apply to ydoc