The distributed schema — plain SurrealQL, placement declared inline
DEFINE TABLE user PLACEMENT BY id; -- sharded by record id (rendezvous hash) DEFINE FIELD email ON user TYPE string UNIQUE; -- invariant → homed at hash(email) DEFINE TABLE account PLACEMENT BY id; DEFINE FIELD bal ON account TYPE number ASSERT $value >= 0; -- invariant → enforced at commit
Live coordination map — six shards, real Cloudflare regions
Query console — type any SurrealQL, watch it route & coordinate
read · local replica (1 hop, stale)
FRESH scan · all shards
FRESH scoped · only 2 shards
single write
cross-shard dependency
multi-statement (read-your-writes)
RELATE (graph edge)
graph traversal
cross-shard txn (2PC)
txn that overdraws (aborts)
MOVE (migrate)
read latency, same record two ways:
placement oracle — where does a record live?
Concurrency · rewind-replay
Two writers race the same record. The loser hits a conflict and rewind-replays locally — re-runs over the winner's value — instead of aborting. No cross-shard messages: it's one shard's own MVCC.
Concurrency · UNIQUE across regions
Two users in different regions claim the same email. Its uniqueness invariant lives at a single owner shard — both message it, it arbitrates: one GRANTED, one REJECTED. No gossip, no "assume free."