Database prerequisites (03 §6 "Isolation"): without snapshot reads, publishers, claimers and the scaler block each other.
Releases the operator's independent executor (03 §11).
Pending or DeadLettered → Discarded at once. InFlight → the cancel flag is set (03 §7, F2): the lease token is left unchanged, so the holder learns of it on its next heartbeat (≤ 30 s), stops, and acknowledges — freeing an Exclusive/Ordered key immediately. If the holder is dead, ExpireLeases discards the row when the lease runs out.
Autoscaler metric (03 §11). Claimable applies the partition rules, so a blocked Ordered key contributes
nothing; InFlight is reported separately because scalers subtract running executions from the metric. Each
count is capped (the procedure stops counting at the cap); Capped says a cap was hit.
condition null = all non-Idle keys. Returns null when !ListPartitions.
The Database transport's operator (03 §5.2). It never executes on the shared source: it mints one independent executor on first use, runs every statement there, and releases it in Close(). It opens no transaction on that executor — every operator action is a single guarded procedure call.