SqlConsumers
Exports `SqlViewStore`, `SqlPolicyStore`, `SqlStreamStore`.
SqlViewStore
Kind: Primitive
A view’s durable state: its snapshot, the entries it emitted and the input
log it dedupes by. Every row is a fold of billing_event, so dropping the
table and replaying the log is always allowed.
receive drops a delivery already in the input log by (source, seq),
applies the rest through kit.apply, writes the snapshot, the entries and
the input rows in one atomic unit, then delivers downstream — so a crash
between the write and the delivery replays rather than skips.
SqlPolicyStore
Kind: Primitive
A policy’s dedupe log. A policy hears every event it is responsible for, at least once and in order per key; this row is what makes the second delivery of one event a no-op instead of a second charge.
The handler runs before the row is written, so a crash between them replays the policy — which is safe because every command it sends carries its own command id.
SqlStreamStore
Kind: Primitive
A keyed, append-only stream. A write whose origin is not after the last
applied one is a repeat and is dropped, which is what makes a stream safe to
feed from an at-least-once producer.