Enum ClusterEvent 

pub enum ClusterEvent {
    Update {
        query_id: QueryId,
        update: Update,
    },
    Faulted {
        query_id: QueryId,
        reason: String,
        cause: FaultCause,
    },
    Progressed {
        worker: usize,
        tx_id: TxId,
    },
}

Events from a Cluster’s bounded channel. Registration emits a committed Hydrated baseline. Later Changed slices can arrive before the transaction commits. Buffer them until Progressed from the worker that hosts the query. For a combined result across workers, wait for every relevant worker.

Faulted is terminal. Discard provisional changes for that query and re-register for a fresh baseline. Derivation failures, worker loss, and rollback after speculative delivery can fault a query; no further updates follow for that registration.

Faulted lives here, not as an Update variant, because it is an out-of-band lifecycle signal, not an incremental data change — and the single-thread Db never produces it (its ordinary derive errors abort the transaction; a delta-overflow shed re-delivers Update::Hydrated instead).

Variants

Update

A query’s incremental update.

Fields

query_id: QueryId

update: Update

Faulted

A query was destroyed after a derivation fault on its worker; reason describes the underlying error and cause classifies it — a push-deadline bail must survive to the host distinguishable from an ordinary derive fault (FOLLOWER-LAG-SHED §6.6: it is shed trigger (b)). No further events arrive for this query.

Fields

query_id: QueryId

reason: String

cause: FaultCause

Progressed

Transaction tx_id committed, and worker emitted all its Changed slices before this marker on the same ordered channel. Receiving this event permits release of that worker’s buffered changes. It does not acknowledge application callbacks or downstream transport delivery.

A combined subscription waits for every relevant worker before advancing cv_min. The marker also advances queries whose results did not change.

Fields

worker: usize

tx_id: TxId

Trait Implementations

impl Clone for ClusterEvent

fn clone(&self) -> ClusterEvent

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ClusterEvent

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.