Struct ReplicaApplyMetrics 

pub struct ReplicaApplyMetrics {
    pub gap_total: AtomicU64,
    pub divergence_total: AtomicU64,
    pub apply_error_total: AtomicU64,
    pub decode_error_total: AtomicU64,
    pub apply_miss_total: AtomicU64,
    pub fenced_total: AtomicU64,
    pub bytes_applied_total: AtomicU64,
    pub records_applied_total: AtomicU64,
}

PLAN.md Phase 11.5 — counters the replica apply loop bumps when an invariant breaks. Surfaced via reddb_replica_apply_errors_total. Decode errors aren’t strictly apply errors but they share the same observability lane so dashboards alert on “replica is ingesting trash from primary regardless of cause”.

Fields

gap_total: AtomicU64

divergence_total: AtomicU64

apply_error_total: AtomicU64

decode_error_total: AtomicU64

apply_miss_total: AtomicU64

Issue #814 — a delete (or other apply) that found no target on the replica: a missing collection or a missing entity. Non-fatal (the LSN chain still advances so idempotent re-pull converges, see #813), but recorded so a missed delete that drives collection-count drift leaves a trail instead of being swallowed by let _ =.

fenced_total: AtomicU64

Issue #835 — a record carrying a term behind the replica’s current term was fenced at the apply boundary (a returning ex-primary on a stale term). Fail-closed: the record is rejected and the LSN/term chain does not advance, so the deposed primary cannot move any watermark until it re-syncs under the new term.

bytes_applied_total: AtomicU64

Issue #1242 — entity-payload bytes from successfully applied WAL records (entity_bytes for insert/update, refresh payload for refresh; deletes carry no payload and contribute 0). Monotonic within one process lifetime; reset-aware for readers after restart. Surfaced via reddb_replication_apply_bytes_total.

records_applied_total: AtomicU64

Issue #1242 — count of WAL records successfully applied (Applied outcome only; Idempotent and Skipped are excluded). Monotonic within one process lifetime. Surfaced via reddb_replication_apply_records_total.

Implementations

impl ReplicaApplyMetrics

pub fn record(&self, kind: ApplyErrorKind)

pub fn snapshot(&self) -> [(ApplyErrorKind, u64); 6]

pub fn snapshot_throughput(&self) -> (u64, u64)

Issue #1242 — throughput snapshot: (bytes_applied_total, records_applied_total). Both are monotonic within a process lifetime and zero after restart, so callers that track rate must detect a reset (new value < prior value) and treat it as a restart.

Trait Implementations

impl Debug for ReplicaApplyMetrics

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

Formats the value using the given formatter.

impl Default for ReplicaApplyMetrics

fn default() -> ReplicaApplyMetrics

Returns the “default value” for a type.