Adds three KPI tiles to the central Health dashboard for the Audit channel:
volume (rows in the last hour), error rate (Failed/Parked/Discarded over
total), and backlog (sum of SiteAuditBacklog.PendingCount across all sites).
Repo + service:
- IAuditLogRepository.GetKpiSnapshotAsync(window, nowUtc) — single aggregate
SELECT over the trailing window returning total + error counts; nowUtc is
optional for production callers and pinned by integration tests against the
shared MSSQL fixture so the global counts are deterministic.
- AuditLogQueryService.GetKpiSnapshotAsync() — composes the repo aggregate
with a sum of SiteAuditBacklog.PendingCount read from ICentralHealthAggregator.
- AuditLogKpiSnapshot record in Commons/Types/.
UI:
- New AuditKpiTiles Blazor component (Components/Health/) — three Bootstrap
card-tiles, click navigates to /audit/log with the matching pre-filter.
- Health.razor wires the tiles in alongside the existing Notification Outbox
KPIs; LoadAuditKpis() runs on every 10s refresh tick and degrades to em
dashes + inline error if the query fails.
- AuditLogPage extended to parse ?status= so the error-rate tile drill-in
(?status=Failed) auto-loads the grid.
Tests:
- AuditLogRepositoryTests: GetKpiSnapshotAsync mixed-status + empty-window
cases against the MSSQL migration fixture.
- AuditLogQueryServiceTests: forwarding + backlog composition; sites with
null SiteAuditBacklog contribute zero.
- AuditKpiTilesTests: 9 bUnit tests covering tile render, error-rate maths
with safe zero-events handling, em-dash unavailable path, click-through
navigation, and warning/danger border thresholds.
- HealthPageTests: new Renders_AuditKpiTiles_WithValues plus IAuditLogQueryService
stub registration in the constructor so existing outbox tests still pass.
- AuditLogPageScaffoldTests: ?status=Failed auto-load + unknown status drop.
Central singleton (M6-T4 Bundle C) that drives the daily AuditLog partition
purge. On a configurable timer (default 24 hours) the actor:
1. Queries IAuditLogRepository.GetPartitionBoundariesOlderThanAsync for
monthly boundaries whose latest OccurredAtUtc is older than
DateTime.UtcNow - AuditLogOptions.RetentionDays.
2. For each eligible boundary calls SwitchOutPartitionAsync, which runs
the drop-and-rebuild dance around UX_AuditLog_EventId.
3. Publishes AuditLogPurgedEvent(boundary, rowsDeleted, durationMs) on
the actor-system EventStream so the Bundle E central health collector
and ops surfaces can subscribe without coupling to this actor.
Co-changes:
* SwitchOutPartitionAsync returns long (rows deleted) — sampled BEFORE the
switch via COUNT_BIG over the per-partition filter so the count
reflects what the switch removed, not a post-purge scan of a table that
no longer exists. All stub implementations updated.
* AuditLogPurgeOptions: IntervalHours (default 24), IntervalOverride for
tests, Interval property resolving either.
* AuditLogPurgedEvent: record with MonthBoundary, RowsDeleted, DurationMs.
Behavior:
* Continue-on-error per boundary — one partition that throws does NOT
abandon the rest of the tick.
* DI scope opened per tick (IAuditLogRepository is a SCOPED EF Core
service); mirrors SiteAuditReconciliationActor and AuditLogIngestActor.
* SupervisorStrategy Resume keeps the singleton alive across leaked
exceptions.
* EventStream capture BEFORE the first await — Context is unsafe after
await in async receive handlers (same pattern as Sender-capture in
AuditLogIngestActor.OnIngestAsync).
Tests:
* Tick_Fires_OnDailyInterval — visible timer side effect.
* Tick_OldPartitions_SwitchedOut — both seeded boundaries purged.
* Tick_NewerPartitions_Untouched — empty enumerator → no switches.
* Tick_PublishesPurgedEvent_WithRowCount — AuditLogPurgedEvent carries
RowsDeleted and DurationMs.
* Tick_SwitchThrows_OtherPartitionsStillProcessed — continue-on-error.
* Threshold_UsesAuditLogOptionsRetentionDays — non-default 30-day window
computed from UtcNow - RetentionDays.
* EndToEnd_RealPartition_RowsRemoved_PurgedEventPublished — TestKit +
MsSqlMigrationFixture: real partitioned table, Jan-2026 row purged,
Apr-2026 row kept, AuditLogPurgedEvent observed via probe.
Replaces M1's NotSupportedException stub with the production drop-DROP-INDEX
→ CREATE-staging → SWITCH PARTITION → DROP-staging → CREATE-INDEX dance
documented in alog.md §4. UX_AuditLog_EventId is intentionally non-aligned
with ps_AuditLog_Month so single-column EventId uniqueness can be enforced
cheaply for InsertIfNotExistsAsync; SQL Server rejects ALTER TABLE SWITCH
while a non-aligned unique index is present, so the implementation drops
it, switches the partition data into a GUID-suffixed staging table on
[PRIMARY], drops staging (discarding the rows), and rebuilds the unique
index — all inside an explicit transaction with a CATCH that guarantees
the unique index is rebuilt regardless of failure point.
Also adds GetPartitionBoundariesOlderThanAsync to IAuditLogRepository: a
CROSS APPLY over sys.partition_range_values + per-partition MAX(OccurredAtUtc)
to enumerate retention-eligible months for the M6 purge actor (next commit).
Tests verify:
* Old partition's rows are removed; other months untouched
* UX_AuditLog_EventId is rebuilt after a successful switch
* InsertIfNotExistsAsync's first-write-wins idempotency still holds after switch
* On engineered SWITCH failure (inbound FK from a probe table), SqlException
propagates AND UX_AuditLog_EventId is still present (CATCH branch ran)
* GetPartitionBoundariesOlderThanAsync returns only boundaries whose partition's
MAX(OccurredAtUtc) is strictly older than the threshold; empty partitions
excluded
