Flow Debugger (design 2026-09-05 §7.1): FlowDebugRunMethodCommand / FlowDebugRunValueChangeCommand /
FlowDebugReplayCommand on the per-node ManagementActor (Deployer role; the two run commands
are long-running), all delegating to FlowDebugRunner. RunMethod refuses on a standby with
STANDBY_NODE (ManagementCommandException now carries an optional Code that replaces
COMMAND_FAILED), validates parameters through the real ParameterValidator/SchemaRefResolver
(made public), synthesizes the inbound row (actor = operator, Extra.source = flow-debugger)
and runs the method through InboundScriptExecutor with a trace-sink RouteHelper so the reply
carries the RouteCall row + the site's inline events. RunValueChange does a traced routed
write via IInstanceRouter, then polls IPullTraceEventsClient (interface moved to Commons so
ManagementService can consume it) until a ScriptRun parented to the root settles, else
NO_TRIGGER_WITHIN_WINDOW. Replay reads IAuditLogRepository.GetTraceEventsAsync.
Claude-Session: https://claude.ai/code/session_01GSLkkHKz9JrAtmJjmQK3cP
Flow Debugger (design 2026-09-05 §5.2): bit NOT NULL DEFAULT 0 column + EF migration
20260906034113 with its docs/plans/sql production twin. CreateApiMethodCommand gains
TraceAllCalls=false; UpdateApiMethodCommand gains bool? TraceAllCalls (null = unchanged so an
older CLI never resets it). Management result echoes the flag; CLI create/update expose
--trace-all-calls; README carries the ~7-rows-per-call warning.
Claude-Session: https://claude.ai/code/session_01GSLkkHKz9JrAtmJjmQK3cP
Live + Replay modes (no dry run); entry points = inbound API method and
value-change trigger; data-sourced value-change does a real tag write with a
30 s trace arm on the instance actor for echo correlation; gated trace rows in
a new ScriptTrace audit channel (RouteCall always-on); inline step return on
RouteToCallResponse for Live; Deployer gates the page and Live run.
Claude-Session: https://claude.ai/code/session_01NcMG6xXdsJbmD2wYAgkK29
The 2026-06-26 design kept the key env-only. The file is now an explicit fallback: SCADABRIDGE_API_KEY (non-blank) -> ScadaBridge:ApiKey (non-blank, trimmed) -> not configured. Env-only stays the recommended production posture; the failure message names both sources.
Claude-Session: https://claude.ai/code/session_013L3XdmVii9i5sY4FChU8pB
Row 104: docker/vacuum-site-localdb.sh stops both nodes of a pair together, sets
auto_vacuum=INCREMENTAL + VACUUM on each node volume with integrity_check before/after,
then starts both (DRY_RUN=1 reports). Run on all three rig pairs: six files 0 -> 2, ok,
~11% smaller; site-a replication reconnected with backlog 0 and no watermark change —
VACUUM is replication-invisible (ledger keys by declared PK, oplog seq is INTEGER PRIMARY
KEY AUTOINCREMENT). Topology guide gains the recipe.
Row 105: SiteLocalDbReplicatedTableFkGuardTests builds the real site schema via OnReady
(unreplicated config so 0.3.3's own guard cannot mask the culprit) and asserts every
SiteLocalDbSetup.ReplicatedTables entry (now internal) exists and has no inbound
CASCADE/SET NULL/SET DEFAULT foreign key, with a negative control. The constraint is
enforced at build instead of at the first replicated boot.
Row 106 (found during 104's live verification, NOT caused by it — the identical 127k-row
full snapshot also landed at the earlier deploy restart): SnapshotStreamer.SendAsync stamps
as_of_seq = MAX(seq), which is 0 once a converged sender's oplog is ack-pruned to empty;
a zero-watermark receiver (rebuilt node) is never lifted, so the empty-oplog horizon rule
re-streams a full snapshot on every reconnect. Sender-side one-line fix for LocalDb 0.3.4:
as_of_seq = max(MAX(seq), last_acked_seq).
P5-3: add IX_Notifications_Created_NotificationId (CreatedAt DESC,
NotificationId DESC) — the Central UI Notification Outbox list page sorts on
exactly that pair, but no existing index leads unconditionally on CreatedAt,
so an unfiltered/lightly filtered page fell back to a full clustered-index
scan + sort on every COUNT + page request. Mirrors the Medium wave's
IX_SiteCalls_Created_TrackedOperationId migration + SQL twin pattern
faithfully, including the handwritten docs/plans/sql script.
P5-4: operator Retry/Discard was read-check-write keyed on NotificationId
only — a detached PipeTo task interleaving with the dispatcher's own write
(or a second concurrent operator action) could land between the read and
the write and get silently clobbered by the unconditional UpdateAsync,
stamping a Delivered row Discarded with stale fields. Adds
INotificationOutboxRepository.TryUpdateFromParkedAsync, a single-statement
compare-and-swap (WHERE Status == Parked) mirroring
SecuredWriteRepository.TryMarkApprovedAsync's CAS shape. NotificationOutboxActor's
RetryAsync/DiscardAsync now use the CAS write and, on a lost race, re-read
to report "notification already progressed to <Status>" instead of silently
overwriting whatever is there now.
Proof of failure: reverting only the actor's CAS usage while keeping the
repository addition reproduces the silent-overwrite bug — 7 tests fail,
including two new deterministic (non-sleep) race-proof tests that mock the
exact GetByIdAsync -> lost-CAS -> re-read sequence the finding describes.
P5-3 is perf-only; verified via migration/SQL-twin parity instead (no
runtime proof-of-failure is meaningful for an index).
P5-1: AuditLogIngestActor.OnCachedTelemetryAsync's per-entry fallback loop
(used when the cached-telemetry batch fast path fails) ran with no
budget/cancellation, unlike OnIngestAsync's fallback. A slow/wedged DB could
freeze the central ingest singleton's mailbox for minutes. The loop now runs
under its own fresh IngestFallbackBudget CancellationTokenSource (mirroring
OnIngestAsync), passes the token into BeginTransactionAsync/
InsertIfNotExistsAsync/UpsertAsync, and stops early on budget exhaustion,
logging how many entries were left for the periodic reconciliation pull to
pick up.
P5-2: SiteCallAuditRepository.QueryAsync ordered by
(CreatedAtUtc DESC, TrackedOperationId DESC) with no index leading
unconditionally on CreatedAtUtc, forcing a full scan+sort on an unfiltered
page. Added IX_SiteCalls_Created_TrackedOperationId (migration
AddSiteCallsListSortIndex + matching hand-written production-parity script
under docs/plans/sql/). Also switched the query from FromSqlInterpolated
(which binds string filters as nvarchar(4000)) to FromSqlRaw with explicitly
SqlDbType.VarChar-typed parameters, matching the SiteCalls columns'
IsUnicode(false) declaration and the write path's existing Param(...)
pattern, so seeks — including the keyset predicate — are no longer blocked
by an implicit conversion.
Tests: new AuditLogIngestActorCombinedTelemetryTests case proves the
fallback budget bounds the wait (hanging repo stub, ~5s not indefinite),
that remaining entries are skipped, and that a non-default/cancellable
token reaches the repository call; verified fail-unfixed by reverting the
actor change (test times out at its 20s bound). Existing
SiteCallAuditRepositoryTests QueryAsync/keyset/stuck-cutoff cases (real
MSSQL) confirm the raw-SQL rewrite still returns correct pages.
The WP-4 runs measured the stream path only up to the bounded send channel;
the probe deliberately substituted the socket hop with a controllable reader,
which is exactly where the R2 SiteStreamEventBatcher lives — so batching had
never been in any benchmark's hot path. The harness now also attaches per-site
wire probes: a real Kestrel h2c listener hosting the production
SiteStreamGrpcServer, dialed by the production SiteStreamGrpcClient with
batching negotiated, batch sizes read from the production batch_size histogram
via a MeterListener (--wire-probes-per-site, default 10; 0 restores the old
shape). Full-scale run (10x500x75, 20-min window, results doc §8 + raw JSON):
899,807 events in 12,462 frames (mean 72.2 ev/frame, p50=p99=75), wire P99
43.4 ms vs the 250 ms budget — every batch pays the full 25 ms linger since a
75-event burst never hits the 100 cap — zero drops, zero faults, offered load
100.0% of nominal with fan-out doubled. CI smoke Fact now asserts the wire
path carries traffic and observes frames.
The gauge test polls baseline+1, but the process-global gauge's baseline is
captured once: a parallel class's streams closing after capture lowers the
gauge below baseline+1 forever. Survey confirmed only SiteStreamGrpcServerTests
and CleanupVerificationTests drive the real SubscribeInstance handler that
moves the counter; both now share the SiteStreamSubscriberGauge collection
(row-96 pattern). 4/4 full-suite runs green, durations unchanged.
Row 79 executed its own prescribed remedy without waiting for a second
corruption: all ten rig data dirs (8 docker/ nodes + 2 docker-env2/ site
nodes) move from virtiofs bind mounts to named docker volumes
(scadabridge-<node>-data), seeded in place with both rigs stopped and
live-verified (site-a localDbReplicationConnected=true / backlog 0 over
the migrated files; env2 stable, 0 restarts). The feared inspectability
loss is moot — OrbStack exposes volumes at ~/OrbStack/docker/volumes/.
The rebuild surfaced latent env2 drift (pre-Secrets-0.6.2 image): env2
now carries the x-secrets-store-env posture + central data volumes.
Row 93's silent maintenance trap is now loud: SiteEventsSchemaCalibrationTests
pins the site_events columns/indexes the EventLogPurgeService size model is
calibrated against, failing with a pointer to the memo §4 recalibration on
any schema drift. Rows 92 (accepted by design) and 94 (standing tripwire)
annotated accordingly.
ReadStoreSnapshotAsync's snapshot is read off the actor thread and consumed only
when its piped message lands. Row 101 guarded the DEFINITIONS half of that race;
the CONFIG half was left to machinery whose reach is time-limited, and both legs
of the instance reconcile sweep were reachable through it:
- Row-72 leg: a read dispatched before a deploy's persist, landing after the
deploy completed AND after the pipeline released ownership, carries the
revision the deploy replaced. TryRestartStaleInstance then "repairs" the
instance BACKWARD, re-deploying the snapshot's own superseded ConfigJson.
InstanceIsOwnedByADeployPipeline covers only in-flight deploys, and the
per-revision claim has never seen the old revision, so nothing stopped it.
- Row-78 leg: a read dispatched before a delete/disable commits still shows an
enabled row while the actor is already stopped, so StartStoredInstance
resurrects it — and delete clears _sweepAttemptedRevisions, freeing the claim.
Both verified real by neutralising the freshness check and re-running the new
tests (the fail-before site event literally reads "running revision rev-2 is
stale, applying stored revision rev-1"; the deleted instance came back).
_definitionsWriteGeneration becomes _storeWriteGeneration, covering both tables
(the snapshot is one consistent read and is discarded whole, so one counter is
the right shape); DefinitionsGenerationAtRead -> StoreGenerationAtRead on both
internal records. The generation is now bumped at BOTH ends of every mutation —
when the off-thread write is dispatched and when its completion message lands —
because the config paths advance actor state before the write, so an
initiation-only bump would let an in-window read look fresh. Disable, delete and
the init-failure rollback have no actor-thread completion message of their own,
so a minimal StoreWriteCompleted self-message carries the bump for them.
CDC-replicated writes, snapshot resyncs, restored files and
SiteReconciliationActor's fetch deliberately do NOT bump: discovering exactly
those is the sweep's reason to exist.
A stale sweep result is now dropped WHOLE (no overlay apply, no start, no
restart). A stale boot load cannot be dropped — startup must finish — so it
re-dispatches LoadDeployedConfigs(); a fifth consecutive superseded read is
applied anyway with a Warning, and a late one arriving after the boot completed
is dropped rather than looping against the S5 retry timer.
Tests: three fail-before regressions (backward restart, resurrection, boot
re-read) plus two guard twins pinning that the legitimate row-72 restart and
row-78 start still fire on a current-generation snapshot. The row-101
definitions tests keep passing; FreshEmptySweepSnapshot's hardcoded generation
moves 1 -> 2 now that one artifact apply bumps at both ends.
Docs: Component-SiteRuntime.md's stale-snapshot paragraph now describes the
whole snapshot (both halves, both consumers, the boot re-dispatch, the
CDC-no-bump rule), the components mirror follows, and the arbitration memo gains
§11 extending §10 to the config half.
An off-thread snapshot read racing an artifact apply could land after the
apply populated the overlay; its stale absences then tombstoned and stopped
just-applied LIVE connections, which nothing re-creates until an instance
redeploy (the removal evicts the hash slot the overlay push is gated on).
Each read now captures a definitions-write generation at dispatch; a stale
result is discarded whole (additions too — a stale row would reconfigure a
live connection backward). Deterministic repro fails before the fix; a
fresh-generation guard test pins that row-90 disappearance still fires.
`DataConnectionManagerActor.HandleCreateConnection` is create-only (warns and
returns for a name it already holds), so `EnsureDclConnection`'s documented
"a changed config re-issues the create so the DCL adopts it" was never true on
ANY node: a corrected endpoint/credential/backup/failover-count took effect only
when the connection was next built from scratch (node restart, singleton
failover, remove-then-re-add), while the DM's hash cache recorded it as applied.
Rows 89/90 made that honest with a Warning; this closes it.
New `ReconfigureConnectionCommand` (Commons, same shape as the create):
- `DeploymentManagerActor.EnsureDclConnection` now has three outcomes off its one
per-name hash slot — unchanged -> nothing at all, new -> create, CHANGED ->
reconfigure — and logs "Reconfigured DCL connection {Connection}
(protocol={Protocol}) in place" at Information in place of the old Warning. The
winner-resolution / arbitration / tombstone logic is untouched; only what
happens after a change is detected changed.
- `DataConnectionManagerActor` FORWARDS the command to the owning connection
actor, falling back to a create for a name it does not hold, so the command is
safe whatever the manager's state.
- `DataConnectionActor` handles it in ALL THREE states and never stashes it — a
connection pointed at a wrong or dead endpoint lives in Connecting/Reconnecting,
which is exactly when a correction arrives; stashed it would wait on the broken
configuration forever. Handling replaces protocol/primary/backup/failover-count,
re-arms endpoint selection to Primary (the new config's primary is the intent,
whatever the old config had failed over to), and calls the new shared
`SwapAdapter` helper — now used by both failover sites too, so the swap exists
once: unhook + fire-and-forget dispose -> _factory.Create -> rewire -> bump
_adapterGeneration LAST. `BecomeReconnecting(afterReconfigure: true)` then
reconnects immediately (StartSingleTimer replaces any armed reconnect, so no
racing attempts) with the unstable-disconnect accounting and failover check
suppressed — the link was dropped on purpose, and counting it as an unstable
cycle could trip a failover onto the NEW backup before the new primary had been
tried once. ReSubscribeAll/ReSubscribeAllAlarms then re-issue everything from
the untouched subscription registries. Idempotent: a reconfigure carrying the
configuration already in force is a no-op.
Stop-and-recreate was rejected as destructive: subscriptions live inside
DataConnectionActor and InstanceActor cancels its subscribe-retry timer on first
success, so a rebuilt actor would have no subscribers and nothing would ever
re-subscribe.
Tests: new DataConnectionReconfigureTests (7; 5 fail / 2 pass against a
behavioural revert). DclConnectionArbitrationTests gains two row-97 tests and its
CDC-arrival test now asserts the second push is a reconfigure; its ping-pong
guard also asserts zero reconfigures, since a flip would now show up there.
SiteRuntime-010 renamed to ..._ReissuesReconfigureCommand. 3 fail against a
reverted EnsureDclConnection. DataConnectionLayer.Tests 327/327,
SiteRuntime.Tests 643/643, solution build 0 warnings.
Docs: Component-DataConnectionLayer.md gains an "In-place reconfiguration"
section under Endpoint Redundancy; Component-SiteRuntime.md, and the
docs/components/ mirrors, updated; the arbitration decision memo gains an
appended §9 postscript resolving its residual 1 (residuals 2 and 3 stay open).
Joseph Doherty