Gate record: docs/plans/2026-07-20-localdb-phase2-live-gate.md.
Checks 1, 2, 5, 6 pass. Checks 3 and 4 are NOT satisfied — the defect they
were meant to confirm turned out to be the opposite of what the plan assumed.
Three defects crash-looped every driver node before check 1 could even run:
1. An empty ServerHistorian:ApiKey kills the host. ServerHistorianOptions-
Validator exists to turn exactly that class of failure into a named
OptionsValidationException, but its documented fail tier explicitly excluded
ApiKey on the reasoning that a keyless client "degrades — the gateway rejects
calls". It does not: the client validates its own options at construction, so
the process dies during Akka startup and never makes a call.
2. UseTls disagreeing with the endpoint scheme kills the host too, in both
directions (both messages confirmed in the shipped client assembly). Moving an
endpoint from https to http without clearing UseTls is an ordinary migration
slip.
3. Plaintext h2c was UNREACHABLE. HistorianGatewayClientAdapter forwarded the
TLS-only options unconditionally, and AllowUntrustedServerCertificate defaults
to false, so it always sent RequireCertificateValidation=true — which the
client rejects outright when UseTls=false. Every http:// deployment crashed,
though the scheme is documented as the supported way to select h2c, and the
only workaround was to assert a certificate posture for a connection that has
no certificate.
The fourth was the blocker, and it is Phase 2's own:
4. The drain gate deferred to a Primary that cannot deliver. Redundancy roles are
elected CLUSTER-WIDE; the alarm queue is PAIR-LOCAL. On the rig the elected
driver Primary is central-1 — it carries the driver Akka role, replicates
nobody's LocalDb and does not even run the alarm historian — so every driver
node logged "Historian drain suspended", including the two site-b nodes that
have no peer at all. Nothing drained anywhere, where before Phase 2 it drained
fine. The cost is not a duplicate; it is the buffer growing to the capacity
wall and evicting the audit trail it exists to protect.
Fixed in three layers: a separate ShouldDrainAlarmHistory policy (unknown role
drains; the two gates now deliberately disagree, and a test pins that); peer-
host matching in DriverHostActor so a node stands down only for a Primary
holding its rows; and AddAlarmHistorian short-circuiting the gate when
replication is unconfigured — testing BOTH Replication:PeerAddress and
SyncListenPort, since only the dialing half sets the former while both halves
share the queue.
Every one of these follows from the asymmetry: a false allow costs a duplicate
row, which at-least-once delivery already accepts and payload-hash ids
collapse; a false deny loses data silently.
A third vacuous test, caught by the same delete-the-guard discipline: the
role-view tests stayed green with the guard removed, because AwaitAssert polls
until an assertion passes and the assertion was "reads open" — which is the
SEEDED value, satisfied at the first poll before the actor processed anything.
They now assert the sequence of published values through a recording view; the
control then goes red for exactly the cases that matter.
Migration evidence: 11 legacy rows across two deliberately overlapping files
converged to exactly 9 identical rows on both nodes, proving D-6's payload-hash
identity on real nodes rather than in a fixture.
Open design fork, recorded in the gate doc rather than decided here: a pair
cannot currently identify its own Primary, so both halves drain. Safe in every
topology — nothing loses data — but the gate's de-duplication benefit is
unrealised until roles are scoped per pair.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Moves the alarm store-and-forward buffer out of its own alarm-historian.db
and into the node's consolidated LocalDb, where it replicates to the
redundant pair peer. A node that dies holding undelivered alarm history no
longer takes it to the grave.
Tasks 2 and 3 land together, as the plan anticipated. They are not separable:
the gate is a constructor argument of the rewritten sink, and a commit that
replicated the queue without gating the drain would be a commit in which both
nodes of a pair deliver every alarm event, continuously.
That drain gate is the load-bearing part of the change, and the recon
explains why it is new work rather than a refinement. Exactly-once delivery
across a pair is enforced today on the ENQUEUE side, by
HistorianAdapterActor: only the Primary enqueues, so the Secondary's queue is
empty and its ungated drain has nothing to send. Replicating the table
destroys that invariant.
The gate is a Func<bool> the caller supplies, because the drain runs on a
timer the sink owns rather than on a mailbox, and Core.AlarmHistorian cannot
reference PrimaryGatePolicy in Runtime. Runtime supplies it via a new
IRedundancyRoleView singleton that DriverHostActor publishes its Primary-gate
verdict to -- the same verdict the inbound-write and native-ack gates use, so
there is no second notion of am-I-the-Primary to drift.
Two failure modes are deliberately closed:
- The view is seeded OPEN, matching the policy's own answer for an unknown
role with no driver peer. A deployment that runs no redundancy never
publishes to it, and defaulting closed would silently stop its alarm
history forever.
- A gate that throws is read as not-now, never as permission, and a closed
gate reports the new HistorianDrainState.NotPrimary rather than Idle. A
Secondary's rising queue is supposed to look different from a stalled
drain, and if BOTH nodes report NotPrimary the pair is misconfigured and
says so instead of quietly filling toward the capacity ceiling.
Row ids are a hash of the payload rather than fresh GUIDs. Both adapters
accept the same fanned transition in the window before the first redundancy
snapshot arrives, and under last-writer-wins an equal key converges those two
accepts into one row instead of duplicating them.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Wave B of Batch 4 — the runtime binding seam for the dual namespace.
Applier (both realms, explicit realm at every sink call site):
- MaterialiseRawSubtree: Raw containers as folders + Raw tags as variables
keyed by RawPath (native-alarm tag → single Part 9 condition at the RawPath),
all in AddressSpaceRealm.Raw; historian tagname = override else RawPath.
- MaterialiseUnsReferences: each UNS reference Variable under its equipment
folder (Uns realm) + an Organizes UNS->Raw edge; inherits writable/array/
historian tagname from the backing raw tag (both NodeIds -> one tagname).
- FeedHistorizedRefs / ProvisionHistorizedTags now source RAW tags (mux ref
stays single, keyed by RawPath); ApplyPureRemove tears down raw tags + UNS
refs in place (raw-container removal falls back to rebuild).
DriverHostActor (dual-NodeId, single-source fan-out):
- _nodeIdByDriverRef value gains a realm (NodeRealmRef); rebuilt from
RawTags UNION UnsReferenceVariables so one (DriverInstanceId, RawPath) fans
to the raw NodeId AND every referencing UNS NodeId with identical
value/quality/timestamp. Write inverse map keyed by the bare id; the
ns-qualified NodeId the write hook passes is normalised (BareNodeId) so a
write to either NodeId resolves the same driver ref (-> RawPath write).
- Native raw alarm condition routing is realm-tagged (Raw); AttributeValueUpdate
+ AlarmStateUpdate carry the realm through to the sink.
Retire EquipmentNodeIds -> V3NodeIds.Uns (applier/VirtualTagHostActor) and
RawPaths.Combine (DiscoveredNodeMapper, discovered nodes are Raw now).
DeploymentArtifact.ParseComposition emits the Raw + UNS subtrees byte-parity
with the composer (reconstruct entities -> AddressSpaceComposer.Compose).
Sink surface: removed the transitional `= AddressSpaceRealm.Uns` defaults from
IOpcUaAddressSpaceSink / ISurgicalAddressSpaceSink / SdkAddressSpaceSink /
DeferredAddressSpaceSink / NullOpcUaAddressSpaceSink — every call site is now
explicit (realm reordered before the trailing optionals on EnsureVariable +
MaterialiseAlarmCondition). Node-manager convenience methods keep their
defaults (they are not the interface impl; Sdk delegates explicitly).
Tests: rewrote DriverHostActorLiveValueTests (fan-out drift, 1:N) +
DriverHostActorWriteRoutingTests (dual-NodeId raw/uns write routing) to the v3
raw+uns model; new AddressSpaceApplierRawUnsTests; migrated the EquipmentTags
provisioning/feed tests to RawTags; swept EquipmentNodeIds test callers.
Claude-Session: https://claude.ai/code/session_01LVneM3eh1UtJxEisFXgmox
Four continuous-historization types (IHistorizationOutbox, HistorizationOutboxEntry,
IHistorianValueWriter/HistorizationValue, HistorizationCommitMode) drifted into a
ZB.MOM.WW.OtOpcUa.Core.Abstractions.Historian sub-namespace while the other six files
in the same folder correctly use the root namespace. This violated decision #59's
flat-public-surface rule and left InterfaceIndependenceTests.AllPublicTypes_LiveInRootNamespace
red on master (pre-existing, predates round-2 remediation).
Move all four to the root namespace and drop/retarget the now-redundant
'using ...Core.Abstractions.Historian;' in the ~11 consumers. No behavioral change.
Verified: Core.Abstractions.Tests 129/129 (was 128/129), Runtime.Tests Historian+DI 72/72,
Gateway driver unit 102/102, full solution build 0 errors.
PR #423 shipped GatewayTagProvisioner + unit tests but never registered it in
DI nor passed it into the AddressSpaceApplier, so deploying historized tags used
the no-op NullHistorianProvisioning and never called the gateway's EnsureTags
(confirmed live on wonder-app-vd03: zero EnsureTags calls on a historized deploy).
Addresses HISTORIAN-GATEWAY-INTEGRATION-ISSUES.md.
Issue 1 (wire provisioner):
- Runtime: AddHistorianProvisioning extension (gated on ServerHistorian:Enabled,
mirrors AddServerHistorian) + NullHistorianProvisioning TryAdd default in
AddOtOpcUaRuntime; WithOtOpcUaRuntimeActors resolves IHistorianProvisioning and
passes it into the applier.
- Gateway driver: GatewayHistorian.CreateProvisioner factory (mirrors CreateDataSource).
- Host: Program.cs calls AddHistorianProvisioning after AddServerHistorian.
- Tests: AddHistorianProvisioningTests (config-gated registration + the
register->resolve->applier->EnsureTags chain).
Issue 2 (observability): AddressSpaceApplier logs the provisioning tally on every
successful dispatch (was gated behind Failed/Skipped > 0), including dispatched=N
so a dispatched=N/requested=0 line flags the dormant no-op. +2 tests.
Issue 3 (30s HistoryRead on unprovisioned tags): root coupling fixed by Issue 1;
documented the CallTimeout knob + coupling. Default left at 30s pending the
multi-data-point investigation the issue requests (lowering risks truncating
legitimate large reads).
Issue 4 (docs): docs/Historian.md gains a "Tag auto-provisioning (EnsureTags)"
section and CLAUDE.md a wiring/gating note (both stress ServerHistorian:Enabled).
Sibling scadaproj/CLAUDE.md carries no false claim -> unchanged.
Pre-existing Serilog observation: anchor CWD to AppContext.BaseDirectory before
AddZbSerilog so the relative file sink stops landing in C:\Windows\System32 under
the Windows-service CWD.
Builds 0-error; Runtime.Tests 355, OpcUaServer.Tests 329, Gateway.Tests 99 (+4
live-skipped) all green.
Code review found a residual silent-data-loss path: a single driver ref (mux
ref) can back SEVERAL historized equipment tags via aliasing (identical machines
sharing a register — DriverHostActor._nodeIdByDriverRef is a HashSet), each with
its own HistorianTagname. The muxRef->single-name map collapsed last-wins, so
under alias + divergent overrides only one historian tag got the value and the
rest were silently dropped — the exact failure class FU-3 exists to eliminate.
Model the fan as muxRef -> HashSet<historianName> and append ONE outbox entry per
name in OnValueChangedAsync (a per-name append failure drops only that name and
continues). Convergence removes/adds each (muxRef, name) pair individually from
the per-ref set, dropping the mux key only when its last name is removed — so
removing one alias leaves the shared ref fanning for the others with no mux churn.
Tests: aliased-refs-each-get-the-value (one fan → both historian names written),
removing-one-alias-keeps-the-ref-registered, and the override-rename test now
feeds a value post-rename to prove the write target actually moved to the new
name. Runtime 350/0, OpcUaServer 327/0; 0 warnings.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
The continuous-historization recorder conflated two identifiers into one string:
the dependency mux fans DependencyValueChanged keyed by the driver FullName
(the mux ref), but a value must be historized under the resolved historian name
(HistorianTagname override, else FullName). In the common no-override case the
two are equal, so it worked; with an override they diverge and the recorder
registered mux interest under a key the mux never fans — that tag's values were
never captured (and, had they been, would have been written under the mux ref).
Carry BOTH identifiers through the seam: a new HistorizedTagRef(MuxRef,
HistorianName) record on IHistorizedTagSubscriptionSink. The applier resolves
MuxRef = FullName and HistorianName = override-or-FullName. The recorder now
keeps a muxRef->historianName map: it registers/filters mux interest by MuxRef
but writes the outbox entry (and drains) under HistorianName. The convergence
handler re-registers the mux only when the registered key-set changes, so an
override-only rename (same FullName) updates the write target without mux churn.
Tests: a divergent-override recorder test (interest by mux ref, value written
under the override name, never the mux ref) + an override-rename no-churn test;
the applier feed tests now assert the full (mux ref, historian name) pairs.
Runtime 348/0, OpcUaServer 327/0; 0 warnings. Closes FU-3.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
The MaxAttempts<=0 warning branch in AlarmHistorianOptions.Validate() was the
only one without a test (the sibling DrainIntervalSeconds/Capacity/
DeadLetterRetentionDays warnings are covered). Add the matching case. Closes FU-4.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
The ContinuousHistorizationRecorder was spawned with an EMPTY historized-ref
set, so it registered interest in nothing and historized nothing. This feeds it
the currently-historized tag refs on every address-space deploy/redeploy so its
DependencyMuxActor interest converges to exactly the historized set (the same
refs the EnsureTags provisioning hook resolves: override-or-FullName).
Design — delta convergence (the plan is a pure DIFF):
- New seam IHistorizedTagSubscriptionSink (Core.Abstractions/Historian) with a
Null no-op singleton, mirroring how IHistorianProvisioning decouples the T15
hook. AddressSpaceApplier gains a DEFAULTED ctor param (Null sink) so all ~80
existing call sites + the production site compile unchanged.
- Apply() only ever sees a plan diff (an incremental/surgical apply carries a
delta, not the full set), so the applier feeds an add/remove DELTA computed
from AddedEquipmentTags / RemovedEquipmentTags / ChangedEquipmentTags. The
recorder keeps the full set and re-registers it. The feed is a single
non-blocking Tell behind the sink, wrapped in try/catch so a faulting feed
never blocks or breaks a deploy (same discipline as the provisioning hook).
- Recorder.UpdateHistorizedRefs(added, removed) converges the tracked set, then
— only when it actually changed — sends ONE RegisterInterest with the full set
(the mux's RegisterInterest is a full-REPLACE) or one UnregisterInterest when
it drains to empty (the mux has no per-ref unregister). An unchanged delta is
a no-op (no mux churn).
- DI: the recorder is now spawned BEFORE the applier so the adapter
(ActorHistorizedTagSubscriptionSink) can wrap its IActorRef; the Null sink is
used when continuous historization is off/unwired.
Tests: recorder convergence (add-from-empty, add+remove converge, idempotent,
drain-to-empty unregisters); applier feeds resolved added refs, removed+renamed
deltas, and survives a throwing sink. Build clean (0 warnings on touched
projects); Runtime/OpcUaServer/Gateway/AdminUI suites green.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
The HistorianGateway driver is now the sole historian read/write+alarm backend, so the
Wonderware sidecar projects are dead code. Removes the 5 Wonderware projects (driver,
.Client, .Client.Contracts, + their 2 test projects) from the solution and tree, and fully
retires the vestigial 'Historian.Wonderware' driver type (UI/probe-only; it had no driver
factory): the Host probe registration, the AdminUI driver-config surface (driver page,
tag-config editor/model/validator entry, address picker/builder, driver-type catalog +
dropdown + edit-router entries), and their tests. Prunes the now-unused Wonderware
connection fields (Host/Port/UseTls/ServerCertThumbprint/SharedSecret) from
AlarmHistorianOptions (keeping Enabled + the SQLite store-and-forward knobs) and refreshes
the stale XML docs that named Wonderware as the production backend.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
Bind ContinuousHistorizationOptions (Enabled/OutboxPath/CommitMode/
CommitIntervalMs/DrainBatchSize/DrainIntervalSeconds/Capacity/backoff) with a
warn-only Validate(); gated on Enabled AND the ServerHistorian gateway being
configured, the Host registers the durable FasterLogHistorizationOutbox (container
-disposed) + a gateway-backed GatewayHistorianValueWriter, and binds outbox
depth/dropped observable gauges on the central scraped meter. WithOtOpcUaRuntimeActors
spawns the recorder (over the same dependency-mux ref) when the options + writer +
outbox resolve, registering ContinuousHistorizationRecorderKey. Spawned with an EMPTY
historized-ref set: the deployed address space builds later, so ref population is a
documented follow-on (a later SetHistorizedRefs feed) — T18 wires the actor + outbox
+ writer + meters; the ref feed is the known remaining gap.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
I-1: Wrap the OnValueChangedAsync AppendAsync in try/catch so a durable-boundary
failure (e.g. a PerEntry fsync hitting disk-full/I-O error) can no longer propagate
out of the handler and trip Akka supervision into a restart loop. A canceled append
during shutdown returns quietly; any other exception increments a new
_outboxAppendFailures counter, logs a Warning (exception type name only), and drops
the value without recording it or nudging the drain. The counter is surfaced on
RecorderStatus (new OutboxAppendFailures field).
I-2: Strengthen Writer_failure_keeps_entry_for_retry to prove the drain actually ran
— assert the writer was invoked (the fake records even on Succeed=false) AND the
outbox stayed at 1 (RemoveAsync not called), via AwaitAssertAsync.
M-3: Capture Sender before the await in the GetStatus handler, then Tell the reply.
M-4: Add Retry_after_writer_failure_eventually_acks proving the retry -> success ->
ack path; FakeValueWriter gains a FailFirstN option + CallCount (Succeed behaviour
unchanged). Short minBackoff keeps it fast and deterministic (AwaitAssert, no sleep).
M-5: Deregister mux interest on PostStop via DependencyMuxActor.UnregisterInterest,
mirroring VirtualTagActor.PostStop, closing the dead-letter window before Terminated.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
Continuous-historization engine for non-Galaxy driver tags. Registers
interest with the per-node DependencyMuxActor for the historized refs and
taps the VirtualTagActor.DependencyValueChanged values the mux fans:
coerce to numeric -> append to the durable IHistorizationOutbox (crash
boundary) -> off-thread drain writes batches through IHistorianValueWriter
and acks (FIFO-truncates) on success, backing off (exponential, capped) on
failure. Non-numeric values are dropped + metered (SQL analog path is
numeric-only).
- New seam IHistorianValueWriter + HistorizationValue in Core.Abstractions
so Runtime stays free of the gRPC driver.
- GatewayHistorianValueWriter (driver) adapts IHistorianGatewayClient.
WriteLiveValues: HistorizationValue -> HistorianLiveValue proto, WriteAck
Success||Queued -> true; non-throwing (errors -> false for retry).
- Drain runs via PipeTo(Self) so the mailbox never blocks on the gateway
write; appends awaited on the actor thread to stay serialized.
Adaptation vs plan: the mux fans DependencyValueChanged (TagId/Value/
TimestampUtc, no quality), not DriverInstanceActor.AttributeValuePublished,
so values are recorded Good-quality (192) by the same convention the
scripted-alarm host uses.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
Addresses Task 9 review: add the enabled+nonpositive MaxTieClusterOverfetch warning
test; update the AddServerHistorian XML doc to describe the gateway-backed data source
(the alarm-path Wonderware doc stays until T13).
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
HistorianAdapterActor now subscribes to the redundancy-state DPS topic,
caches the local node's RedundancyRole, and SKIPS the durable-sink enqueue
when the local node is Secondary or Detached. Unknown/null role default-writes
so single-node deploys and the boot window never silently drop historization.
GetStatus stays ungated.
PREMISE: verified the actor is registered but FED BY NOTHING in production —
there is no AlarmHistorianEvent producer and nothing resolves its registry key
to Tell it. This is a FORWARD-LOOKING / DEFENSIVE guard, not a fix for a live
double-write: the moment a per-node feeder lands (engine -> historian, expected
as a per-node cluster broadcast like the alerts topic), only the Primary will
write to the durable sink (exactly-once across all alarm sources).
Mirrors the sibling A1 treatment of ScriptedAlarmHostActor (06c4155) and
OpcUaPublishActor's redundancy-state handler. localNode threaded through
HistorianAdapterActor.Props from ServiceCollectionExtensions (roleInfo.LocalNode).
Joseph Doherty