TimeAverage2/Total2: the interval the data ends inside with no non-Bad time
before its last sample (comms-loss recovery, a single sample) answers that
sample's value (Total2 0), Uncertain + Partial, instead of Bad/BadNoData —
as the SDK. Parity datasets RecoveryEnds, OutageLast, BoolSwitch with
documented masks; ProcessedConformance's reverse TA/Total mask narrowed to
the later-edge-sample interval. Docs: report-by-exception consequence,
outage-last and Boolean differences; CLAUDE.md historian bullet.
TimeAverage/Total: Uncertain when a Bad value is skipped, an Uncertain value
is used, the value is extrapolated or the interval is not covered; an
interval wholly inside an outage bridges (Uncertain); Total integrates only
the covered part. TimeAverage2/Total2 stop at the end of the data (Partial,
then BadNoData). PercentGood/PercentBad become duration-based and move to
the time-weighted family (now subject to MaxTimeWeightedRawRows). Reverse
reads set Partial on the interval holding the latest sample when nothing
follows (SDK m_startOfData). Parity tests gain end-of-data and outage
datasets; pre-existing #680 masks removed.
Live gate A1 (docker-dev, opc-plc restart / SIGINT / kill): the fast path never fired —
a real process stop delivers no session status; the keep-alives report
BadSecureChannelClosed (0x80860000) once, then BadConnectionClosed (0x80AE0000)
interleaved with BadNoCommunication for the whole outage.
Reproduced in-process with TcpStallProxy.HardClose (reset every connection, refuse new
ones; server and session alive behind it): the identical sequence, and the SDK 1.5.378
session never opens a new connection on its own (48 s with the proxy accepting again,
zero attempts) — a closed channel cannot recover in place.
The driver now treats BadSecureChannelClosed/BadConnectionClosed as definitive on the
SECOND closed-channel keep-alive failure in one outage (a good keep-alive resets the
count), raising ConnectionLost ~1 keep-alive after the drop. BadNoCommunication /
BadRequestTimeout / BadNotConnected (stall/pause) stay with the watchdog; the stall test
still sees no ConnectionLost. New wire test (hard close + reopen ⇒ raised once, SDK never
reconnects, reinit brings the identical value back Good) and unit tests (sustained raises
once; a single blip that recovers does not) — all red on the previous code. Docs updated.
F1: the SDK applies its m_startOfData Partial rule to forward reads only; ours
now does too (AggregateEvaluator.EvaluateAll + TimeWeightedAggregator). New
reverse late-start parity tests through the SDK oracle (unit) and real SQL
(conformance, both backends).
F2: AggregateEvaluator.NeedsEarliestSample — the earliest-sample query runs
only for forward reads of aggregates other than Average, and is bounded by
the window end (SqlServer < @end, QuestDB ts < $2).
F3: per-sample SDK parity extended to Range, Start, End, Delta, Min/Max
ActualTime and PercentGood/Bad (oracle maps StatusAggregateCalculator);
pre-existing definitional differences masked and marked #680.
Docs: Historian.md Partial/SDK-parity sections, CLAUDE.md bullet.
1. A per-ref delivery counter (bumped under the delivery lock by every publish path) is
captured before the trailing read is issued; a ref delivered to since is skipped.
Without source timestamps the read's sample could not be ordered against a notification
that landed mid-read, and publishing it regressed the node. Test injects the
notification inside the mocked read, with and without a read source time (red before).
2. Delivery-lock comment corrected (it serialises across subscriptions, which the SDK
dispatches on separate workers); PublishCommsLoss now publishes under the lock too.
3. CancelSessionWork cancels without disposing, so a keep-alive thread reading the old
token cannot hit ObjectDisposedException.
- HistoryUpdate Primary gate now reads IHistoryUpdateRoleView (PrimaryGatePolicy.ShouldServeHistoryUpdate):
the data-plane verdict but CLOSED until this node's first redundancy snapshot, so both pair nodes cannot
accept in the pre-join boot window. Single nodes open on their own singleton's first snapshot; admin-only
nodes register no view => no gate. DriverHostActor publishes it at every Primary-verdict publish point.
- SqlServer v1: the updater throws NotSupportedException on every arm; the node manager maps it to a
node-level BadHistoryOperationUnsupported (was per-item under a Good node for UpdateData/DeleteAtTime).
HistoryWrite bit still advertised on v1 (not knowable at materialise time) — documented.
- The update plan is evaluated before the Primary gate: an unservable request (Remove, IsDeleteModified,
not historized, no updater) is BadHistoryOperationUnsupported off-Primary, not BadInvalidState.
- Local-kind SourceTimestamp converted to UTC before the future-skew compare and sent as UTC.
- Hosted-service wiring extracted to BuildHistoryUpdatePosture and tested (gate source, skew, clock).
- Docs: Historian.md (boot window, ordering, node-level v1, HistoryWrite bit), CLAUDE.md.
Co-Authored-By: Claude <noreply@anthropic.com>
- IHistorianDataSource.SupportsReverseEvents (default false; SqlServer/QuestDB true; Gateway/Null declare false).
The node manager checks it BEFORE calling the source: an end-only capped events read becomes reverse only on
a supporting backend (Gateway, the default, keeps the pre-#675 forward [MinValue, EndTime) paging), and an
explicit reverse read on a non-supporting backend is BadHistoryOperationUnsupported without a call.
- Removed the broad catch (NotSupportedException) in the events path: a NotSupportedException from inside a
backend is now logged as a backend fault (Error), not an 'unsupported' Warning.
- Null declares the reverse overload itself; guard test: every production IHistorianDataSource declares both
the reverse overload and the capability (positive-control scan of all four backends).
- Conformance: capability reported + oversized reverse tie cluster (forward over-fetch reversed == reverse
read order; capped reverse read stopping inside the cluster flags truncation) on SqlServer + QuestDB.
- docs/Historian.md: end-only capped events read is backward on SqlServer/QuestDB, forward on Gateway.
1. RewriteEndpointUrl keeps the advertised port when the configured URL names none
(Uri.Port -1 would have sent the session to 4840); port-less + IPv6 tests.
2. The trailing re-read repairs any (value, status) difference that is not older than
the last delivered value — Good->Bad/Uncertain included; a read without a source
timestamp counts as newer; an equal source time with different content is published
(repairs the replay guard's by-design equal-timestamp drop).
3. One driver-wide delivery lock makes decide+publish atomic across live notifications,
the recovery read and the trailing read, so an older value can never land after a
newer one (deterministic race test via a seam).
4. Known gap documented: a ConnectionLost raised while the host is not Connected is
swallowed and that session falls back to the watchdog.
5. Only a SERVER-reported subscription loss raises ConnectionLost; the publishing-stall
heuristic stays with the #527 watchdog.
6. Post-recovery timers run on Task.Delay(…, Clock, ct) with a session-work CTS
cancelled on session release and dispose.
7. Replay summary at Information only when something was dropped (Debug otherwise);
a re-arm reports the superseded window's drops and counts afresh.
8. DriverInstanceActor: AttachHostStatusSource doc comment restored; Reconnecting
swallows a stray DisconnectObserved (test).
9. Stall wire test: 120 s session timeout, 3000-cycle subscription lifetime, one further
bad keep-alive tick, 60 s headroom on the post-recovery waits (5/5 green).
- Endpoint rewrite: the driver now connects to the configured host AND port (scheme
match, advertised path kept) instead of the server-advertised URL — fixes NAT/port-map
upstreams and lets an in-test proxy carry the session (SDK SelectEndpoint rule).
- TcpStallProxy + OpcUaClientDriverStallWireTests: the in-place blip (#670) is now
wire-tested on loopback — one Bad, frozen read stamp, same session, identical value
republished Good, a post-recovery change arrives, no source-time regression after
the SDK's late backlog flush.
- Defect found by that test, fixed: a change published right after a stall rode a
Publish response the SDK timed out and never republished, leaving the node Good on
the pre-change value indefinitely. New trailing reconcile read (Timeout +
KeepAliveInterval after recovery) publishes any Good value newer than the last
accepted one, through the replay guard's mark.
- IDriverConnectionLossSource (Core.Abstractions): opt-in definitive-loss signal.
DriverInstanceActor attaches in PreStart / detaches in PostStop and turns a raise
into a disconnect only while Connected. OpcUaClient raises once per session on
keep-alive BadSessionIdInvalid/BadSessionClosed/BadSessionNotActivated/
BadServerHalted (measured: the SDK never re-opens a halted channel) or a dropped
subscription; ambiguous codes stay with the #527 watchdog.
- Replay guard: one Information summary per recovery when the window closes
("dropped N late notifications across M refs"), with a timer so quiet
subscriptions log it too.
- ReconnectPeriod deleted (options, AdminUI form, docs, tests); stored configs that
carry reconnectPeriod still parse in the factory, probe and browser.
- Docs: OpcUaClient.md, DriverLifecycle.md, driver-specs.md, CLAUDE.md.
- BucketPlan: reverse processed reads anchored at the later time for every
aggregate: window (end, start], partial interval earliest, results stamped
with the later edge, latest first (SDK CreateSlice/GetTimestamp/backward
GetValues). SqlServer adds @bucketAdjustTicks + flips the window predicate;
QuestDB binds BucketBaseUnixTicks. IndexOf is the C# statement of the math.
- Partial bit on the interval the tag's data starts inside (SDK m_startOfData),
every aggregate but Average; per-sample reads fetch the earliest sample.
- Node manager: non-default client AggregateConfiguration =>
BadAggregateConfigurationRejected per node (ServerAggregateConfiguration,
pinned to the SDK AggregateManager defaults).
- GatewayTagProvisioner sends IntegralDivisor = 1.
- SDK parity oracle (Opc.Ua.Server calculators) in unit + both backends'
conformance suites, forward and reverse; remaining divergences documented.
- docs/Historian.md + CLAUDE.md release note (client-visible).
- IHistorianDataSource.ReadEventsAsync(..., bool reverse, ...) overload: reverse = Part 11 window (lo, hi]
newest-first by (time, id) DESC. Default forwards forward reads and throws NotSupportedException for
reverse (Null); Gateway refuses explicitly (ascending-only stream). Server answers
BadHistoryOperationUnsupported instead of silently returning the earliest N ascending.
- SqlServer / QuestDB serve reverse natively (ORDER BY time DESC, id DESC + TOP/LIMIT).
- Node manager: reverse event reads page with continuation points; direction stored in the cursor
(HistoryContinuationState.Reverse) so a resume continues in the cursor's direction; reverse tie clusters
over-fetched forward and sliced from the newest end (SliceTieCluster(reverse:)); end-only reads with a
cap page backward from EndTime (mirrors raw).
- Resumed event pages over-fetch by the boundary skip, so every non-final page is a full cap page.
- Tests: node-manager reverse paging (ties, clusters, coarse resolution, overfetch bound, resume
direction both ways, end-only, unsupported backend); shared EventReadConformance on SqlServer +
QuestDB; over-the-wire reverse paging; offline Gateway pin of the UTC DateTime.MaxValue bound through
the published client's proto conversion (in-process gRPC capture) and FILETIME.
- docs/Historian.md event paging section.
- HistoryUpdate items with SourceTimestamp > now + ServerHistorian:HistoryUpdateMaxFutureSkew
(default 1 day, <=0 disables) => BadOutOfRange in the node manager (every backend, never sent);
clock injected via OtOpcUaNodeManager.Clock (host TimeProvider).
- HistoryUpdate is Primary-only: off-Primary => BadInvalidState per node, after authorization,
same IDriverPrimaryRoleSource verdict as the native-ack gate; HistoryRead ungated.
- SqlServer: base schema requirement back to v1; SupportsModifiedTrail (v>=2). On v1 with
AutoCreateSchema=false: writes/reads/events/retention work, modified reads + HistoryUpdate =>
BadHistoryOperationUnsupported with nothing sent, retention skips SampleModified, one Warning per boot.
- QuestDB integration test pinning wall-clock TTL (far-future row evicts only partitions older
than the TTL by the wall clock), with a positive control.
- Docs: Historian.md, Configuration.md, security.md, CLAUDE.md (incl. QuestDB retry duplicates,
#674.4 anonymous-readable trail with ACL off, #674.5 not implemented).
Co-Authored-By: Claude <noreply@anthropic.com>
- EndpointSelector rewrites host AND port to the user-supplied URL (same scheme only)
- AggregateType/mapper/CLI/UI gain TimeAverage, TimeAverage2, Total, Total2, Interpolative
- HistoryReadCommand turns ServiceResultException into a one-line CommandException
- NodeManagerHistoryReadTests non-historized case sets IsReadModified=false
The F2 live gate failed (10 value regressions over 4 blips): IsLateReplay
disarmed a ref on its first in-order notification, which arrives ~1 s after
recovery, while the SDK's late replay lands 4-6 s later. Equal source times
also passed, so a replay equal to the recovery read got through.
While the window is open each ref now carries a high-water mark (seeded at
arming, raised by the recovery read, advanced by every accepted notification);
a notification at or below it is dropped (equal included — OPC UA moves the
source timestamp on every value/status change). Null source time passes
without moving the mark. Window expiry still disarms entirely, so an upstream
clock step-back is never frozen outside the window. Arm/expiry serialised by a
lock so an expiry racing a re-arm cannot wipe fresh seeds.
- HistoryModifiedValue gains explicit SourceTimeUtc (SqlServer + QuestDB populate it); the node manager's resume cursor uses it instead of the prior value's nullable source timestamp (MinValue for inserts).
- ACL test now uses a trail-returning data source and asserts Good + data on the allow leg.
- Node-manager tests: end-only backward open-ended paging, reverse resume cursor, null-prior cursor.
- QuestDB updater logs a Warning (tag + time range) when a sample write fails after its trail rows landed.
- docs/Historian.md: rolling-upgrade window, IDENTITY-vs-commit ordering, QuestDB cross-node ModifiedId clock ordering.
Every HistoryUpdate a SQL backend applies now leaves a modification trail
(prior value, principal, Part 11 update type, modification time), and
HistoryReadRaw with IsReadModified=true serves it as HistoryModifiedData.
- Core: HistoryUpdateContext threaded into all three IHistorianDataUpdater
methods; IHistorianDataSource.ReadModifiedAsync (default NotSupported =>
BadHistoryOperationUnsupported on Gateway/Null); HistoryModified* contracts.
- SqlServer: schema v2 (002_sample_modified.sql, RequiredVersion=2, docs copy);
trail written by OUTPUT ... INTO on the same MERGE/DELETE statement, so a
failed update leaves no audit row; retention purges SampleModified per tag on
the source-time cutoff; ReadModifiedAsync keyed on (SourceTimeUtc, ModifiedId).
- QuestDB: append-only {prefix}sample_modified (TTL like samples), trail row
written BEFORE the change (orphan-on-crash, never an untracked change);
existence reads now carry the prior value; ReadModifiedAsync.
- Node manager: modified reads dispatch + page via the #669 continuation store
(HistoryContinuationState gains HistoryCursorKind + LastModifiedId), gated by
the existing HistoryRead decision; session principal / key id passed to the
updater. IsDeleteModified stays unsupported.
- Client.CLI: historyread --modified.
- Tests: node-manager dispatch/paging/cursor binding/principal threading,
over-the-wire HistoryModifiedData, shared ModifiedValueConformance on both
backends, SqlServer atomicity (forced trail failure => no change) + v1->v2
upgrade + retention trail purge.
- Docs: Historian.md (Modified-value history section, schema v2 upgrade note),
security.md, Client.CLI.md, CLAUDE.md.
The global 'never older than the last Good source time' rule froze a node
whenever an upstream clock stepped backwards (NTP correction, PLC clock
reset) until the clock caught up. The check is now a replay guard armed
only by a same-session recovery (keep-alive bad->good): per ref it holds
the last Good upstream source time (raised by the recovery read), a ref
disarms on its first in-order notification, and the whole guard expires
after max(30 s, 2x the longest subscription keep-alive window). Outside
it every notification is accepted. The steady-state tracker records the
LAST accepted time, not a high-water mark.
F1: the driver's outage BadNoCommunication carried the last Good sample's
source timestamp. The recorder historizes SourceTimestampUtc ??
ServerTimestampUtc, so the Bad landed on the Good row's (TagId,
SourceTimeUtc) key and the insert-if-absent historian dropped it - no
outage marker until the host's watchdog marker ~95 s in, none at all for
a short blip. Now stamped with the detection time (source + server), as
the host's comms-loss fan does.
F2: after a same-session recovery the SDK delivered a missed notification
seconds late with an older source time and the node regressed. A
notification older than the newest Good upstream source time for its ref
(notification or recovery read) is dropped and counted
(stale_notification_dropped); equal timestamps pass; the outage Bad never
moves the comparison; a re-initialise resets it.
M1: the time-weighted family (incl. Total, formerly a pushed-down SUM) streams
raw window rows into the C# evaluator. New shared knob
ServerHistorian:MaxTimeWeightedRawRows (default 1,000,000; <=0 unbounded with a
Validate warning) flows through HistorianBackendRegistry into both providers.
The window query is capped at cap+1 (SQL Server TOP (@maxRows), QuestDB LIMIT $4);
one row past the cap throws the new Core.Abstractions
HistoryReadLimitExceededException, which the node manager maps to
BadTooManyOperations for that node. Not counted as a backend health failure;
bound rows are not counted; per-sample aggregates are not capped.
M2: reverse Interpolative is anchored at the later time (Part 13): points at
End - i*interval, emitted latest first. 10:00->09:00 @1h yields 10:00.
L1: Partial bit (0x4, = Opc.Ua.AggregateBits.Partial) on non-Bad results of a
truncated last interval (time-weighted family; per-sample family is a follow-up).
L2/L3: aligned with the SDK AggregateCalculator.GetTimeBasedStatusCode
(decompiled from Opc.Ua.Server 1.5.378.106): TreatUncertainAsBad=false counts
Uncertain time (Uncertain samples, held-into-outage, extrapolation) as Good
time; data but no non-Bad time => generic Bad (0x80000000); BadNoData only
when there is no data at all. Consequence: a live tag's latest interval reads
Good (documented).
L5: release note no longer claims Total matches the Gateway Integral exactly
(AVEVA's divisor is unverified); it notes Total is now evaluated in C# and
subject to the cap.
Tests: unit (reverse Interpolative x3, Partial, Bad vs BadNoData incl. an
open-ended outage, cap helpers, SDK bit oracles); conformance (reverse
Interpolative, raw-row cap at/over/0, bounds not counted, health unaffected);
node manager BadTooManyOperations; options default + warning. Each new
behaviour falsified by mutation (aggregator x9, data-source cap checks on
both backends against the real DBs, node-manager catch).
New AggregateFamily.TimeWeighted serving TimeAverage, TimeAverage2, Total,
Total2 and Interpolative, evaluated by the shared Sql.Common
TimeWeightedAggregator for both SQL backends (identical results by
construction). HistoryAggregateType gains TimeAverage2 + Total2 (appended);
OtOpcUaNodeManager.MapAggregate maps their NodeIds. Gateway's mapper already
refuses unknown defined members => BadAggregateNotSupported per node.
Semantics (server defaults, client AggregateConfiguration ignored):
TreatUncertainAsBad=false, PercentDataBad=PercentDataGood=100,
UseSlopedExtrapolation=false. Sloped for Double/Int64, stepped for Boolean;
a usable sample followed by a Bad one is held up to the outage (AtTime rule);
stepped Uncertain extrapolation past the last sample. TimeAverage/Total use
interpolated bounding (bridge outages); TimeAverage2/Total2 exclude Bad time.
Bounding values: latest usable + latest any before start, first any + first
usable at/after end (four TOP 1 / LIMIT 1 seeks).
CLIENT-VISIBLE: Total on SqlServer/QuestDb was SUM of samples; it is now the
time-weighted integral (TimeAverage x interval seconds), matching Gateway's
Integral. Release note in docs/Historian.md.
Trade-off (deviation from the preferred hybrid pushdown, allowed by the
design): the time-weighted family is NOT pushed down. Each read streams the
window's rows plus the four bounds (SQL Server: one five-result-set batch;
QuestDB: bounds UNION ALL + window select) into the C# evaluator. Network is
O(samples in window), memory O(buckets). Writing the per-segment
interpolation/edge splitting twice in two SQL dialects and keeping them
bit-identical was judged the bigger risk; this also makes the QuestDB
lag/lead spike moot.
Tests: 35 hand-computed TimeWeightedAggregator unit cases (each of 10
implementation mutations goes red); served-aggregate pin 13 -> 17;
conformance sparse fixture (intervals wider and narrower than sample gaps)
+ an outage straddling both window edges (each of the four SQL seeks
disabled in turn goes red); node-manager NodeId mapping test.
Joseph Doherty