Per-sample aggregates (all but Average) now set Partial on a reverse read's interval
that strictly contains the tag's latest sample — the SDK's reverse m_startOfData
(verified vs the SDK harness), matching lane A's time-weighted rule. NeedsDataRange
therefore applies in both directions for every per-sample aggregate but Average.
PercentGood/Bad left the per-sample evaluator (lane A moved them to the time-weighted
family); Evaluate refuses non-per-sample aggregates up front. Comments fixed.
Count: Good samples only, value-based status (all Bad => generic Bad), 0/Good on an
empty interval inside the tag's data range [first, last] (both directions).
Start/End: the raw first/last sample of any quality (own value, status, timestamp).
Delta: Uncertain only when the interval's first or last sample is not usable.
Forward end-of-data Partial (SDK m_endOfData, earlier edge inclusive) for every
per-sample aggregate but Average (PercentGood/Bad left to lane A).
Backends push down first/last-any-quality columns and fetch the tag's data range
(earliest <= window end, latest >= window start) only when NeedsDataRange.
SDK parity masks for Start/End/Delta/Count removed; new parity datasets.
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.
- 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).
51 new test cases (34 methods) in Sql.Common.Tests covering AtTimeEvaluator, AggregateEvaluator
(hand-built tag-A bucket rows, ProcessedRead literals), BucketPlan, LiveWritePreparer and
HistoryUpdatePlanner (incl. resolutionTicks=10 truncate-before-dedup and the superseded-duplicate
outcome), plus EventContinuation, HistorianHealthCounters, ClampSeverity and StoredSample.FromStored.
Each was falsified by reverting the rule it pins (37 mutations, all red, all restored).
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Joseph Doherty