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fix(historian): #691.3 strict-ceiling gateway: re-ask once at the named ceiling, never answer a truncated read

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This commit is contained in:
Joseph Doherty
2026-10-12 16:13:14 -04:00
parent 39552e15b9
commit dbffb6bdb4
7 changed files with 391 additions and 56 deletions
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src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway/RawAggregateReader.cs
+41 -26
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@@ -49,7 +49,10 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway;
/// requested row budget — has been drained. The gateway is asked for at most <c>cap + 2 + </c>
/// <see cref="PreWindowAllowance"/> rows, clamped at <see cref="GatewayDefaultMaxValuesCeiling"/> while the cap is at
/// or under it (#688, <see cref="ClampToGatewayCeiling"/>); a stream that delivers all of them cannot be proven
/// complete and fails the same way rather than answering from a truncated window.
/// complete and fails the same way rather than answering from a truncated window. A strict gateway whose ceiling is
/// below that budget (a ceiling under 1,000,000, or an unbounded cap) refuses it naming its ceiling; the window is
/// then re-read once with the ceiling as budget (#691.3, <see cref="GatewayReadLimits"/>), and the same
/// "delivered the whole budget ⇒ cannot be proven complete" rule applies.
/// </para>
/// <para>
/// <b>Values and status.</b> A sample's value is its numeric value (Double), else its string value, else Empty; its
@@ -178,8 +181,43 @@ internal static class RawAggregateReader
if (plan.BucketCount == 0) return [];
var needsRange = AggregateEvaluator.NeedsDataRange(aggregate, plan);
var requestStart = RequestStartFor(plan.StartUtc);
var maxValues = MaxValuesFor(maxWindowRows);
// A strict gateway that refuses the budget is re-asked once at the ceiling it names (#691.3; e.g. a ceiling below
// the 1,000,000 #688 clamps at, or an unbounded cap) — and a stream that fills that ceiling is never evaluated.
var (pass, maxValues) = await GatewayReadLimits.ReadWithCeilingRetryAsync(MaxValuesFor(maxWindowRows),
budget => ReadWindowAsync(client, tag, aggregate, plan, requestStart, budget, maxWindowRows, ct)).ConfigureAwait(false);
var (buckets, earliest, latest, received, overCap) = pass;
if (overCap || received >= maxValues)
throw LimitExceeded(tag, maxWindowRows);
if (needsRange)
{
// Earlier data: no non-Bad pre-window row ⇒ ask explicitly (normally only when the tag's history really starts
// inside the window).
var earlierSeen = earliest is { } e && (e < plan.StartUtc || (plan.Reversed && e == plan.StartUtc));
if (!earlierSeen && plan.StartUtc.AddTicks(-1) > ProbeFloor)
if (await FirstSampleAsync(client, tag, ProbeFloor, plan.StartUtc.AddTicks(-1), ct).ConfigureAwait(false) is { } before)
earliest = before;
// Later data: the main read covers a sample exactly at the window end (forward: that is already later data);
// otherwise a small separate read from the end to now + horizon.
var laterSeen = latest is { } l && (plan.Reversed ? l > plan.EndUtc : l >= plan.EndUtc);
var horizon = DateTime.MaxValue - now > LookAheadHorizon
? DateTime.SpecifyKind(now + LookAheadHorizon, DateTimeKind.Utc)
: DateTime.MaxValue;
if (!laterSeen && horizon > plan.EndUtc)
if (await FirstSampleAsync(client, tag, plan.EndUtc, horizon, ct).ConfigureAwait(false) is { } after)
latest = after;
}
return AggregateEvaluator.EvaluateAll(aggregate, plan, buckets.Rows(), earliest, latest, now);
}
/// <summary>The window read of <see cref="ReadAsync"/> with one row budget, drained.</summary>
private static async Task<(RawBucketAccumulator Buckets, DateTime? Earliest, DateTime? Latest, long Received, bool OverCap)>
ReadWindowAsync(IHistorianGatewayClient client, string tag, HistoryAggregateType aggregate, BucketPlan plan,
DateTime requestStart, int maxValues, int maxWindowRows, CancellationToken ct)
{
var buckets = new RawBucketAccumulator(aggregate == HistoryAggregateType.MaximumActualTime);
DateTime? earliest = null, latest = null;
long windowRows = 0, received = 0;
@@ -214,30 +252,7 @@ internal static class RawAggregateReader
if (t >= plan.StartUtc && (latest is null || t > latest)) latest = t;
}
}
if (overCap || (maxWindowRows > 0 && received >= maxValues))
throw LimitExceeded(tag, maxWindowRows);
if (needsRange)
{
// Earlier data: no non-Bad pre-window row ⇒ ask explicitly (normally only when the tag's history really starts
// inside the window).
var earlierSeen = earliest is { } e && (e < plan.StartUtc || (plan.Reversed && e == plan.StartUtc));
if (!earlierSeen && plan.StartUtc.AddTicks(-1) > ProbeFloor)
if (await FirstSampleAsync(client, tag, ProbeFloor, plan.StartUtc.AddTicks(-1), ct).ConfigureAwait(false) is { } before)
earliest = before;
// Later data: the main read covers a sample exactly at the window end (forward: that is already later data);
// otherwise a small separate read from the end to now + horizon.
var laterSeen = latest is { } l && (plan.Reversed ? l > plan.EndUtc : l >= plan.EndUtc);
var horizon = DateTime.MaxValue - now > LookAheadHorizon
? DateTime.SpecifyKind(now + LookAheadHorizon, DateTimeKind.Utc)
: DateTime.MaxValue;
if (!laterSeen && horizon > plan.EndUtc)
if (await FirstSampleAsync(client, tag, plan.EndUtc, horizon, ct).ConfigureAwait(false) is { } after)
latest = after;
}
return AggregateEvaluator.EvaluateAll(aggregate, plan, buckets.Rows(), earliest, latest, now);
return (buckets, earliest, latest, received, overCap);
}
/// <summary>