Files
lmxopcua/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.SqlServer/SqlServerHistorianDataSource.cs
T
Joseph Doherty 1f88669304 feat(historian): Part 13 time-weighted aggregates on SqlServer + QuestDb (#671)
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.
2026-10-11 08:44:44 -04:00

464 lines
26 KiB
C#
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
using System.Data;
using System.Text;
using Microsoft.Data.SqlClient;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Driver.Historian.Sql.Common;
namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.SqlServer;
/// <summary>
/// SQL Server read side of the historian (spec §4 "Reads"): Raw (forward / reverse / point), AtTime
/// (one statement, <c>TimeRow</c> TVP + two <c>OUTER APPLY</c>s), Events, and Processed aggregates pushed
/// down to T-SQL (<see cref="SqlAggregateQueries"/>).
/// </summary>
/// <remarks>
/// <para>
/// <b>Reads never create tags.</b> Tag names resolve through the shared <see cref="SqlServerTagCatalog"/>'s
/// read-only lookup (positive results cached); an unknown tag is a successful empty read (Raw), an
/// all-<c>BadNoData</c> read (AtTime / Processed), never an error.
/// </para>
/// <para>
/// <b>Faults.</b> A SQL / bootstrap exception is recorded in <see cref="GetHealthSnapshot"/> (so a missing
/// schema with <c>AutoCreateSchema=false</c> surfaces in <c>LastError</c>) and rethrown; the node manager
/// turns it into a per-node Bad. Client-request errors — an unsupported aggregate
/// (<see cref="HistoryAggregateNotSupportedException"/> ⇒ <c>BadAggregateNotSupported</c>) and a processed
/// window over <see cref="MaxProcessedBuckets"/> intervals (<see cref="ArgumentOutOfRangeException"/>, which
/// the node manager's generic catch surfaces as <c>BadHistoryOperationUnsupported</c> for that node only)
/// — are thrown before any I/O and are not counted as backend failures.
/// </para>
/// <para>
/// <b>Bad samples.</b> A stored sample is <i>usable</i> when its status severity is Good or Uncertain and it
/// carries a value; an <c>Empty</c>-kind sample is an outage marker (comms-loss <c>BadNoCommunication</c>
/// or a driver's Bad publish) and is Bad whatever its code. Raw returns every sample as stored, outage
/// markers included. Aggregates exclude Bad samples from the math, report the interval Uncertain when
/// any non-Good sample is present, and count them in PercentBad. AtTime never interpolates across a Bad
/// neighbour and reports a time inside an outage with the outage's Bad code (see <see cref="ReadAtTimeAsync"/>).
/// <b>An Empty sample is always served Bad:</b> a row with no value whose stored status is not Bad (only
/// possible for rows written before the writer forced Empty samples Bad) is read back as <c>BadNoData</c>,
/// on Raw and AtTime alike.
/// </para>
/// <para>
/// <b>Long names.</b> A tag name or event source name longer than <see cref="HistorianTagNames.MaxLength"/>
/// can never be stored, so it is answered as not found (Raw: empty; AtTime / Processed: <c>BadNoData</c>;
/// Events: none) without being truncated onto another series.
/// </para>
/// </remarks>
public sealed class SqlServerHistorianDataSource : IHistorianDataSource
{
/// <summary>Spec §9.7: a processed read covering more intervals than this is refused.</summary>
public const int MaxProcessedBuckets = BucketPlan.MaxBuckets;
private const string SampleColumns = "SourceTimeUtc, ValueKind, NumValue, IntValue, StrValue, StatusCode, ServerTimeUtc";
private readonly SqlHistorianConnection _conn;
private readonly SqlServerSchemaBootstrapper _bootstrap;
private readonly SqlServerTagCatalog _catalog;
private readonly ILogger _log;
private readonly TimeProvider _time;
private readonly HistorianHealthCounters _health = new();
/// <summary>Creates the data source over the provider's shared connection, bootstrapper and tag catalog.</summary>
/// <param name="conn">Connection helper.</param>
/// <param name="bootstrap">Schema bootstrapper (shared with the other SQL seams).</param>
/// <param name="catalog">Tag catalog (shared; reads use only its read-only lookup).</param>
/// <param name="log">Optional logger.</param>
/// <param name="timeProvider">Clock for "now" (AtTime beyond the last sample, server timestamps); system by default.</param>
internal SqlServerHistorianDataSource(
SqlHistorianConnection conn, SqlServerSchemaBootstrapper bootstrap, SqlServerTagCatalog catalog, ILogger? log = null,
TimeProvider? timeProvider = null)
{
_conn = conn ?? throw new ArgumentNullException(nameof(conn));
_bootstrap = bootstrap ?? throw new ArgumentNullException(nameof(bootstrap));
_catalog = catalog ?? throw new ArgumentNullException(nameof(catalog));
_log = log ?? NullLogger.Instance;
_time = timeProvider ?? TimeProvider.System;
}
// ------------------------------------------------------------------------------------------ Raw
/// <inheritdoc />
/// <remarks>
/// Forward (<c>start &lt; end</c>): <c>[start, end)</c> ascending. Reverse (<c>end &lt; start</c>, Part 11):
/// <c>(end, start]</c> descending. <c>start == end</c>: the sample exactly at that time (Part 11's point
/// read; it is also what the node manager's tie-cluster over-fetch asks for). <paramref name="maxValuesPerNode"/>
/// <c>0</c> is the node manager's "unbounded" sentinel; values above <see cref="int.MaxValue"/> clamp.
/// The node manager pages by re-reading from the last returned timestamp inclusive and trimming it; the
/// <c>(TagId, SourceTimeUtc)</c> primary key rules out tie clusters, so that is exact.
/// </remarks>
public async Task<HistoryReadResult> ReadRawAsync(
string fullReference, DateTime startUtc, DateTime endUtc, uint maxValuesPerNode, CancellationToken cancellationToken)
{
ArgumentNullException.ThrowIfNull(fullReference);
var top = maxValuesPerNode == 0 ? int.MaxValue : (int)Math.Min(maxValuesPerNode, int.MaxValue);
try
{
var tagId = await ResolveAsync(fullReference, cancellationToken).ConfigureAwait(false);
var samples = new List<DataValueSnapshot>();
if (tagId is { } id)
{
string where, order;
if (startUtc == endUtc) { where = "SourceTimeUtc = @lo"; order = "ASC"; }
else if (startUtc < endUtc) { where = "SourceTimeUtc >= @lo AND SourceTimeUtc < @hi"; order = "ASC"; }
else { where = "SourceTimeUtc > @lo AND SourceTimeUtc <= @hi"; order = "DESC"; }
var (lo, hi) = startUtc <= endUtc ? (startUtc, endUtc) : (endUtc, startUtc);
await using var conn = await _conn.OpenAsync(cancellationToken).ConfigureAwait(false);
await using var cmd = _conn.CreateCommand(conn,
$"SELECT TOP (@top) {SampleColumns} FROM {_conn.Q("Sample")} " +
$"WHERE TagId = @id AND {where} ORDER BY SourceTimeUtc {order}");
cmd.Parameters.Add(new SqlParameter("@top", SqlDbType.Int) { Value = top });
cmd.Parameters.Add(new SqlParameter("@id", SqlDbType.Int) { Value = id });
SqlHistorianConnection.AddDateTime2(cmd, "@lo", lo);
SqlHistorianConnection.AddDateTime2(cmd, "@hi", hi);
await using var reader = await cmd.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
{
var s = ReadStored(reader, 0);
samples.Add(new DataValueSnapshot(s.Value.ToObject(), s.Status, s.TimeUtc,
SqlHistorianConnection.GetUtc(reader, 6)));
}
}
RecordSuccess();
return new HistoryReadResult(samples, ContinuationPoint: null);
}
catch (Exception ex)
{
RecordFailure(ex);
throw;
}
}
// ------------------------------------------------------------------------------------------ AtTime
/// <inheritdoc />
/// <remarks>
/// One statement: the distinct requested times go in a <c>TimeRow</c> TVP and each picks up its
/// previous-or-equal (<c>p</c>) and next (<c>n</c>) stored sample via two <c>OUTER APPLY (SELECT TOP 1 …)</c>.
/// Rules, per requested time <c>T</c> (the result is stamped <c>T</c>):
/// <list type="bullet">
/// <item><c>p</c> at exactly <c>T</c> ⇒ the stored value and status, unchanged.</item>
/// <item>No <c>p</c> ⇒ <c>BadNoData</c>, null value.</item>
/// <item><c>p</c> Bad (incl. an <c>Empty</c> outage marker) ⇒ <c>T</c> lies inside an outage: null value
/// carrying <c>p</c>'s Bad status code (info bits stripped) — never better than its source, per the
/// quality contract (spec §4 as amended after the T10 review).</item>
/// <item><c>p</c> usable and <c>n</c> Bad ⇒ <c>p</c>'s value held (stepped, NOT interpolated into the outage)
/// with <c>UncertainDataSubNormal</c> + Interpolated bits.</item>
/// <item>Double/Int64 with a usable <c>n</c> ⇒ linear interpolation of <c>NumValue</c> (Int64 rounded to the
/// nearest integer, ties away from zero, keeping the type); status <c>Good</c> + Interpolated when both
/// neighbours are Good, else <c>UncertainDataSubNormal</c> + Interpolated (never better than the
/// inputs).</item>
/// <item>Boolean/String/DateTime, or no <c>n</c> (after the last sample) ⇒ stepped: <c>p</c>'s value with
/// <c>p</c>'s status code + Interpolated bits — except that a time later than now that is stepped from the
/// last sample is <c>UncertainDataSubNormal</c> + Interpolated (the value is not known to still hold).</item>
/// </list>
/// Unknown tag ⇒ every entry <c>BadNoData</c>.
/// </remarks>
public async Task<HistoryReadResult> ReadAtTimeAsync(
string fullReference, IReadOnlyList<DateTime> timestampsUtc, CancellationToken cancellationToken)
{
ArgumentNullException.ThrowIfNull(fullReference);
ArgumentNullException.ThrowIfNull(timestampsUtc);
try
{
var now = _time.GetUtcNow().UtcDateTime;
var byTicks = new Dictionary<long, DataValueSnapshot>(timestampsUtc.Count);
var tagId = timestampsUtc.Count == 0 ? null : await ResolveAsync(fullReference, cancellationToken).ConfigureAwait(false);
if (tagId is { } id)
{
var distinct = timestampsUtc.Select(t => DateTime.SpecifyKind(t, DateTimeKind.Utc)).Distinct().ToList();
var cols = "s.SourceTimeUtc, s.ValueKind, s.NumValue, s.IntValue, s.StrValue, s.StatusCode, s.ServerTimeUtc";
var sql =
$"SELECT r.T, p.*, n.* FROM @times r " +
$"OUTER APPLY (SELECT TOP 1 {cols} FROM {_conn.Q("Sample")} s WHERE s.TagId = @id AND s.SourceTimeUtc <= r.T ORDER BY s.SourceTimeUtc DESC) p " +
$"OUTER APPLY (SELECT TOP 1 {cols} FROM {_conn.Q("Sample")} s WHERE s.TagId = @id AND s.SourceTimeUtc > r.T ORDER BY s.SourceTimeUtc ASC) n";
await using var conn = await _conn.OpenAsync(cancellationToken).ConfigureAwait(false);
await using var cmd = _conn.CreateCommand(conn, sql);
cmd.Parameters.Add(new SqlParameter("@id", SqlDbType.Int) { Value = id });
_conn.AddStructured(cmd, "@times", "TimeRow", SampleRowMapper.ToTimeRecords(distinct));
await using var reader = await cmd.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
{
var t = SqlHistorianConnection.GetUtc(reader, 0);
StoredSample? p = reader.IsDBNull(1) ? null : ReadStored(reader, 1);
StoredSample? n = reader.IsDBNull(8) ? null : ReadStored(reader, 8);
var serverTime = p is { } ps && ps.TimeUtc == t ? SqlHistorianConnection.GetUtc(reader, 7) : now;
byTicks[t.Ticks] = AtTimeEvaluator.Evaluate(t, p, n, serverTime, now);
}
}
var result = new DataValueSnapshot[timestampsUtc.Count];
for (var i = 0; i < result.Length; i++)
{
var t = DateTime.SpecifyKind(timestampsUtc[i], DateTimeKind.Utc);
result[i] = byTicks.TryGetValue(t.Ticks, out var v)
? v
: new DataValueSnapshot(null, HistorianStatusCodes.BadNoData, t, now);
}
RecordSuccess();
return new HistoryReadResult(result, ContinuationPoint: null);
}
catch (Exception ex)
{
RecordFailure(ex);
throw;
}
}
// ------------------------------------------------------------------------------------------ Events
/// <inheritdoc />
/// <remarks>
/// <c>[start, end)</c> by <c>EventTimeUtc</c> (a reversed window is swapped), ordered by
/// <c>(EventTimeUtc, EventId)</c> ascending — the clustered index. <paramref name="maxEvents"/> &lt;= 0 or
/// <see cref="int.MaxValue"/> (the node manager's "no limit") ⇒ unbounded. Otherwise <c>maxEvents + 1</c>
/// rows are fetched; when the extra row arrives it is dropped and the continuation point is the UTF-8
/// of <c>"{EventTimeUtc.Ticks}|{EventId}"</c> of that first not-returned event (opaque to callers; only
/// its presence is contractual).
/// </remarks>
public async Task<HistoricalEventsResult> ReadEventsAsync(
string? sourceName, DateTime startUtc, DateTime endUtc, int maxEvents, CancellationToken cancellationToken)
{
// No stored event can carry a source longer than the column (the alarm writer dead-letters it rather than
// truncating), so an over-long filter matches nothing — never a truncated prefix of someone else's source.
if (sourceName is not null && sourceName.Length > HistorianTagNames.MaxLength)
return new HistoricalEventsResult([], null);
try
{
await _bootstrap.EnsureAsync(cancellationToken).ConfigureAwait(false);
var (lo, hi) = startUtc <= endUtc ? (startUtc, endUtc) : (endUtc, startUtc);
var bounded = maxEvents > 0 && maxEvents < int.MaxValue;
var sql =
$"SELECT {(bounded ? "TOP (@take) " : "")}EventId, SourceName, EventTimeUtc, ReceivedTimeUtc, Message, Severity " +
$"FROM {_conn.Q("Event")} WHERE EventTimeUtc >= @lo AND EventTimeUtc < @hi" +
(sourceName is null ? "" : " AND SourceName = @source") +
" ORDER BY EventTimeUtc ASC, EventId ASC";
await using var conn = await _conn.OpenAsync(cancellationToken).ConfigureAwait(false);
await using var cmd = _conn.CreateCommand(conn, sql);
if (bounded) cmd.Parameters.Add(new SqlParameter("@take", SqlDbType.BigInt) { Value = (long)maxEvents + 1 });
SqlHistorianConnection.AddDateTime2(cmd, "@lo", lo);
SqlHistorianConnection.AddDateTime2(cmd, "@hi", hi);
if (sourceName is not null)
cmd.Parameters.Add(new SqlParameter("@source", SqlDbType.NVarChar, SqlServerTagCatalog.MaxNameLength) { Value = sourceName });
var events = new List<HistoricalEvent>();
byte[]? continuation = null;
await using var reader = await cmd.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
{
var e = new HistoricalEvent(
reader.GetString(0),
reader.GetString(1),
SqlHistorianConnection.GetUtc(reader, 2),
SqlHistorianConnection.GetUtc(reader, 3),
reader.IsDBNull(4) ? null : reader.GetString(4),
HistoricalEventRows.ClampSeverity(reader.GetInt32(5)));
if (bounded && events.Count == maxEvents)
{
continuation = Encoding.UTF8.GetBytes(EventContinuation.Encode(e.EventTimeUtc, e.EventId));
break;
}
events.Add(e);
}
RecordSuccess();
return new HistoricalEventsResult(events, continuation);
}
catch (Exception ex)
{
RecordFailure(ex);
throw;
}
}
// ------------------------------------------------------------------------------------------ Processed
/// <inheritdoc />
/// <remarks>
/// <para>
/// One result per interval of <c>[start, end)</c>, bucket <c>i</c> = <c>[start + i·interval,
/// start + (i+1)·interval)</c> (start-inclusive, end-exclusive to the tick; the last bucket is truncated at
/// <c>end</c>). <paramref name="interval"/> &lt;= 0 ⇒ one interval <c>[start, end)</c>. <c>start == end</c>
/// ⇒ no intervals. <c>end &lt; start</c> (reverse) ⇒ the window is swapped, computed forward, and returned
/// in descending bucket order (buckets stay anchored at the earlier time).
/// </para>
/// <para>
/// Per interval: no samples ⇒ <c>BadNoData</c>. PercentGood / PercentBad ⇒ <c>100 × good|bad / all</c> over
/// every sample, status Good. Otherwise no usable sample ⇒ <c>BadNoData</c>; a numeric aggregate with a usable
/// String/DateTime sample ⇒ <c>BadAggregateInvalidInputs</c>; else the value, Good when every sample is Good,
/// <c>UncertainDataSubNormal</c> when any is Bad or Uncertain. Every status — including <c>BadNoData</c> —
/// carries the Calculated info bits. Timestamps are the bucket start, except Minimum/MaximumActualTime
/// (the sample's time; ties ⇒ earliest).
/// </para>
/// <para>
/// Values: Count is <see cref="int"/>; Start/End keep the sample's type; every other aggregate is
/// <see cref="double"/> computed over <c>NumValue</c> (Boolean = 0/1). These are the simple per-sample
/// definitions. The Part 13 time-weighted family (TimeAverage, TimeAverage2, Total, Total2, Interpolative, #671) is
/// not pushed down: the window's rows plus four bounding rows are streamed into the shared
/// <see cref="TimeWeightedAggregator"/>, which fills every interval (an empty one between bounds gets a value).
/// </para>
/// </remarks>
/// <exception cref="HistoryAggregateNotSupportedException">The aggregate is not one of the seventeen served.</exception>
/// <exception cref="ArgumentOutOfRangeException">The window holds more than <see cref="MaxProcessedBuckets"/> intervals.</exception>
public async Task<HistoryReadResult> ReadProcessedAsync(
string fullReference, DateTime startUtc, DateTime endUtc, TimeSpan interval,
HistoryAggregateType aggregate, CancellationToken cancellationToken)
{
ArgumentNullException.ThrowIfNull(fullReference);
var family = AggregateFamilies.FamilyOf(aggregate) ?? throw new HistoryAggregateNotSupportedException(aggregate);
var plan = BucketPlan.Create(startUtc, endUtc, interval);
try
{
var now = _time.GetUtcNow().UtcDateTime;
var evaluated = new Dictionary<long, DataValueSnapshot>();
var tagId = plan.BucketCount == 0 ? null : await ResolveAsync(fullReference, cancellationToken).ConfigureAwait(false);
if (family == AggregateFamily.TimeWeighted)
{
var tw = new TimeWeightedAggregator(aggregate, plan);
if (tagId is { } twId) await StreamTimeWeightedAsync(twId, plan, tw, cancellationToken).ConfigureAwait(false);
var twResult = tw.Finish(now);
RecordSuccess();
return new HistoryReadResult(twResult, ContinuationPoint: null);
}
if (tagId is { } id)
{
var sample = _conn.Q("Sample");
var sql = family switch
{
AggregateFamily.Simple => SqlAggregateQueries.Simple(sample),
AggregateFamily.StartEnd => SqlAggregateQueries.StartEnd(sample),
_ => SqlAggregateQueries.ActualTime(sample, aggregate == HistoryAggregateType.MaximumActualTime),
};
await using var conn = await _conn.OpenAsync(cancellationToken).ConfigureAwait(false);
await using var cmd = _conn.CreateCommand(conn, sql);
cmd.Parameters.Add(new SqlParameter("@id", SqlDbType.Int) { Value = id });
SqlHistorianConnection.AddDateTime2(cmd, "@start", DateTime.SpecifyKind(plan.StartUtc, DateTimeKind.Utc));
SqlHistorianConnection.AddDateTime2(cmd, "@end", DateTime.SpecifyKind(plan.EndUtc, DateTimeKind.Utc));
cmd.Parameters.Add(new SqlParameter("@intervalTicks", SqlDbType.BigInt) { Value = plan.IntervalTicks });
await using var reader = await cmd.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
{
var row = ReadBucket(reader, family);
evaluated[row.Bucket] = AggregateEvaluator.Evaluate(aggregate, row, plan.BucketStart(row.Bucket), now);
}
}
var result = plan.Assemble(evaluated, bucketStart => AggregateEvaluator.NoData(bucketStart, now));
RecordSuccess();
return new HistoryReadResult(result, ContinuationPoint: null);
}
catch (Exception ex)
{
RecordFailure(ex);
throw;
}
}
/// <summary>
/// Streams the time-weighted batch (<see cref="SqlAggregateQueries.TimeWeighted"/>) into <paramref name="tw"/>: the
/// two before-bounds, the window, the two after-bounds — ascending, with duplicates dropped by the aggregator.
/// </summary>
private async Task StreamTimeWeightedAsync(int id, BucketPlan plan, TimeWeightedAggregator tw, CancellationToken ct)
{
await using var conn = await _conn.OpenAsync(ct).ConfigureAwait(false);
await using var cmd = _conn.CreateCommand(conn, SqlAggregateQueries.TimeWeighted(_conn.Q("Sample")));
cmd.Parameters.Add(new SqlParameter("@id", SqlDbType.Int) { Value = id });
SqlHistorianConnection.AddDateTime2(cmd, "@start", DateTime.SpecifyKind(plan.StartUtc, DateTimeKind.Utc));
SqlHistorianConnection.AddDateTime2(cmd, "@end", DateTime.SpecifyKind(plan.EndUtc, DateTimeKind.Utc));
await using var reader = await cmd.ExecuteReaderAsync(ct).ConfigureAwait(false);
do
{
while (await reader.ReadAsync(ct).ConfigureAwait(false))
tw.Add(ReadStored(reader, 0));
} while (await reader.NextResultAsync(ct).ConfigureAwait(false));
}
private static BucketRow ReadBucket(SqlDataReader reader, AggregateFamily family)
{
static double? D(SqlDataReader r, int i) => r.IsDBNull(i) ? null : r.GetDouble(i);
static long? L(SqlDataReader r, int i) => r.IsDBNull(i) ? null : r.GetInt64(i);
static string? S(SqlDataReader r, int i) => r.IsDBNull(i) ? null : r.GetString(i);
static HistorianValue V(SqlDataReader r, int i) =>
r.IsDBNull(i) ? HistorianValue.Empty : SampleColumnMapper.FromColumns(r.GetByte(i), D(r, i + 1), L(r, i + 2), S(r, i + 3));
var row = new BucketRow
{
Bucket = reader.GetInt64(0),
Total = reader.GetInt32(1),
Usable = reader.GetInt32(2),
Good = reader.GetInt32(3),
Bad = reader.GetInt32(4),
NonNumeric = reader.GetInt32(5),
};
var f = SqlAggregateQueries.FirstFamilyColumn;
switch (family)
{
case AggregateFamily.Simple:
row.Avg = D(reader, f);
row.Min = D(reader, f + 1);
row.Max = D(reader, f + 2);
row.Sum = D(reader, f + 3);
break;
case AggregateFamily.StartEnd:
row.First = V(reader, f);
row.Last = V(reader, f + 5);
break;
default:
row.Extreme = D(reader, f);
row.ExtremeTime = reader.IsDBNull(f + 1) ? null : SqlHistorianConnection.GetUtc(reader, f + 1);
break;
}
return row;
}
// ------------------------------------------------------------------------------------------ Shared
/// <summary>
/// Reads <c>SourceTimeUtc, ValueKind, NumValue, IntValue, StrValue, StatusCode</c> starting at <paramref name="o"/>.
/// An Empty (no-value) row whose stored status is not Bad is clamped to <c>BadNoData</c>
/// (<see cref="StoredSample.FromStored"/>) — defence in depth for rows written before the writer forced every
/// Empty sample Bad.
/// </summary>
private static StoredSample ReadStored(SqlDataReader r, int o)
{
var value = SampleColumnMapper.FromColumns(
r.GetByte(o + 1),
r.IsDBNull(o + 2) ? null : r.GetDouble(o + 2),
r.IsDBNull(o + 3) ? null : r.GetInt64(o + 3),
r.IsDBNull(o + 4) ? null : r.GetString(o + 4));
var status = SampleColumnMapper.FromDbStatus(r.GetInt32(o + 5));
return StoredSample.FromStored(SqlHistorianConnection.GetUtc(r, o), value, status);
}
/// <summary>Read-only tag lookup (never creates a row); runs the schema bootstrap on a cache miss.</summary>
private Task<int?> ResolveAsync(string name, CancellationToken ct) => _catalog.TryGetTagIdAsync(name, ct);
// ------------------------------------------------------------------------------------------ Health
/// <inheritdoc />
public HistorianHealthSnapshot GetHealthSnapshot() => _health.Snapshot();
private void RecordSuccess() => _health.RecordSuccess();
private void RecordFailure(Exception ex)
{
// A cancelled read (deadline / client abort) is not a backend fault (the counters ignore it too).
if (ex is OperationCanceledException) return;
_health.RecordFailure(ex);
_log.LogDebug("SQL historian read failed ({ExceptionType})", ex.GetType().Name);
}
/// <inheritdoc />
public void Dispose()
{
// Connections are per call (pooled by SqlClient); nothing to release.
}
}