Merge feat/668-modified-values: Part 11 modified-value history (IsReadModified) on SqlServer + QuestDB (#668)

2026-10-11 09:32:13 -04:00
parent 699871040a cfd403710e
commit 062086f9a6
51 changed files with 2173 additions and 195 deletions
@@ -135,6 +135,97 @@ public sealed class SqlServerHistorianDataSource : IHistorianDataSource
        }
    }

+    // ------------------------------------------------------------------------------------------ Modified (Part 11, #668)
+
+    /// <inheritdoc />
+    /// <remarks>
+    ///     Reads <c>SampleModified</c> (schema v2), the trail <see cref="SqlServerHistorianDataUpdater"/> writes in the
+    ///     same statement as each change. Windows follow <see cref="ReadRawAsync"/>; rows are ordered by
+    ///     <c>(SourceTimeUtc, ModifiedId)</c> (the clustered key after <c>TagId</c>, so a seek). <c>maxValues + 1</c> rows
+    ///     are fetched to report <see cref="HistoryModifiedReadResult.HasMore"/> exactly. An insert's audit row carries no
+    ///     prior value and is served <c>null</c> / <c>BadNoData</c>; its server timestamp is the modification time. An
+    ///     unknown tag is an empty result.
+    /// </remarks>
+    public async Task<HistoryModifiedReadResult> ReadModifiedAsync(
+        string fullReference, DateTime startUtc, DateTime endUtc, uint maxValues, HistoryModifiedCursor? resumeAfter,
+        CancellationToken cancellationToken)
+    {
+        ArgumentNullException.ThrowIfNull(fullReference);
+        var bounded = maxValues > 0 && maxValues < int.MaxValue;
+        try
+        {
+            var values = new List<HistoryModifiedValue>();
+            var hasMore = false;
+            var tagId = await ResolveAsync(fullReference, cancellationToken).ConfigureAwait(false);
+            if (tagId is { } id)
+            {
+                var reverse = startUtc > endUtc;
+                string where;
+                if (startUtc == endUtc) where = "SourceTimeUtc = @lo";
+                else if (!reverse) where = "SourceTimeUtc >= @lo AND SourceTimeUtc < @hi";
+                else where = "SourceTimeUtc > @lo AND SourceTimeUtc <= @hi";
+                if (resumeAfter is not null)
+                    where += reverse
+                        ? " AND (SourceTimeUtc < @ct OR (SourceTimeUtc = @ct AND ModifiedId < @cid))"
+                        : " AND (SourceTimeUtc > @ct OR (SourceTimeUtc = @ct AND ModifiedId > @cid))";
+                var order = reverse ? "DESC" : "ASC";
+                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 {(bounded ? "TOP (@take) " : "")}SourceTimeUtc, ValueKind, NumValue, IntValue, StrValue, StatusCode, " +
+                    "ServerTimeUtc, ModifiedId, ModificationTimeUtc, UpdateType, Principal " +
+                    $"FROM {_conn.Q("SampleModified")} WHERE TagId = @id AND {where} " +
+                    $"ORDER BY SourceTimeUtc {order}, ModifiedId {order}");
+                if (bounded) cmd.Parameters.Add(new SqlParameter("@take", SqlDbType.BigInt) { Value = (long)maxValues + 1 });
+                cmd.Parameters.Add(new SqlParameter("@id", SqlDbType.Int) { Value = id });
+                SqlHistorianConnection.AddDateTime2(cmd, "@lo", lo);
+                SqlHistorianConnection.AddDateTime2(cmd, "@hi", hi);
+                if (resumeAfter is not null)
+                {
+                    SqlHistorianConnection.AddDateTime2(cmd, "@ct", resumeAfter.SourceTimeUtc);
+                    cmd.Parameters.Add(new SqlParameter("@cid", SqlDbType.BigInt) { Value = resumeAfter.ModifiedId });
+                }
+
+                await using var reader = await cmd.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
+                while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
+                {
+                    if (bounded && values.Count == maxValues)
+                    {
+                        hasMore = true;
+                        break;
+                    }
+
+                    var sourceTime = SqlHistorianConnection.GetUtc(reader, 0);
+                    var modifiedAt = SqlHistorianConnection.GetUtc(reader, 8);
+                    DataValueSnapshot prior;
+                    if (reader.IsDBNull(1))
+                    {
+                        // An insert: there was no prior value.
+                        prior = new DataValueSnapshot(null, HistorianStatusCodes.BadNoData, sourceTime, modifiedAt);
+                    }
+                    else
+                    {
+                        var s = ReadStored(reader, 0);
+                        prior = new DataValueSnapshot(s.Value.ToObject(), s.Status, s.TimeUtc,
+                            reader.IsDBNull(6) ? modifiedAt : SqlHistorianConnection.GetUtc(reader, 6));
+                    }
+
+                    values.Add(new HistoryModifiedValue(
+                        prior, modifiedAt, (HistoryModificationType)reader.GetByte(9), reader.GetString(10), reader.GetInt64(7)));
+                }
+            }
+
+            RecordSuccess();
+            return new HistoryModifiedReadResult(values, hasMore);
+        }
+        catch (Exception ex)
+        {
+            RecordFailure(ex);
+            throw;
+        }
+    }
+
    // ------------------------------------------------------------------------------------------ AtTime

    /// <inheritdoc />