perf(central): set-based ingest, aligned partition purge, KPI query shapes, EF hygiene

src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Repositories/KpiHistoryRepository.cs

@@ -128,6 +128,37 @@ public sealed class KpiHistoryRepository : IKpiHistoryRepository
         var groups = samples.GroupBy(s => new SeriesHourKey(
             s.Source, s.Metric, s.Scope, s.ScopeKey, TruncateToHour(s.CapturedAtUtc)));
 
+        // Preload every rollup row already covering this window in ONE query and
+        // index it by series+hour (WP2.2). The predecessor issued a
+        // FirstOrDefaultAsync existence probe PER (series, hour) group — an N+1
+        // that scaled with the metric catalogue times the lookback: a 3 h re-fold
+        // over ~40 series cost ~120 sequential round trips before a single row was
+        // written. The window is bounded by the caller's small trailing lookback
+        // and the rollup table holds exactly one row per series-hour, so the
+        // preload is a narrow range seek on IX_KpiRollupHourly_Series.
+        //
+        // Deliberately TRACKED (not a projection): the re-fold path mutates the
+        // existing entity in place and relies on the change tracker to emit the
+        // UPDATE. The dictionary's ScopeKey comparison is ordinal where the
+        // previous SQL predicate used the database collation; both sides are
+        // written from the same KpiSample.ScopeKey values, so they are
+        // byte-identical in practice and a residual mismatch degrades to the
+        // already-handled upsert-race path rather than a wrong aggregate.
+        var existingRollups = await _context.KpiRollupHourly
+            .Where(r => r.HourStartUtc >= from && r.HourStartUtc < to)
+            .ToListAsync(cancellationToken);
+
+        var existingByKey = new Dictionary<SeriesHourKey, KpiRollupHourly>(existingRollups.Count);
+        foreach (var row in existingRollups)
+        {
+            existingByKey[new SeriesHourKey(
+                row.Source,
+                row.Metric,
+                row.Scope,
+                row.ScopeKey,
+                DateTime.SpecifyKind(row.HourStartUtc, DateTimeKind.Utc))] = row;
+        }
+
         foreach (var group in groups)
         {
             var key = group.Key;
@@ -143,18 +174,11 @@ public sealed class KpiHistoryRepository : IKpiHistoryRepository
             var maxValue = group.Max(s => s.Value);
             var sampleCount = group.Count();
 
-            // Idempotent upsert on the unique series+hour key. The ScopeKey == key.ScopeKey
-            // comparison matches null against the Global-scope rows (IS NULL) exactly as the
-            // UNIQUE IX_KpiRollupHourly_Series index treats a null key as participating.
-            var existing = await _context.KpiRollupHourly.FirstOrDefaultAsync(
-                r => r.Source == key.Source
-                    && r.Metric == key.Metric
-                    && r.Scope == key.Scope
-                    && r.ScopeKey == key.ScopeKey
-                    && r.HourStartUtc == key.HourStartUtc,
-                cancellationToken);
-
-            if (existing is null)
+            // Idempotent upsert on the unique series+hour key, resolved against the
+            // preloaded dictionary. A null ScopeKey keys the Global-scope rows exactly
+            // as the UNIQUE IX_KpiRollupHourly_Series index treats a null key as
+            // participating.
+            if (!existingByKey.TryGetValue(key, out var existing))
             {
                 _context.KpiRollupHourly.Add(new KpiRollupHourly
                 {