perf(site-call-audit): filtered IX_SiteCalls_NonTerminal index — KPI predicates seek the live queue instead of scanning 365 days

src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Configurations/SiteCallEntityTypeConfiguration.cs

@@ -66,8 +66,9 @@ public class SiteCallEntityTypeConfiguration : IEntityTypeConfiguration<SiteCall
         // SourceNode (SourceNode-stamping): node-local identifier of the
         // cluster member that produced the call (e.g. "node-a", "central-a"). NULL is
         // valid for rows that pre-date this feature and for reconciled rows from a
-        // retired node. ASCII — varchar(64). No index — Site Call Audit KPIs are
-        // per-site, not per-node, on this table.
+        // retired node. ASCII — varchar(64). Not a key column of any index, but it rides
+        // as an INCLUDE column on IX_SiteCalls_NonTerminal below so the per-node KPI
+        // breakdown reads it covered off the filtered live-queue index.
         builder.Property(s => s.SourceNode)
             .HasColumnType("varchar(64)")
             .HasMaxLength(64)
@@ -85,5 +86,16 @@ public class SiteCallEntityTypeConfiguration : IEntityTypeConfiguration<SiteCall
         builder.HasIndex(s => new { s.Status, s.UpdatedAtUtc })
             .IsDescending(false, true)
             .HasDatabaseName("IX_SiteCalls_Status_Updated");
+
+        // NonTerminal backs every "live queue" KPI predicate (TerminalAtUtc IS NULL):
+        // buffered/stuck/oldest counts run every 60 s from the KPI recorder plus every
+        // 10 s Health-dashboard poll. Filtered: the non-terminal population is the live
+        // queue, not the 365-day archive — each count becomes a small seek instead of a
+        // clustered scan (arch-review 04, P1). SourceSite/SourceNode/Status ride as
+        // INCLUDE columns so the per-site + per-node KPI breakdowns stay covered.
+        builder.HasIndex(s => s.CreatedAtUtc)
+            .HasDatabaseName("IX_SiteCalls_NonTerminal")
+            .HasFilter("[TerminalAtUtc] IS NULL")
+            .IncludeProperties(nameof(SiteCall.SourceSite), nameof(SiteCall.SourceNode), nameof(SiteCall.Status));
     }
 }

src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Migrations/20260709110614_AddSiteCallsNonTerminalIndex.cs

@@ -0,0 +1,29 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddSiteCallsNonTerminalIndex : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateIndex(
+                name: "IX_SiteCalls_NonTerminal",
+                table: "SiteCalls",
+                column: "CreatedAtUtc",
+                filter: "[TerminalAtUtc] IS NULL")
+                .Annotation("SqlServer:Include", new[] { "SourceSite", "SourceNode", "Status" });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropIndex(
+                name: "IX_SiteCalls_NonTerminal",
+                table: "SiteCalls");
+        }
+    }
+}

src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Migrations/ScadaBridgeDbContextModelSnapshot.cs

@@ -161,6 +161,12 @@ namespace ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Migrations
 
                     b.HasKey("TrackedOperationId");
 
+                    b.HasIndex("CreatedAtUtc")
+                        .HasDatabaseName("IX_SiteCalls_NonTerminal")
+                        .HasFilter("[TerminalAtUtc] IS NULL");
+
+                    SqlServerIndexBuilderExtensions.IncludeProperties(b.HasIndex("CreatedAtUtc"), new[] { "SourceSite", "SourceNode", "Status" });
+
                     b.HasIndex("SourceSite", "CreatedAtUtc")
                         .IsDescending(false, true)
                         .HasDatabaseName("IX_SiteCalls_Source_Created");