Improve index performance on Entity Framework persisters

src/ServiceControl.Persistence.EFCore.PostgreSql/Migrations/20260911041328_AddMissingIndexes.cs

@@ -0,0 +1,97 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ServiceControl.Persistence.EFCore.PostgreSql.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddMissingIndexes : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropIndex(
+                name: "ix_failed_messages_status_last_modified",
+                table: "failed_messages");
+
+            migrationBuilder.DropIndex(
+                name: "ix_failed_message_groups_type_group_id",
+                table: "failed_message_groups");
+
+            migrationBuilder.AlterColumn<string>(
+                name: "message_type",
+                table: "failed_messages",
+                type: "character varying(450)",
+                maxLength: 450,
+                nullable: true,
+                oldClrType: typeof(string),
+                oldType: "text",
+                oldNullable: true);
+
+            migrationBuilder.CreateIndex(
+                name: "ix_failed_messages_status_last_modified",
+                table: "failed_messages",
+                columns: new[] { "status", "last_modified" })
+                .Annotation("Npgsql:IndexInclude", new[] { "first_time_of_failure", "last_time_of_failure" });
+
+            migrationBuilder.CreateIndex(
+                name: "ix_failed_messages_status_last_time_of_failure",
+                table: "failed_messages",
+                columns: new[] { "status", "last_time_of_failure" });
+
+            // Normally this would be potentially slow and necessitate executing outside of the
+            // migration transaction, but no customers consume this persister yet so this can
+            // be treated as an initial migration
+            migrationBuilder.CreateIndex(
+                name: "ix_failed_messages_status_message_type_unique_message_id",
+                table: "failed_messages",
+                columns: new[] { "status", "message_type", "unique_message_id" });
+
+            migrationBuilder.CreateIndex(
+                name: "ix_failed_message_groups_type_group_id",
+                table: "failed_message_groups",
+                columns: new[] { "type", "group_id" })
+                .Annotation("Npgsql:IndexInclude", new[] { "title" });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropIndex(
+                name: "ix_failed_messages_status_last_modified",
+                table: "failed_messages");
+
+            migrationBuilder.DropIndex(
+                name: "ix_failed_messages_status_last_time_of_failure",
+                table: "failed_messages");
+
+            migrationBuilder.DropIndex(
+                name: "ix_failed_messages_status_message_type_unique_message_id",
+                table: "failed_messages");
+
+            migrationBuilder.DropIndex(
+                name: "ix_failed_message_groups_type_group_id",
+                table: "failed_message_groups");
+
+            migrationBuilder.AlterColumn<string>(
+                name: "message_type",
+                table: "failed_messages",
+                type: "text",
+                nullable: true,
+                oldClrType: typeof(string),
+                oldType: "character varying(450)",
+                oldMaxLength: 450,
+                oldNullable: true);
+
+            migrationBuilder.CreateIndex(
+                name: "ix_failed_messages_status_last_modified",
+                table: "failed_messages",
+                columns: new[] { "status", "last_modified" });
+
+            migrationBuilder.CreateIndex(
+                name: "ix_failed_message_groups_type_group_id",
+                table: "failed_message_groups",
+                columns: new[] { "type", "group_id" });
+        }
+    }
+}

src/ServiceControl.Persistence.EFCore.PostgreSql/Migrations/PostgreSqlServiceControlDbContextModelSnapshot.cs

@@ -371,7 +371,8 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .HasColumnName("message_id");
 
                     b.Property<string>("MessageType")
-                        .HasColumnType("text")
+                        .HasMaxLength(450)
+                        .HasColumnType("character varying(450)")
                         .HasColumnName("message_type");
 
                     b.Property<int>("NumberOfProcessingAttempts")
@@ -440,6 +441,14 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.HasIndex("Status", "LastModified")
                         .HasDatabaseName("ix_failed_messages_status_last_modified");
 
+                    NpgsqlIndexBuilderExtensions.IncludeProperties(b.HasIndex("Status", "LastModified"), new[] { "FirstTimeOfFailure", "LastTimeOfFailure" });
+
+                    b.HasIndex("Status", "LastTimeOfFailure")
+                        .HasDatabaseName("ix_failed_messages_status_last_time_of_failure");
+
+                    b.HasIndex("Status", "MessageType", "UniqueMessageId")
+                        .HasDatabaseName("ix_failed_messages_status_message_type_unique_message_id");
+
                     b.ToTable("failed_messages", (string)null);
                 });
 
@@ -474,6 +483,8 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.HasIndex("Type", "GroupId")
                         .HasDatabaseName("ix_failed_message_groups_type_group_id");
 
+                    NpgsqlIndexBuilderExtensions.IncludeProperties(b.HasIndex("Type", "GroupId"), new[] { "Title" });
+
                     b.ToTable("failed_message_groups", (string)null);
                 });
 

src/ServiceControl.Persistence.EFCore.PostgreSql/PostgreSqlServiceControlDbContext.cs

@@ -23,6 +23,18 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
         modelBuilder.Entity<FailedMessageEntity>()
             .HasIndex(e => e.StatusChangedAt)
             .HasFilter($"status IN ({(int)FailedMessageStatus.Resolved}, {(int)FailedMessageStatus.Archived})");
+
+        // Widen the group-aggregate indexes with covering INCLUDE columns so the
+        // /api/recoverability/groups/ aggregate is index-only (no key lookups / sequential scan with a
+        // residual status predicate). The IncludeProperties API is
+        // provider-specific, so the widening is applied here rather than in the shared configuration.
+        modelBuilder.Entity<FailedMessageEntity>()
+            .HasIndex(e => new { e.Status, e.LastModified })
+            .IncludeProperties(nameof(FailedMessageEntity.FirstTimeOfFailure), nameof(FailedMessageEntity.LastTimeOfFailure));
+
+        modelBuilder.Entity<FailedMessageGroupEntity>()
+            .HasIndex(e => new { e.Type, e.GroupId })
+            .IncludeProperties(nameof(FailedMessageGroupEntity.Title));
     }
 
     public override bool IsDuplicateKeyException(DbUpdateException exception)