perf: Add database indexes and optimize queries for MVP

Performance improvements for local development:
- Add indexes: Agents.Name, Conversations.Title, AgentExecutions.CompletedAt, ConversationMessages.CreatedAt
- Remove redundant ConversationMessages index (covered by composite)
- Add .Take() limit to SendMessage context query to prevent fetching excessive history
- Downgrade Microsoft.Extensions.Http from 9.0.10 to 8.0.1 for .NET 8 compatibility

All query handlers already had .AsNoTracking() for read operations.

Impact: Faster search/filter operations even with 10-20 agents, prevents N+1 on long conversations.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

BACKEND/Codex.CQRS/Commands/SendMessageCommand.cs

@@ -200,6 +200,8 @@ public class SendMessageCommandHandler : ICommandHandler<SendMessageCommand, Sen
         var contextMessages = await _dbContext.ConversationMessages
             .AsNoTracking()
             .Where(m => m.ConversationId == conversation.Id && m.IsInActiveWindow)
+            .OrderByDescending(m => m.MessageIndex)
+            .Take(agent.ConversationWindowSize)
             .OrderBy(m => m.MessageIndex)
             .ToListAsync(cancellationToken);
 

BACKEND/Codex.Dal/Codex.Dal.csproj

@@ -13,7 +13,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="Microsoft.Extensions.Http" Version="9.0.10" />
+    <PackageReference Include="Microsoft.Extensions.Http" Version="8.0.1" />
     <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="8.0.11" />
     <PackageReference Include="OpenHarbor.CQRS" Version="8.1.0-rc1" />
     <PackageReference Include="OpenHarbor.CQRS.DynamicQuery.Abstractions" Version="8.1.0-rc1" />

BACKEND/Codex.Dal/CodexDbContext.cs

@@ -60,6 +60,7 @@ public class CodexDbContext : DbContext
         // Indexes
         entity.HasIndex(a => new { a.Status, a.IsDeleted });
         entity.HasIndex(a => a.Type);
+        entity.HasIndex(a => a.Name); // Performance: name searches
 
         // Relationships
         entity.HasMany(a => a.Tools)
@@ -125,6 +126,7 @@ public class CodexDbContext : DbContext
 
         entity.HasIndex(e => e.ConversationId);
         entity.HasIndex(e => e.Status);
+        entity.HasIndex(e => e.CompletedAt); // Performance: time-based queries
 
         // Relationships
         entity.HasOne(e => e.Conversation)
@@ -156,6 +158,7 @@ public class CodexDbContext : DbContext
         // Indexes
         entity.HasIndex(c => new { c.IsActive, c.LastMessageAt })
             .IsDescending(false, true); // IsActive ASC, LastMessageAt DESC
+        entity.HasIndex(c => c.Title); // Performance: title searches
 
         // Relationships
         entity.HasMany(c => c.Messages)
@@ -178,10 +181,10 @@ public class CodexDbContext : DbContext
         // Composite index for efficient conversation window queries
         entity.HasIndex(m => new { m.ConversationId, m.IsInActiveWindow, m.MessageIndex });
 
-        // Index for ordering messages
-        entity.HasIndex(m => new { m.ConversationId, m.MessageIndex });
-
         // Index for role filtering
         entity.HasIndex(m => m.Role);
+
+        // Performance: time-based queries
+        entity.HasIndex(m => m.CreatedAt);
     }
 }

BACKEND/Codex.Dal/Migrations/20251027032413_AddPerformanceIndexes.Designer.cs

@@ -0,0 +1,384 @@
+// <auto-generated />
+using System;
+using System.Text.Json;
+using Codex.Dal;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace Codex.Dal.Migrations
+{
+    [DbContext(typeof(CodexDbContext))]
+    [Migration("20251027032413_AddPerformanceIndexes")]
+    partial class AddPerformanceIndexes
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "8.0.11")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("Codex.Dal.Entities.Agent", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ApiKeyEncrypted")
+                        .HasColumnType("text");
+
+                    b.Property<int>("ConversationWindowSize")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Description")
+                        .IsRequired()
+                        .HasMaxLength(1000)
+                        .HasColumnType("character varying(1000)");
+
+                    b.Property<bool>("EnableMemory")
+                        .HasColumnType("boolean");
+
+                    b.Property<bool>("IsDeleted")
+                        .HasColumnType("boolean");
+
+                    b.Property<int>("MaxTokens")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("ModelEndpoint")
+                        .HasMaxLength(500)
+                        .HasColumnType("character varying(500)");
+
+                    b.Property<string>("ModelName")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<string>("ModelProvider")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<int>("ProviderType")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("SystemPrompt")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<double>("Temperature")
+                        .HasColumnType("double precision");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Name");
+
+                    b.HasIndex("Type");
+
+                    b.HasIndex("Status", "IsDeleted");
+
+                    b.ToTable("Agents");
+                });
+
+            modelBuilder.Entity("Codex.Dal.Entities.AgentExecution", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<Guid>("AgentId")
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTime?>("CompletedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid?>("ConversationId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ErrorMessage")
+                        .HasColumnType("text");
+
+                    b.Property<decimal?>("EstimatedCost")
+                        .HasPrecision(18, 6)
+                        .HasColumnType("numeric(18,6)");
+
+                    b.Property<long?>("ExecutionTimeMs")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Input")
+                        .HasColumnType("text");
+
+                    b.Property<int?>("InputTokens")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Output")
+                        .IsRequired()
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("text")
+                        .HasDefaultValue("");
+
+                    b.Property<int?>("OutputTokens")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTime>("StartedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("ToolCallResults")
+                        .HasColumnType("text");
+
+                    b.Property<string>("ToolCalls")
+                        .HasColumnType("text");
+
+                    b.Property<int?>("TotalTokens")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("UserPrompt")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CompletedAt");
+
+                    b.HasIndex("ConversationId");
+
+                    b.HasIndex("Status");
+
+                    b.HasIndex("AgentId", "StartedAt")
+                        .IsDescending(false, true);
+
+                    b.ToTable("AgentExecutions");
+                });
+
+            modelBuilder.Entity("Codex.Dal.Entities.AgentTool", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<Guid>("AgentId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ApiBaseUrl")
+                        .HasMaxLength(500)
+                        .HasColumnType("character varying(500)");
+
+                    b.Property<string>("ApiKeyEncrypted")
+                        .HasColumnType("text");
+
+                    b.Property<JsonDocument>("Configuration")
+                        .HasColumnType("jsonb");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<bool>("IsEnabled")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("McpAuthTokenEncrypted")
+                        .HasColumnType("text");
+
+                    b.Property<string>("McpServerUrl")
+                        .HasMaxLength(500)
+                        .HasColumnType("character varying(500)");
+
+                    b.Property<string>("ToolName")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Type");
+
+                    b.HasIndex("AgentId", "IsEnabled");
+
+                    b.ToTable("AgentTools");
+                });
+
+            modelBuilder.Entity("Codex.Dal.Entities.Conversation", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<bool>("IsActive")
+                        .HasColumnType("boolean");
+
+                    b.Property<DateTime>("LastMessageAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("MessageCount")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTime>("StartedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Summary")
+                        .HasMaxLength(2000)
+                        .HasColumnType("character varying(2000)");
+
+                    b.Property<string>("Title")
+                        .IsRequired()
+                        .HasMaxLength(500)
+                        .HasColumnType("character varying(500)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Title");
+
+                    b.HasIndex("IsActive", "LastMessageAt")
+                        .IsDescending(false, true);
+
+                    b.ToTable("Conversations");
+                });
+
+            modelBuilder.Entity("Codex.Dal.Entities.ConversationMessage", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Content")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<Guid>("ConversationId")
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid?>("ExecutionId")
+                        .HasColumnType("uuid");
+
+                    b.Property<bool>("IsInActiveWindow")
+                        .HasColumnType("boolean");
+
+                    b.Property<int>("MessageIndex")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Role")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("TokenCount")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("ToolCalls")
+                        .HasColumnType("text");
+
+                    b.Property<string>("ToolResults")
+                        .HasColumnType("text");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CreatedAt");
+
+                    b.HasIndex("ExecutionId");
+
+                    b.HasIndex("Role");
+
+                    b.HasIndex("ConversationId", "IsInActiveWindow", "MessageIndex");
+
+                    b.ToTable("ConversationMessages");
+                });
+
+            modelBuilder.Entity("Codex.Dal.Entities.AgentExecution", b =>
+                {
+                    b.HasOne("Codex.Dal.Entities.Agent", "Agent")
+                        .WithMany("Executions")
+                        .HasForeignKey("AgentId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Codex.Dal.Entities.Conversation", "Conversation")
+                        .WithMany("Executions")
+                        .HasForeignKey("ConversationId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.Navigation("Agent");
+
+                    b.Navigation("Conversation");
+                });
+
+            modelBuilder.Entity("Codex.Dal.Entities.AgentTool", b =>
+                {
+                    b.HasOne("Codex.Dal.Entities.Agent", "Agent")
+                        .WithMany("Tools")
+                        .HasForeignKey("AgentId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Agent");
+                });
+
+            modelBuilder.Entity("Codex.Dal.Entities.ConversationMessage", b =>
+                {
+                    b.HasOne("Codex.Dal.Entities.Conversation", "Conversation")
+                        .WithMany("Messages")
+                        .HasForeignKey("ConversationId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Codex.Dal.Entities.AgentExecution", "Execution")
+                        .WithMany("Messages")
+                        .HasForeignKey("ExecutionId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.Navigation("Conversation");
+
+                    b.Navigation("Execution");
+                });
+
+            modelBuilder.Entity("Codex.Dal.Entities.Agent", b =>
+                {
+                    b.Navigation("Executions");
+
+                    b.Navigation("Tools");
+                });
+
+            modelBuilder.Entity("Codex.Dal.Entities.AgentExecution", b =>
+                {
+                    b.Navigation("Messages");
+                });
+
+            modelBuilder.Entity("Codex.Dal.Entities.Conversation", b =>
+                {
+                    b.Navigation("Executions");
+
+                    b.Navigation("Messages");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

BACKEND/Codex.Dal/Migrations/20251027032413_AddPerformanceIndexes.cs

@@ -0,0 +1,63 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Codex.Dal.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddPerformanceIndexes : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropIndex(
+                name: "IX_ConversationMessages_ConversationId_MessageIndex",
+                table: "ConversationMessages");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Conversations_Title",
+                table: "Conversations",
+                column: "Title");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_ConversationMessages_CreatedAt",
+                table: "ConversationMessages",
+                column: "CreatedAt");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Agents_Name",
+                table: "Agents",
+                column: "Name");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_AgentExecutions_CompletedAt",
+                table: "AgentExecutions",
+                column: "CompletedAt");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropIndex(
+                name: "IX_Conversations_Title",
+                table: "Conversations");
+
+            migrationBuilder.DropIndex(
+                name: "IX_ConversationMessages_CreatedAt",
+                table: "ConversationMessages");
+
+            migrationBuilder.DropIndex(
+                name: "IX_Agents_Name",
+                table: "Agents");
+
+            migrationBuilder.DropIndex(
+                name: "IX_AgentExecutions_CompletedAt",
+                table: "AgentExecutions");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_ConversationMessages_ConversationId_MessageIndex",
+                table: "ConversationMessages",
+                columns: new[] { "ConversationId", "MessageIndex" });
+        }
+    }
+}

BACKEND/Codex.Dal/Migrations/CodexDbContextModelSnapshot.cs

@@ -92,6 +92,8 @@ namespace Codex.Dal.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("Name");
+
                     b.HasIndex("Type");
 
                     b.HasIndex("Status", "IsDeleted");
@@ -160,6 +162,8 @@ namespace Codex.Dal.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("CompletedAt");
+
                     b.HasIndex("ConversationId");
 
                     b.HasIndex("Status");
@@ -248,6 +252,8 @@ namespace Codex.Dal.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("Title");
+
                     b.HasIndex("IsActive", "LastMessageAt")
                         .IsDescending(false, true);
 
@@ -293,12 +299,12 @@ namespace Codex.Dal.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("CreatedAt");
+
                     b.HasIndex("ExecutionId");
 
                     b.HasIndex("Role");
 
-                    b.HasIndex("ConversationId", "MessageIndex");
-
                     b.HasIndex("ConversationId", "IsInActiveWindow", "MessageIndex");
 
                     b.ToTable("ConversationMessages");