From 764728759dd0b2e502333124c784ffe4b7f08d57 Mon Sep 17 00:00:00 2001
From: darbs-claude <developers@lethean.io>
Date: Mon, 23 Feb 2026 06:29:14 +0000
Subject: [PATCH] fix: add missing database indexes (closes #21)

- Verify agent_sessions.session_id: unique() constraint creates an
  implicit unique index (agent_sessions_session_id_unique) which is
  sufficient for string lookups; no additional index required
- Drop redundant agent_plans_slug_index: the unique() constraint on
  slug already provides agent_plans_slug_unique covering all lookups
- Add compound (workspace_id, slug) index on agent_plans for the
  common routing pattern WHERE workspace_id = ? AND slug = ?
- Verify agent_workspace_states.key: already indexed via ->index('key')
  in migration 000003; no additional index required
- Mark DB-002 as resolved in TODO.md

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 ...1_01_01_000005_add_performance_indexes.php | 51 +++++++++++++++++++
 TODO.md                                       |  9 ++--
 2 files changed, 56 insertions(+), 4 deletions(-)
 create mode 100644 Migrations/0001_01_01_000005_add_performance_indexes.php

diff --git a/Migrations/0001_01_01_000005_add_performance_indexes.php b/Migrations/0001_01_01_000005_add_performance_indexes.php
new file mode 100644
index 0000000..b3c2571
--- /dev/null
+++ b/Migrations/0001_01_01_000005_add_performance_indexes.php
@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Add performance indexes for frequently queried columns (DB-002).
+     *
+     * Analysis per acceptance criteria:
+     * - agent_sessions.session_id: the ->unique() constraint in migration 000001
+     *   creates a unique index (agent_sessions_session_id_unique) which the query
+     *   optimiser uses for string lookups. No additional index required.
+     * - agent_plans.slug: ->unique() already creates agent_plans_slug_unique; the
+     *   plain agent_plans_slug_index added separately is redundant and is dropped.
+     *   A compound (workspace_id, slug) index is added for the common routing
+     *   pattern: WHERE workspace_id = ? AND slug = ?
+     * - agent_workspace_states.key: already indexed via ->index('key') in
+     *   migration 000003. No additional index required.
+     */
+    public function up(): void
+    {
+        if (Schema::hasTable('agent_plans')) {
+            Schema::table('agent_plans', function (Blueprint $table) {
+                // Drop the redundant plain slug index. The unique constraint on slug
+                // already provides agent_plans_slug_unique, which covers all lookup queries.
+                $table->dropIndex('agent_plans_slug_index');
+
+                // Compound index for the common routing pattern:
+                // AgentPlan::where('workspace_id', $id)->where('slug', $slug)->first()
+                $table->index(['workspace_id', 'slug'], 'agent_plans_workspace_slug_index');
+            });
+        }
+    }
+
+    public function down(): void
+    {
+        if (Schema::hasTable('agent_plans')) {
+            Schema::table('agent_plans', function (Blueprint $table) {
+                $table->dropIndex('agent_plans_workspace_slug_index');
+
+                // Restore the redundant slug index that was present before this migration.
+                $table->index('slug');
+            });
+        }
+    }
+};
diff --git a/TODO.md b/TODO.md
index 81421a8..d6fed66 100644
--- a/TODO.md
+++ b/TODO.md
@@ -92,10 +92,10 @@ Production-quality task list for the AI agent orchestration package.
   - Adds `agent_plan_id` FK and related columns to `agent_sessions`
   - Includes proper indexes for slug, workspace, and status queries
 
-- [ ] **DB-002: Missing indexes on frequently queried columns**
-  - `agent_sessions.session_id` - frequently looked up by string
-  - `agent_plans.slug` - used in URL routing
-  - `workspace_states.key` - key lookup is common operation
+- [x] **DB-002: Missing indexes on frequently queried columns** (FIXED 2026-02-23)
+  - `agent_sessions.session_id` - unique() constraint creates implicit index; sufficient for lookups
+  - `agent_plans.slug` - redundant plain index dropped; compound (workspace_id, slug) index added
+  - `workspace_states.key` - already indexed via ->index('key') in migration 000003
 
 ### Error Handling
 
@@ -287,6 +287,7 @@ Production-quality task list for the AI agent orchestration package.
 ### Database (Fixed)
 
 - [x] DB-001: Missing agent_plans migration - Created 0001_01_01_000003_create_agent_plans_tables.php (2026-01-29)
+- [x] DB-002: Performance indexes - Dropped redundant slug index, added compound (workspace_id, slug) index (2026-02-23)
 
 ---
 
-- 
2.45.3