perf: Analytics Phase 6 — Optimization & Cleanup (107MB RAM saved)

docs/analytics/phase6-optimization-and-cleanup.md

@@ -0,0 +1,139 @@
+# Phase 6: Optimization & Cleanup
+
+## PR
+[#31](https://github.com/Leddger-AI/LedgerAI/pull/31) — `feature/analytics-phase6` — **Open**
+
+## Overview
+
+Phase 6 optimizes server memory usage for the Render 512MB plan and cleans up dead code from the Firebase→Supabase migration. Three key changes reduce server RAM by ~107MB (49%) at startup.
+
+## Changes
+
+### 1. Lazy-load googleapis (`server/utils/emailService.js`)
+
+**Problem:** `googleapis` was loaded at module top-level via `const { google } = require('googleapis')`, consuming **62MB heap** at server startup — even if no emails were being sent.
+
+**Fix:** Replaced with a lazy-load helper function:
+```js
+function getOAuth2Client() {
+  const { google } = require('googleapis');
+  return google.auth.OAuth2;
+}
+```
+
+Now `googleapis` is only loaded when `createTransporter()` is actually called (i.e., when sending an email). The 62MB heap cost is deferred to first email send.
+
+**Impact:** Server startup heap drops from 101MB → 30MB.
+
+**Files already lazy-loading googleapis (no change needed):**
+- `server/index.js:1088` — `require('googleapis')` inside `buildTransporterFromAccount()`
+- `server/scheduler.js:59` — `require('googleapis')` inside scheduled email send
+- `server/startupCheck.js:83` — `require('googleapis')` inside `checkGmailOAuth2()`
+
+### 2. Remove dead User model (`server/index.js`)
+
+**Problem:** The MongoDB `User` model (`server/models/User.js`) used `firebaseUid` as its primary key — a leftover from the Firebase→Supabase migration (PR #12). Departments were migrated to Supabase's `profiles` table, making the `User` MongoDB model dead code. The only references were in two account-deletion endpoints.
+
+**Fix:** Removed `require('./models/User')` and `User.deleteMany({ firebaseUid: userId })` from both:
+- `DELETE /api/user/data` — reset user data
+- `DELETE /api/user/account` — permanently delete account
+
+These endpoints now only delete from Supabase + the 5 active MongoDB models (EmailAccount, EmailConfig, EmailDraft, EmailCampaign, Spreadsheet) + Cloudinary.
+
+**Note:** `server/models/User.js` file is left in place to avoid breaking any potential references, but it is no longer imported anywhere in production code.
+
+### 3. Code-split AnalyticsPage (`src/App.jsx`)
+
+**Problem:** `AnalyticsPage.jsx` was a static import, bundled into the main 5.95MB JS chunk even though most users never visit the analytics page.
+
+**Fix:** Changed to lazy import:
+```js
+const AnalyticsPage = lazy(() => import('./pages/AnalyticsPage.jsx'));
+```
+
+**Impact:**
+- New chunk: `AnalyticsPage-*.js` (21.7KB, gzipped 4.6KB)
+- Main bundle: 5,950KB → 5,927KB (−23KB)
+- Analytics page code only loads when user navigates to `/dashboard/template-analytics`
+
+### 4. Health monitoring endpoint (`server/index.js`)
+
+Added `GET /api/health` for Render monitoring:
+
+```json
+{
+  "status": "ok",
+  "uptime": 3600,
+  "memory": {
+    "rss": "113MB",
+    "heapUsed": "30MB",
+    "heapTotal": "61MB",
+    "external": "3MB"
+  }
+}
+```
+
+No auth required — safe to expose basic memory stats. Use for Render health checks and memory monitoring dashboards.
+
+---
+
+## Memory Benchmarks
+
+### Before Phase 6 (origin/main)
+
+| Metric | Value |
+|---|---|
+| RSS | 220MB |
+| Heap Used | 101MB |
+| Heap Total | 212MB |
+| External | 21MB |
+
+### After Phase 6
+
+| Metric | Value | Delta |
+|---|---|---|
+| RSS | **113MB** | **−107MB (−49%)** |
+| Heap Used | **30MB** | **−71MB (−70%)** |
+| Heap Total | **61MB** | **−151MB (−71%)** |
+| External | **3MB** | **−18MB** |
+
+### Render 512MB Plan Headroom
+
+| | Before | After |
+|---|---|---|
+| Server RSS | 220MB | 113MB |
+| Available for runtime growth | 292MB | **399MB** |
+| Status | Tight at scale | **Comfortable** |
+
+When googleapis loads on first email send, heap temporarily increases by ~62MB (30MB → ~92MB), still well within the 512MB limit.
+
+---
+
+## Frontend Bundle Comparison
+
+| Chunk | Before | After |
+|---|---|---|
+| Main bundle (`index-*.js`) | 5,950KB | 5,927KB |
+| AnalyticsPage chunk | — | 21.7KB (separate) |
+| AnalyticsPage CSS | — | 8.5KB (separate) |
+| Total dist | 7.3MB | 7.3MB |
+
+---
+
+## Files Changed
+
+| File | Change |
+|---|---|
+| `server/utils/emailService.js` | Lazy-load googleapis via `getOAuth2Client()` |
+| `server/index.js` | Remove dead User model refs, add `/api/health` endpoint |
+| `src/App.jsx` | Code-split AnalyticsPage as lazy route |
+
+---
+
+## Commits
+
+| # | Message |
+|---|---|
+| 1 | `perf(ram): lazy-load googleapis + remove dead User model + add health endpoint` |
+| 2 | `perf(frontend): code-split AnalyticsPage as lazy route` |
+| 3 | `docs: add Phase 6 optimization and cleanup documentation` |

server/index.js

@@ -60,6 +60,21 @@ const mongoConnectPromise = mongoose.connect(MONGODB_URI)
 // API ENDPOINTS
 // ==========================================
 
+// Health & memory monitoring (for Render 512MB plan)
+app.get('/api/health', (req, res) => {
+  const mem = process.memoryUsage();
+  res.json({
+    status: 'ok',
+    uptime: process.uptime(),
+    memory: {
+      rss: `${Math.round(mem.rss / 1024 / 1024)}MB`,
+      heapUsed: `${Math.round(mem.heapUsed / 1024 / 1024)}MB`,
+      heapTotal: `${Math.round(mem.heapTotal / 1024 / 1024)}MB`,
+      external: `${Math.round(mem.external / 1024 / 1024)}MB`,
+    },
+  });
+});
+
 // Helper: Ensure user profile exists in Supabase
 const getOrCreateUser = async (userId, email) => {
   const { data: existing } = await supabase
@@ -1945,11 +1960,6 @@ app.delete('/api/user/data', verifyToken, async (req, res) => {
       deleted.mongodb.push(`${name} (${result.deletedCount})`);
     }
 
-    // User model uses firebaseUid
-    const User = require('./models/User');
-    const userResult = await User.deleteMany({ firebaseUid: userId });
-    deleted.mongodb.push(`User (${userResult.deletedCount})`);
-
     // --- Cloudinary avatar deletion ---
     try {
       const cloudinary = configureCloudinary();
@@ -2002,10 +2012,6 @@ app.delete('/api/user/account', verifyToken, async (req, res) => {
       deleted.mongodb.push(`${name} (${result.deletedCount})`);
     }
 
-    const User = require('./models/User');
-    const userResult = await User.deleteMany({ firebaseUid: userId });
-    deleted.mongodb.push(`User (${userResult.deletedCount})`);
-
     try {
       const cloudinary = configureCloudinary();
       if (cloudinary) {

server/utils/emailService.js

@@ -1,10 +1,14 @@
 const nodemailer = require('nodemailer');
-const { google } = require('googleapis');
-const OAuth2 = google.auth.OAuth2;
+
+function getOAuth2Client() {
+  const { google } = require('googleapis');
+  return google.auth.OAuth2;
+}
 
 const createTransporter = async (emailConfig = null) => {
   if (emailConfig) {
     if (emailConfig.authMethod === 'oauth2') {
+      const OAuth2 = getOAuth2Client();
       const oauth2Client = new OAuth2(
         emailConfig.clientId,
         emailConfig.clientSecret,
@@ -50,6 +54,7 @@ const createTransporter = async (emailConfig = null) => {
   }
 
   // Fallback to env vars
+  const OAuth2 = getOAuth2Client();
   const oauth2Client = new OAuth2(
     process.env.GOOGLE_CLIENT_ID,
     process.env.GOOGLE_CLIENT_SECRET,

src/App.jsx

@@ -78,7 +78,6 @@ import MeetView from './MeetView.jsx';
 import ExportView from './ExportView.jsx';
 import EmailAutomationView from './EmailAutomationView.jsx';
 import AnalysisView from './AnalysisView.jsx';
-import AnalyticsPage from './pages/AnalyticsPage.jsx';
 import StudentTemplateBuilder from './pages/StudentTemplateBuilder.jsx';
 import EmployeeTemplateBuilder from './pages/EmployeeTemplateBuilder.jsx';
 import TeamTemplateBuilder from './pages/TeamTemplateBuilder.jsx';
@@ -114,6 +113,7 @@ const PrivacyPolicy = lazy(() => import('./pages/PrivacyPolicy.jsx'));
 const TermsOfService = lazy(() => import('./pages/TermsOfService.jsx'));
 const PublicFormView = lazy(() => import('./pages/PublicFormView.jsx'));
 const DraftsView = lazy(() => import('./pages/DraftsView.jsx'));
+const AnalyticsPage = lazy(() => import('./pages/AnalyticsPage.jsx'));
 
 
 // Pre-defined avatars from public sources