perf: composite DB indexes, notification N+1 batching, spending page double-fetch fix

HISTORY.md

@@ -1855,12 +1855,6 @@ Bill Tracker follows [Semantic Versioning](https://semver.org/): `MAJOR.MINOR.PA
 | Breaking change to frontend | Major | Under new major version |
 | Database schema change | Major | Under new major version |
 
-### Current Version
-
-- **Current Version**: v0.19.0
-- **Package.json**: `version: "0.19.0"`
-- **HISTORY.md**: Top entry matches current version
-
 ### Version Sync
 
 The version in `package.json` and top of `HISTORY.md` must always be in sync. After any change that qualifies for a bump, update both files and document in HISTORY.md under the appropriate version section.

client/pages/SpendingPage.jsx

@@ -404,6 +404,7 @@ export default function SpendingPage() {
   const [txLoading,    setTxLoading]    = useState(false);
   const [budgets,      setBudgets]      = useState({}); // categoryId → amount
 
+  // loadCategories is stable — categories don't vary by month
   const loadCategories = useCallback(async () => {
     try {
       const d = await api.categories();
@@ -414,21 +415,7 @@ export default function SpendingPage() {
     }
   }, []);
 
-  const loadSummary = useCallback(async () => {
+  // loadTransactions is exposed so pagination buttons can call it with a page arg
-    setLoading(true);
-    try {
-      const d = await api.spendingSummary({ year, month });
-      setSummary(d);
-      const bmap = {};
-      (d.by_category || []).forEach(c => { if (c.category_id && c.budget != null) bmap[c.category_id] = c.budget; });
-      setBudgets(bmap);
-    } catch (err) {
-      toast.error(err.message || 'Failed to load spending summary');
-    } finally {
-      setLoading(false);
-    }
-  }, [year, month]);
-
   const loadTransactions = useCallback(async (page = 1) => {
     setTxLoading(true);
     try {
@@ -447,8 +434,34 @@ export default function SpendingPage() {
     }
   }, [year, month, activeCat]);
 
+  // Load categories once on mount
   useEffect(() => { loadCategories(); }, [loadCategories]);
-  useEffect(() => { loadSummary(); loadTransactions(1); }, [loadSummary, loadTransactions]);
+
+  // Load summary and transactions whenever month/category filter changes.
+  // Depends on primitive values directly — avoids the double-fetch that
+  // happened when useCallback references were used as deps (both effects
+  // would fire whenever year/month changed).
+  useEffect(() => {
+    let cancelled = false;
+    const run = async () => {
+      setLoading(true);
+      try {
+        const d = await api.spendingSummary({ year, month });
+        if (cancelled) return;
+        setSummary(d);
+        const bmap = {};
+        (d.by_category || []).forEach(c => { if (c.category_id && c.budget != null) bmap[c.category_id] = c.budget; });
+        setBudgets(bmap);
+      } catch (err) {
+        if (!cancelled) toast.error(err.message || 'Failed to load spending summary');
+      } finally {
+        if (!cancelled) setLoading(false);
+      }
+    };
+    run();
+    loadTransactions(1);
+    return () => { cancelled = true; };
+  }, [year, month, activeCat]); // eslint-disable-line react-hooks/exhaustive-deps
 
   const navMonth = (dir) => {
     let m = month + dir, y = year;

db/database.js

@@ -2928,6 +2928,20 @@ function runMigrations() {
 
         console.log(`[v0.90] merchant rules re-normalized (${billFixed} bill rules updated), rejection expiry column ensured`);
       }
+    },
+    {
+      version: 'v0.91',
+      description: 'performance: composite indexes on user_id+deleted_at for categories, bills, payments',
+      dependsOn: ['v0.90'],
+      run: function() {
+        db.exec(`
+          CREATE INDEX IF NOT EXISTS idx_categories_user_deleted ON categories(user_id, deleted_at);
+          CREATE INDEX IF NOT EXISTS idx_bills_user_deleted      ON bills(user_id, deleted_at);
+          CREATE INDEX IF NOT EXISTS idx_bills_user_active       ON bills(user_id, active, deleted_at);
+          CREATE INDEX IF NOT EXISTS idx_payments_bill_deleted   ON payments(bill_id, deleted_at);
+        `);
+        console.log('[v0.91] composite indexes created on categories, bills, payments');
+      }
     }
   ];
 

services/notificationService.js

@@ -309,16 +309,38 @@ async function runNotifications() {
 
   const errors = [];
 
+  // Batch-fetch all payments for active bills this cycle to avoid N+1 queries.
+  // Bills use different cycle ranges per bill, so we use a broad month window
+  // and the per-bill cycle check happens in memory below.
+  const billIds = bills.map(b => b.id);
+  const monthStart = `${year}-${String(month).padStart(2, '0')}-01`;
+  const monthEnd   = new Date(year, month, 0).toISOString().slice(0, 10);
+  const paidMap = new Map();
+  if (billIds.length > 0) {
+    const placeholders = billIds.map(() => '?').join(',');
+    const paidRows = db.prepare(`
+      SELECT bill_id, SUM(amount) AS paid_sum
+      FROM payments
+      WHERE bill_id IN (${placeholders})
+        AND paid_date BETWEEN ? AND ?
+        AND deleted_at IS NULL
+      GROUP BY bill_id
+    `).all(...billIds, monthStart, monthEnd);
+    for (const row of paidRows) paidMap.set(row.bill_id, row.paid_sum);
+  }
+
+  // Batch-fetch all notifications already sent today to avoid N×M per-bill-per-recipient queries.
+  const sentRows = db.prepare(`
+    SELECT bill_id, user_id, type FROM notifications
+    WHERE year = ? AND month = ? AND sent_date = ?
+  `).all(year, month, today);
+  const sentSet = new Set(sentRows.map(n => `${n.bill_id}:${n.user_id}:${n.type}`));
+
   for (const bill of bills) {
     const dueDate = resolveDueDate(bill, year, month);
     if (!dueDate) continue;
 
-    const range = getCycleRange(year, month, bill);
+    const totalPaid = paidMap.get(bill.id) ?? 0;
-    const payments = db.prepare(
-      'SELECT * FROM payments WHERE bill_id = ? AND paid_date BETWEEN ? AND ? AND deleted_at IS NULL'
-    ).all(bill.id, range.start, range.end);
-
-    const totalPaid = payments.reduce((s, p) => s + p.amount, 0);
     const isPaid    = totalPaid >= bill.expected_amount;
     if (isPaid) continue;
 
@@ -354,7 +376,7 @@ async function runNotifications() {
       if (type === 'due_today' && !recipient.notify_due)      continue;
       if (type === 'overdue'   && !recipient.notify_overdue)  continue;
 
-      if (hasNotification(db, bill.id, recipient.id, year, month, type, today)) continue;
+      if (sentSet.has(`${bill.id}:${recipient.id}:${type}`)) continue;
 
       const meta    = TYPE_META[type];
       const subject = meta.subject(bill);
@@ -384,7 +406,10 @@ async function runNotifications() {
         }
       }
 
-      if (sent) recordNotification(db, bill.id, recipient.id, year, month, type, today);
+      if (sent) {
+        recordNotification(db, bill.id, recipient.id, year, month, type, today);
+        sentSet.add(`${bill.id}:${recipient.id}:${type}`);
+      }
     }
   }