perf: add TTL cache layer + rewrite bulk-health to single-query

- Add TTLCache class with hit/miss tracking - Cache all expensive endpoints: - analytics/* endpoints: 60s TTL - channels: 30s TTL - channels/:hash/messages: 15s TTL - nodes/:pubkey: 30s TTL - nodes/:pubkey/health: 30s TTL - observers: 30s TTL - bulk-health: 60s TTL - Invalidate all caches on new packet ingestion (POST + MQTT) - Rewrite bulk-health from N×5 queries to 1 query + JS matching - Add cache stats (size, hits, misses, hitRate) to /api/perf
feat: add frontend API response caching with TTL, in-flight dedup, and WebSocket invalidation
2026-03-31 08:45:40 +00:00 · 2026-03-20 02:06:23 +00:00 · 2026-03-20 02:03:25 +00:00 · 2026-03-20 01:49:19 +00:00
11 changed files with 250 additions and 98 deletions
--- a/public/analytics.js
+++ b/public/analytics.js
@@ -101,10 +101,10 @@
    try {
      _analyticsData = {};
      const [hashData, rfData, topoData, chanData] = await Promise.all([
-        api('/analytics/hash-sizes'),
-        api('/analytics/rf'),
-        api('/analytics/topology'),
-        api('/analytics/channels'),
+        api('/analytics/hash-sizes', { ttl: 60000 }),
+        api('/analytics/rf', { ttl: 60000 }),
+        api('/analytics/topology', { ttl: 60000 }),
+        api('/analytics/channels', { ttl: 60000 }),
      ]);
      _analyticsData = { hashData, rfData, topoData, chanData };
      renderTab('overview');
@@ -747,7 +747,7 @@
      </div>
    `;
    let allNodes = [];
-    try { const nd = await api('/nodes?limit=2000'); allNodes = nd.nodes || []; } catch {}
+    try { const nd = await api('/nodes?limit=2000', { ttl: 10000 }); allNodes = nd.nodes || []; } catch {}
    renderHashMatrix(data.topHops, allNodes);
    renderCollisions(data.topHops, allNodes);
  }
@@ -938,10 +938,10 @@
    el.innerHTML = '<div class="text-center text-muted" style="padding:40px">Analyzing route patterns…</div>';
    try {
      const [d2, d3, d4, d5] = await Promise.all([
-        api('/analytics/subpaths?minLen=2&maxLen=2&limit=50'),
-        api('/analytics/subpaths?minLen=3&maxLen=3&limit=30'),
-        api('/analytics/subpaths?minLen=4&maxLen=4&limit=20'),
-        api('/analytics/subpaths?minLen=5&maxLen=8&limit=15')
+        api('/analytics/subpaths?minLen=2&maxLen=2&limit=50', { ttl: 60000 }),
+        api('/analytics/subpaths?minLen=3&maxLen=3&limit=30', { ttl: 60000 }),
+        api('/analytics/subpaths?minLen=4&maxLen=4&limit=20', { ttl: 60000 }),
+        api('/analytics/subpaths?minLen=5&maxLen=8&limit=15', { ttl: 60000 })
      ]);

      function renderTable(data, title) {
@@ -1032,7 +1032,7 @@
    panel.classList.remove('collapsed');
    panel.innerHTML = '<div class="text-center text-muted" style="padding:40px">Loading…</div>';
    try {
-      const data = await api('/analytics/subpath-detail?hops=' + encodeURIComponent(hopsStr));
+      const data = await api('/analytics/subpath-detail?hops=' + encodeURIComponent(hopsStr), { ttl: 60000 });
      renderSubpathDetail(panel, data);
    } catch (e) {
      panel.innerHTML = `<div class="text-muted">Error: ${e.message}</div>`;
@@ -1141,9 +1141,9 @@
    el.innerHTML = '<div style="padding:40px;text-align:center;color:var(--text-muted)">Loading node analytics…</div>';
    try {
      const [nodesResp, bulkHealth, netStatus] = await Promise.all([
-        api('/nodes?limit=200&sortBy=lastSeen'),
-        api('/nodes/bulk-health?limit=50'),
-        api('/nodes/network-status')
+        api('/nodes?limit=200&sortBy=lastSeen', { ttl: 10000 }),
+        api('/nodes/bulk-health?limit=50', { ttl: 60000 }),
+        api('/nodes/network-status', { ttl: 60000 })
      ]);
      const nodes = nodesResp.nodes || nodesResp;
      const myNodes = JSON.parse(localStorage.getItem('meshcore-my-nodes') || '[]');
--- a/public/app.js
+++ b/public/app.js
@@ -11,19 +11,45 @@ function payloadTypeName(n) { return PAYLOAD_TYPES[n] || 'UNKNOWN'; }
 function payloadTypeColor(n) { return PAYLOAD_COLORS[n] || 'unknown'; }

 // --- Utilities ---
-const _apiPerf = { calls: 0, totalMs: 0, log: [] };
-async function api(path) {
+const _apiPerf = { calls: 0, totalMs: 0, log: [], cacheHits: 0 };
+const _apiCache = new Map();
+const _inflight = new Map();
+async function api(path, { ttl = 0, bust = false } = {}) {
  const t0 = performance.now();
-  const res = await fetch('/api' + path);
-  if (!res.ok) throw new Error(`API ${res.status}: ${path}`);
-  const data = await res.json();
-  const ms = performance.now() - t0;
-  _apiPerf.calls++;
-  _apiPerf.totalMs += ms;
-  _apiPerf.log.push({ path, ms: Math.round(ms), time: Date.now() });
-  if (_apiPerf.log.length > 200) _apiPerf.log.shift();
-  if (ms > 500) console.warn(`[SLOW API] ${path} took ${Math.round(ms)}ms`);
-  return data;
+  if (!bust && ttl > 0) {
+    const cached = _apiCache.get(path);
+    if (cached && Date.now() < cached.expires) {
+      _apiPerf.calls++;
+      _apiPerf.cacheHits++;
+      _apiPerf.log.push({ path, ms: 0, time: Date.now(), cached: true });
+      if (_apiPerf.log.length > 200) _apiPerf.log.shift();
+      return cached.data;
+    }
+  }
+  // Deduplicate in-flight requests
+  if (_inflight.has(path)) return _inflight.get(path);
+  const promise = (async () => {
+    const res = await fetch('/api' + path);
+    if (!res.ok) throw new Error(`API ${res.status}: ${path}`);
+    const data = await res.json();
+    const ms = performance.now() - t0;
+    _apiPerf.calls++;
+    _apiPerf.totalMs += ms;
+    _apiPerf.log.push({ path, ms: Math.round(ms), time: Date.now() });
+    if (_apiPerf.log.length > 200) _apiPerf.log.shift();
+    if (ms > 500) console.warn(`[SLOW API] ${path} took ${Math.round(ms)}ms`);
+    if (ttl > 0) _apiCache.set(path, { data, expires: Date.now() + ttl });
+    return data;
+  })();
+  _inflight.set(path, promise);
+  promise.finally(() => _inflight.delete(path));
+  return promise;
+}
+
+function invalidateApiCache(prefix) {
+  for (const key of _apiCache.keys()) {
+    if (key.startsWith(prefix || '')) _apiCache.delete(key);
+  }
 }
 // Expose for console debugging: apiPerf()
 window.apiPerf = function() {
@@ -39,7 +65,9 @@ window.apiPerf = function() {
    totalMs: Math.round(s.totalMs)
  })).sort((a, b) => b.totalMs - a.totalMs);
  console.table(rows);
-  return { calls: _apiPerf.calls, avgMs: Math.round(_apiPerf.totalMs / _apiPerf.calls), endpoints: rows };
+  const hitRate = _apiPerf.calls ? Math.round(_apiPerf.cacheHits / _apiPerf.calls * 100) : 0;
+  console.log(`Cache: ${_apiPerf.cacheHits} hits / ${_apiPerf.calls} calls (${hitRate}% hit rate)`);
+  return { calls: _apiPerf.calls, avgMs: Math.round(_apiPerf.totalMs / (_apiPerf.calls - _apiPerf.cacheHits || 1)), cacheHits: _apiPerf.cacheHits, hitRate: hitRate + '%', endpoints: rows };
 };

 function timeAgo(iso) {
@@ -165,6 +193,10 @@ function connectWS() {
  ws.onmessage = (e) => {
    try {
      const msg = JSON.parse(e.data);
+      // Invalidate caches when new data arrives
+      invalidateApiCache('/stats');
+      invalidateApiCache('/nodes');
+      invalidateApiCache('/channels');
      wsListeners.forEach(fn => fn(msg));
    } catch {}
  };
@@ -318,7 +350,7 @@ window.addEventListener('DOMContentLoaded', () => {
    favDropdown.innerHTML = '<div class="fav-dd-loading">Loading...</div>';
    const items = await Promise.all(favs.map(async (pk) => {
      try {
-        const h = await api('/nodes/' + pk + '/health');
+        const h = await api('/nodes/' + pk + '/health', { ttl: 30000 });
        const age = h.stats.lastHeard ? Date.now() - new Date(h.stats.lastHeard).getTime() : null;
        const status = age === null ? '🔴' : age < 3600000 ? '🟢' : age < 86400000 ? '🟡' : '🔴';
        return '<a href="#/nodes/' + pk + '" class="fav-dd-item" data-key="' + pk + '">'
@@ -422,7 +454,7 @@ window.addEventListener('DOMContentLoaded', () => {
  // --- Nav Stats ---
  async function updateNavStats() {
    try {
-      const stats = await api('/stats');
+      const stats = await api('/stats', { ttl: 5000 });
      const el = document.getElementById('navStats');
      if (el) {
        el.innerHTML = `<span class="stat-val">${stats.totalPackets}</span> pkts · <span class="stat-val">${stats.totalNodes}</span> nodes · <span class="stat-val">${stats.totalObservers}</span> obs`;
--- a/public/channels.js
+++ b/public/channels.js
@@ -18,7 +18,7 @@
      if (cached && !cached.fetchedAt) return cached; // legacy null entries
    }
    try {
-      const data = await api('/nodes/search?q=' + encodeURIComponent(name));
+      const data = await api('/nodes/search?q=' + encodeURIComponent(name), { ttl: 10000 });
      // Try exact match first, then case-insensitive, then contains
      const nodes = data.nodes || [];
      const match = nodes.find(n => n.name === name)
@@ -110,7 +110,7 @@
    }

    try {
-      const detail = await api('/nodes/' + encodeURIComponent(node.public_key));
+      const detail = await api('/nodes/' + encodeURIComponent(node.public_key), { ttl: 15000 });
      const n = detail.node;
      const adverts = detail.recentAdverts || [];
      const role = n.is_repeater ? '📡 Repeater' : n.is_room ? '🏠 Room' : n.is_sensor ? '🌡 Sensor' : '📻 Companion';
@@ -389,7 +389,7 @@

  async function loadChannels(silent) {
    try {
-      const data = await api('/channels');
+      const data = await api('/channels', { ttl: 15000 });
      channels = (data.channels || []).sort((a, b) => (b.lastActivity || '').localeCompare(a.lastActivity || ''));
      renderChannelList();
    } catch (e) {
@@ -451,7 +451,7 @@
    msgEl.innerHTML = '<div class="ch-loading">Loading messages…</div>';

    try {
-      const data = await api(`/channels/${hash}/messages?limit=200`);
+      const data = await api(`/channels/${hash}/messages?limit=200`, { ttl: 10000 });
      messages = data.messages || [];
      renderMessages();
      scrollToBottom();
@@ -466,7 +466,7 @@
    if (!msgEl) return;
    const wasAtBottom = msgEl.scrollHeight - msgEl.scrollTop - msgEl.clientHeight < 60;
    try {
-      const data = await api(`/channels/${selectedHash}/messages?limit=200`);
+      const data = await api(`/channels/${selectedHash}/messages?limit=200`, { ttl: 10000 });
      const newMsgs = data.messages || [];
      // #92: Use message ID/hash for change detection instead of count + timestamp
      var _getLastId = function (arr) { var m = arr.length ? arr[arr.length - 1] : null; return m ? (m.id || m.packetId || m.timestamp || '') : ''; };
--- a/public/home.js
+++ b/public/home.js
@@ -146,7 +146,7 @@
      if (!q) { suggest.classList.remove('open'); input.setAttribute('aria-expanded', 'false'); input.setAttribute('aria-activedescendant', ''); return; }
      searchTimeout = setTimeout(async () => {
        try {
-          const data = await api('/nodes/search?q=' + encodeURIComponent(q));
+          const data = await api('/nodes/search?q=' + encodeURIComponent(q), { ttl: 10000 });
          const nodes = data.nodes || [];
          if (!nodes.length) {
            suggest.innerHTML = '<div class="suggest-empty">No nodes found</div>';
@@ -247,7 +247,7 @@

    const cards = await Promise.all(myNodes.map(async (mn) => {
      try {
-        const h = await api('/nodes/' + encodeURIComponent(mn.pubkey) + '/health');
+        const h = await api('/nodes/' + encodeURIComponent(mn.pubkey) + '/health', { ttl: 30000 });
        const node = h.node || {};
        const stats = h.stats || {};
        const obs = h.observers || [];
@@ -369,7 +369,7 @@
  // ==================== STATS ====================
  async function loadStats() {
    try {
-      const s = await api('/stats');
+      const s = await api('/stats', { ttl: 5000 });
      const el = document.getElementById('homeStats');
      if (!el) return;
      el.innerHTML = `
@@ -391,7 +391,7 @@
    if (journey) journey.classList.remove('visible');

    try {
-      const h = await api('/nodes/' + encodeURIComponent(pubkey) + '/health');
+      const h = await api('/nodes/' + encodeURIComponent(pubkey) + '/health', { ttl: 30000 });
      const node = h.node || {};
      const stats = h.stats || {};
      const packets = h.recentPackets || [];
--- a/public/index.html
+++ b/public/index.html
@@ -76,17 +76,17 @@
  <main id="app" role="main"></main>

  <script src="vendor/qrcode.js"></script>
-  <script src="app.js?v=1773970465"></script>
-  <script src="home.js?v=1774079160"></script>
-  <script src="packets.js?v=1773969349"></script>
-  <script src="map.js?v=1774079160" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="channels.js?v=1774079160" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="nodes.js?v=1773961950" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="traces.js?v=1774079160" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="analytics.js?v=1773961035" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="app.js?v=1773972187"></script>
+  <script src="home.js?v=1773972187"></script>
+  <script src="packets.js?v=1773972187"></script>
+  <script src="map.js?v=1773972187" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="channels.js?v=1773972187" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="nodes.js?v=1773972187" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="traces.js?v=1773972187" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="analytics.js?v=1773972187" onerror="console.error('Failed to load:', this.src)"></script>
  <script src="live.js?v=1773964458" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="observers.js?v=1774079160" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="node-analytics.js?v=1773961276" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="observers.js?v=1773972187" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="node-analytics.js?v=1773972187" onerror="console.error('Failed to load:', this.src)"></script>
  <script src="perf.js?v=1" onerror="console.error('Failed to load:', this.src)"></script>
 </body>
 </html>
--- a/public/map.js
+++ b/public/map.js
@@ -245,12 +245,12 @@

  async function loadNodes() {
    try {
-      const data = await api(`/nodes?limit=10000&lastHeard=${filters.lastHeard}`);
+      const data = await api(`/nodes?limit=10000&lastHeard=${filters.lastHeard}`, { ttl: 10000 });
      nodes = data.nodes || [];
      buildRoleChecks(data.counts || {});

      // Load observers for jump buttons
-      const obsData = await api('/observers');
+      const obsData = await api('/observers', { ttl: 30000 });
      observers = obsData.observers || [];
      buildJumpButtons();

--- a/public/node-analytics.js
+++ b/public/node-analytics.js
@@ -40,7 +40,7 @@

    let data;
    try {
-      data = await api('/nodes/' + encodeURIComponent(pubkey) + '/analytics?days=' + days);
+      data = await api('/nodes/' + encodeURIComponent(pubkey) + '/analytics?days=' + days, { ttl: 60000 });
    } catch (e) {
      container.innerHTML = '<div style="padding:40px;text-align:center;color:#ff6b6b">Failed to load analytics: ' + escapeHtml(e.message) + '</div>';
      return;
--- a/public/nodes.js
+++ b/public/nodes.js
@@ -85,8 +85,8 @@
    const body = document.getElementById('nodeFullBody');
    try {
      const [nodeData, healthData] = await Promise.all([
-        api('/nodes/' + encodeURIComponent(pubkey)),
-        api('/nodes/' + encodeURIComponent(pubkey) + '/health').catch(() => null)
+        api('/nodes/' + encodeURIComponent(pubkey), { ttl: 15000 }),
+        api('/nodes/' + encodeURIComponent(pubkey) + '/health', { ttl: 30000 }).catch(() => null)
      ]);
      const n = nodeData.node;
      const adverts = nodeData.recentAdverts || [];
@@ -228,7 +228,7 @@
      if (activeTab !== 'all') params.set('role', activeTab);
      if (search) params.set('search', search);
      if (lastHeard) params.set('lastHeard', lastHeard);
-      const data = await api('/nodes?' + params);
+      const data = await api('/nodes?' + params, { ttl: 10000 });
      nodes = data.nodes || [];
      counts = data.counts || {};

@@ -238,7 +238,7 @@
      const missing = myNodes.filter(mn => !existingKeys.has(mn.pubkey));
      if (missing.length) {
        const fetched = await Promise.allSettled(
-          missing.map(mn => api('/nodes/' + encodeURIComponent(mn.pubkey)))
+          missing.map(mn => api('/nodes/' + encodeURIComponent(mn.pubkey), { ttl: 15000 }))
        );
        fetched.forEach(r => {
          if (r.status === 'fulfilled' && r.value && r.value.public_key) nodes.push(r.value);
@@ -401,8 +401,8 @@

    try {
      const [data, healthData] = await Promise.all([
-        api('/nodes/' + encodeURIComponent(pubkey)),
-        api('/nodes/' + encodeURIComponent(pubkey) + '/health').catch(() => null)
+        api('/nodes/' + encodeURIComponent(pubkey), { ttl: 15000 }),
+        api('/nodes/' + encodeURIComponent(pubkey) + '/health', { ttl: 30000 }).catch(() => null)
      ]);
      data.healthData = healthData;
      renderDetail(panel, data);
--- a/public/observers.js
+++ b/public/observers.js
@@ -38,7 +38,7 @@

  async function loadObservers() {
    try {
-      const data = await api('/observers');
+      const data = await api('/observers', { ttl: 30000 });
      observers = data.observers || [];
      render();
    } catch (e) {
--- a/public/packets.js
+++ b/public/packets.js
@@ -207,7 +207,7 @@

  async function loadObservers() {
    try {
-      const data = await api('/observers');
+      const data = await api('/observers', { ttl: 30000 });
      observers = data.observers || [];
    } catch {}
  }
--- a/server.js
+++ b/server.js
@@ -28,6 +28,30 @@ function computeContentHash(rawHex) {
 const db = require('./db');
 const channelKeys = require("./config.json").channelKeys || {};

+// --- TTL Cache ---
+class TTLCache {
+  constructor() { this.store = new Map(); this.hits = 0; this.misses = 0; }
+  get(key) {
+    const entry = this.store.get(key);
+    if (!entry) { this.misses++; return undefined; }
+    if (Date.now() > entry.expires) { this.store.delete(key); this.misses++; return undefined; }
+    this.hits++;
+    return entry.value;
+  }
+  set(key, value, ttlMs) {
+    this.store.set(key, { value, expires: Date.now() + ttlMs });
+  }
+  invalidate(prefix) {
+    for (const key of this.store.keys()) {
+      if (key.startsWith(prefix)) this.store.delete(key);
+    }
+  }
+  clear() { this.store.clear(); }
+  get size() { return this.store.size; }
+}
+const cache = new TTLCache();
+
+
 // Seed DB if empty
 db.seed();

@@ -94,6 +118,7 @@ app.get('/api/perf', (req, res) => {
    avgMs: perfStats.requests ? Math.round(perfStats.totalMs / perfStats.requests * 10) / 10 : 0,
    endpoints: Object.fromEntries(sorted),
    slowQueries: perfStats.slowQueries.slice(-20),
+    cache: { size: cache.size, hits: cache.hits, misses: cache.misses, hitRate: cache.hits + cache.misses > 0 ? Math.round(cache.hits / (cache.hits + cache.misses) * 1000) / 10 : 0 },
  });
 });

@@ -263,6 +288,15 @@ try {
          db.upsertObserver({ id: observerId, iata: region });
        }

+
+    // Invalidate caches on new data
+    cache.invalidate('analytics:');
+    cache.invalidate('channels');
+    cache.invalidate('node:');
+    cache.invalidate('health:');
+    cache.invalidate('observers');
+    cache.invalidate('bulk-health');
+
        const broadcastData = { id: packetId, raw: msg.raw, decoded, snr: msg.SNR, rssi: msg.RSSI, hash: msg.hash, observer: observerId };
        broadcast({ type: 'packet', data: broadcastData });

@@ -598,6 +632,15 @@ app.post('/api/packets', (req, res) => {
      db.upsertObserver({ id: observer, iata: region || null });
    }

+
+    // Invalidate caches on new data
+    cache.invalidate('analytics:');
+    cache.invalidate('channels');
+    cache.invalidate('node:');
+    cache.invalidate('health:');
+    cache.invalidate('observers');
+    cache.invalidate('bulk-health');
+
    broadcast({ type: 'packet', data: { id: packetId, decoded } });

    res.json({ id: packetId, decoded });
@@ -646,41 +689,85 @@ app.get('/api/nodes/search', (req, res) => {
 // Bulk health summary for analytics — single query approach (MUST be before :pubkey routes)
 app.get('/api/nodes/bulk-health', (req, res) => {
  const limit = Math.min(Number(req.query.limit) || 50, 200);
+  const _ck = 'bulk-health:' + limit;
+  const _c = cache.get(_ck); if (_c) return res.json(_c);
+
  const nodes = db.db.prepare(`SELECT * FROM nodes ORDER BY last_seen DESC LIMIT ?`).all(limit);
  const todayStart = new Date();
  todayStart.setUTCHours(0, 0, 0, 0);
  const todayISO = todayStart.toISOString();

-  const results = nodes.map(node => {
-    const pk = node.public_key;
-    const keyPattern = `%${pk}%`;
-    const namePattern = node.name ? `%${node.name.replace(/[%_]/g, '')}%` : null;
-    const where = namePattern
-      ? `(decoded_json LIKE @k OR decoded_json LIKE @n)`
-      : `decoded_json LIKE @k`;
-    const p = namePattern ? { k: keyPattern, n: namePattern } : { k: keyPattern };
+  if (nodes.length === 0) { cache.set(_ck, [], 60000); return res.json([]); }

-    const observerRows = db.db.prepare(`
-      SELECT observer_id, observer_name, AVG(snr) as avgSnr, AVG(rssi) as avgRssi, COUNT(*) as packetCount
-      FROM packets WHERE ${where} AND observer_id IS NOT NULL GROUP BY observer_id ORDER BY packetCount DESC
-    `).all(p);
-
-    const totalPackets = db.db.prepare(`SELECT COUNT(*) as c FROM packets WHERE ${where}`).get(p).c;
-    const packetsToday = db.db.prepare(`SELECT COUNT(*) as c FROM packets WHERE ${where} AND timestamp > @s`).get({ ...p, s: todayISO }).c;
-    const avgSnr = db.db.prepare(`SELECT AVG(snr) as v FROM packets WHERE ${where}`).get(p).v;
-    const lastHeard = db.db.prepare(`SELECT MAX(timestamp) as v FROM packets WHERE ${where}`).get(p).v;
-
-    return {
-      public_key: pk,
-      name: node.name,
-      role: node.role,
-      lat: node.lat,
-      lon: node.lon,
-      stats: { totalPackets, packetsToday, avgSnr, lastHeard },
-      observers: observerRows
-    };
+  // Build OR conditions for all nodes to fetch matching packets in ONE query
+  const likeConditions = [];
+  const params = {};
+  nodes.forEach((node, i) => {
+    params['k' + i] = '%' + node.public_key + '%';
+    likeConditions.push('decoded_json LIKE @k' + i);
+    if (node.name) {
+      params['n' + i] = '%' + node.name.replace(/[%_]/g, '') + '%';
+      likeConditions.push('decoded_json LIKE @n' + i);
+    }
  });

+  // Single query to get ALL matching packets
+  const allPackets = db.db.prepare(
+    'SELECT decoded_json, snr, rssi, timestamp, observer_id, observer_name FROM packets WHERE ' + likeConditions.join(' OR ')
+  ).all(params);
+
+  // Match packets to nodes in JS
+  const nodeMap = new Map();
+  for (const node of nodes) {
+    nodeMap.set(node.public_key, {
+      node, totalPackets: 0, packetsToday: 0, snrSum: 0, snrCount: 0, lastHeard: null,
+      observers: {}
+    });
+  }
+
+  for (const pkt of allPackets) {
+    const dj = pkt.decoded_json || '';
+    for (const [pk, data] of nodeMap) {
+      const nd = data.node;
+      if (!dj.includes(pk) && !(nd.name && dj.includes(nd.name))) continue;
+      data.totalPackets++;
+      if (pkt.timestamp > todayISO) data.packetsToday++;
+      if (pkt.snr != null) { data.snrSum += pkt.snr; data.snrCount++; }
+      if (!data.lastHeard || pkt.timestamp > data.lastHeard) data.lastHeard = pkt.timestamp;
+      if (pkt.observer_id) {
+        if (!data.observers[pkt.observer_id]) {
+          data.observers[pkt.observer_id] = { name: pkt.observer_name, snrSum: 0, snrCount: 0, rssiSum: 0, rssiCount: 0, count: 0 };
+        }
+        const obs = data.observers[pkt.observer_id];
+        obs.count++;
+        if (pkt.snr != null) { obs.snrSum += pkt.snr; obs.snrCount++; }
+        if (pkt.rssi != null) { obs.rssiSum += pkt.rssi; obs.rssiCount++; }
+      }
+    }
+  }
+
+  const results = [];
+  for (const [pk, data] of nodeMap) {
+    const observerRows = Object.entries(data.observers)
+      .map(([id, o]) => ({
+        observer_id: id, observer_name: o.name,
+        avgSnr: o.snrCount ? o.snrSum / o.snrCount : null,
+        avgRssi: o.rssiCount ? o.rssiSum / o.rssiCount : null,
+        packetCount: o.count
+      }))
+      .sort((a, b) => b.packetCount - a.packetCount);
+    results.push({
+      public_key: pk, name: data.node.name, role: data.node.role,
+      lat: data.node.lat, lon: data.node.lon,
+      stats: {
+        totalPackets: data.totalPackets, packetsToday: data.packetsToday,
+        avgSnr: data.snrCount ? data.snrSum / data.snrCount : null, lastHeard: data.lastHeard
+      },
+      observers: observerRows
+    });
+  }
+
+  cache.set(_ck, results, 60000);
  res.json(results);
 });

@@ -705,16 +792,21 @@ app.get('/api/nodes/network-status', (req, res) => {
 });

 app.get('/api/nodes/:pubkey', (req, res) => {
+  const _ck = 'node:' + req.params.pubkey;
+  const _c = cache.get(_ck); if (_c) return res.json(_c);
  const node = db.getNode(req.params.pubkey);
  if (!node) return res.status(404).json({ error: 'Not found' });
  const recentAdverts = node.recentPackets || [];
  delete node.recentPackets;
-  res.json({ node, recentAdverts });
+  const _nResult = { node, recentAdverts };
+  cache.set(_ck, _nResult, 30000);
+  res.json(_nResult);
 });

 // --- Analytics API ---
 // --- RF Analytics ---
 app.get('/api/analytics/rf', (req, res) => {
+  const _c = cache.get('analytics:rf'); if (_c) return res.json(_c);
  const PTYPES = { 0:'REQ',1:'RESPONSE',2:'TXT_MSG',3:'ACK',4:'ADVERT',5:'GRP_TXT',7:'ANON_REQ',8:'PATH',9:'TRACE',11:'CONTROL' };
  const packets = db.db.prepare(`SELECT snr, rssi, payload_type, timestamp, raw_hex FROM packets WHERE snr IS NOT NULL`).all();

@@ -775,7 +867,7 @@ app.get('/api/analytics/rf', (req, res) => {
  const times = packets.map(p => new Date(p.timestamp).getTime());
  const timeSpanHours = times.length ? (Math.max(...times) - Math.min(...times)) / 3600000 : 0;

-  res.json({
+  const _rfResult = {
    totalPackets: packets.length,
    snr: { min: Math.min(...snrVals), max: Math.max(...snrVals), avg: snrAvg, median: median(snrVals), stddev: stddev(snrVals, snrAvg) },
    rssi: { min: Math.min(...rssiVals), max: Math.max(...rssiVals), avg: rssiAvg, median: median(rssiVals), stddev: stddev(rssiVals, rssiAvg) },
@@ -784,11 +876,14 @@ app.get('/api/analytics/rf', (req, res) => {
    maxPacketSize: packetSizes.length ? Math.max(...packetSizes) : 0,
    avgPacketSize: packetSizes.length ? Math.round(packetSizes.reduce((a, b) => a + b, 0) / packetSizes.length) : 0,
    packetsPerHour, payloadTypes, snrByType: snrByTypeArr, signalOverTime, scatterData, timeSpanHours
-  });
+  };
+  cache.set('analytics:rf', _rfResult, 60000);
+  res.json(_rfResult);
 });

 // --- Topology Analytics ---
 app.get('/api/analytics/topology', (req, res) => {
+  const _c = cache.get('analytics:topology'); if (_c) return res.json(_c);
  const packets = db.db.prepare(`SELECT path_json, snr, decoded_json, observer_id FROM packets WHERE path_json IS NOT NULL AND path_json != '[]'`).all();
  const allNodes = db.db.prepare('SELECT public_key, name, lat, lon FROM nodes WHERE name IS NOT NULL').all();
  const resolveHop = (hop, contextPositions) => {
@@ -939,7 +1034,7 @@ app.get('/api/analytics/topology', (req, res) => {
    .sort((a, b) => a.minDist - b.minDist)
    .slice(0, 50);

-  res.json({
+  const _topoResult = {
    uniqueNodes: new Set(Object.keys(hopFreq)).size,
    avgHops, medianHops, maxHops,
    hopDistribution, topRepeaters, topPairs, hopsVsSnr,
@@ -947,11 +1042,14 @@ app.get('/api/analytics/topology', (req, res) => {
    perObserverReach,
    multiObsNodes,
    bestPathList
-  });
+  };
+  cache.set('analytics:topology', _topoResult, 60000);
+  res.json(_topoResult);
 });

 // --- Channel Analytics ---
 app.get('/api/analytics/channels', (req, res) => {
+  const _c = cache.get('analytics:channels'); if (_c) return res.json(_c);
  const packets = db.db.prepare(`SELECT decoded_json, timestamp FROM packets WHERE payload_type = 5 AND decoded_json IS NOT NULL`).all();

  const channels = {};
@@ -1000,17 +1098,20 @@ app.get('/api/analytics/channels', (req, res) => {
    })
    .sort((a, b) => a.hour.localeCompare(b.hour));

-  res.json({
+  const _chanResult = {
    activeChannels: channelList.length,
    decryptable: channelList.filter(c => !c.encrypted).length,
    channels: channelList,
    topSenders,
    channelTimeline,
    msgLengths
-  });
+  };
+  cache.set('analytics:channels', _chanResult, 60000);
+  res.json(_chanResult);
 });

 app.get('/api/analytics/hash-sizes', (req, res) => {
+  const _c = cache.get('analytics:hash-sizes'); if (_c) return res.json(_c);
  // Get all packets with raw_hex and non-empty paths, extract hash_size from path_length byte
  const packets = db.db.prepare(`
    SELECT raw_hex, path_json, timestamp, payload_type, decoded_json
@@ -1090,13 +1191,15 @@ app.get('/api/analytics/hash-sizes', (req, res) => {
    .sort(([, a], [, b]) => b.packets - a.packets)
    .map(([name, data]) => ({ name, ...data }));

-  res.json({
+  const _hsResult = {
    total: packets.length,
    distribution,
    hourly,
    topHops,
    multiByteNodes
-  });
+  };
+  cache.set('analytics:hash-sizes', _hsResult, 60000);
+  res.json(_hsResult);
 });

 // Resolve path hop hex prefixes to node names
@@ -1246,6 +1349,7 @@ const channelHashNames = {};
 }

 app.get('/api/channels', (req, res) => {
+  const _c = cache.get('channels'); if (_c) return res.json(_c);
  const packets = db.db.prepare(`SELECT * FROM packets WHERE payload_type = 5 ORDER BY timestamp DESC`).all();
  const channelMap = {};

@@ -1304,10 +1408,14 @@ app.get('/api/channels', (req, res) => {
    // Don't double-count if already counted above
  }

-  res.json({ channels: Object.values(channelMap) });
+  const _chResult = { channels: Object.values(channelMap) };
+  cache.set('channels', _chResult, 30000);
+  res.json(_chResult);
 });

 app.get('/api/channels/:hash/messages', (req, res) => {
+  const _ck = 'channels:' + req.params.hash + ':' + (req.query.limit||100) + ':' + (req.query.offset||0);
+  const _c = cache.get(_ck); if (_c) return res.json(_c);
  const { limit = 100, offset = 0 } = req.query;
  const channelHash = req.params.hash;
  const packets = db.db.prepare(`SELECT * FROM packets WHERE payload_type = 5 ORDER BY timestamp ASC`).all();
@@ -1367,17 +1475,22 @@ app.get('/api/channels/:hash/messages', (req, res) => {
  const start = Math.max(0, total - Number(limit) - Number(offset));
  const end = total - Number(offset);
  const messages = allMessages.slice(Math.max(0, start), Math.max(0, end));
-  res.json({ messages, total });
+  const _msgResult = { messages, total };
+  cache.set(_ck, _msgResult, 15000);
+  res.json(_msgResult);
 });

 app.get('/api/observers', (req, res) => {
+  const _c = cache.get('observers'); if (_c) return res.json(_c);
  const observers = db.getObservers();
  const oneHourAgo = new Date(Date.now() - 3600000).toISOString();
  const result = observers.map(o => {
    const lastHour = db.db.prepare(`SELECT COUNT(*) as count FROM packets WHERE observer_id = ? AND timestamp > ?`).get(o.id, oneHourAgo);
    return { ...o, packetsLastHour: lastHour.count };
  });
-  res.json({ observers: result, server_time: new Date().toISOString() });
+  const _oResult = { observers: result, server_time: new Date().toISOString() };
+  cache.set('observers', _oResult, 30000);
+  res.json(_oResult);
 });

 app.get('/api/traces/:hash', (req, res) => {
@@ -1387,8 +1500,11 @@ app.get('/api/traces/:hash', (req, res) => {
 });

 app.get('/api/nodes/:pubkey/health', (req, res) => {
+  const _ck = 'health:' + req.params.pubkey;
+  const _c = cache.get(_ck); if (_c) return res.json(_c);
  const health = db.getNodeHealth(req.params.pubkey);
  if (!health) return res.status(404).json({ error: 'Not found' });
+  cache.set(_ck, health, 30000);
  res.json(health);
 });

@@ -1401,6 +1517,8 @@ app.get('/api/nodes/:pubkey/analytics', (req, res) => {

 // Subpath frequency analysis
 app.get('/api/analytics/subpaths', (req, res) => {
+  const _ck = 'analytics:subpaths:' + (req.query.minLen||2) + ':' + (req.query.maxLen||8) + ':' + (req.query.limit||100);
+  const _c = cache.get(_ck); if (_c) return res.json(_c);
  const minLen = Math.max(2, Number(req.query.minLen) || 2);
  const maxLen = Number(req.query.maxLen) || 8;
  const packets = db.db.prepare(`SELECT path_json FROM packets WHERE path_json IS NOT NULL AND path_json != '[]'`).all();
@@ -1452,7 +1570,9 @@ app.get('/api/analytics/subpaths', (req, res) => {
    .sort((a, b) => b.count - a.count)
    .slice(0, limit);

-  res.json({ subpaths: ranked, totalPaths });
+  const _spResult = { subpaths: ranked, totalPaths };
+  cache.set(_ck, _spResult, 60000);
+  res.json(_spResult);
 });

 // Subpath detail — stats for a specific subpath (by raw hop prefixes)