fix(admin): sliding-window rate — no sawtooth drop at bucket boundaries

Replace fixed-window accDelta (resets to 0 every 5 s) with a sliding
window: recentPolls[] holds {t, delta} entries; liveRpm() sums all
entries within the last 5 s and extrapolates to rpm. Old entries age
out naturally so the rate decays smoothly with no hard reset jump.
Chart and label now update continuously without the 0-drop artifact.

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

apix-admin/src/main/resources/META-INF/resources/admin.js

@@ -147,11 +147,9 @@
 
   var buf          = new Array(BUCKETS).fill(0);
   var lastTotal    = null;
-  var accDelta     = 0;          // accumulated since last chart flush
-  var lastActivity = Date.now(); // time of last non-zero delta
+  var lastActivity = Date.now();
   var currentInterval = FAST_INTERVAL;
-  var lastFlushTime = Date.now();
-  var lastWindowRpm = 0;         // rate from previous flush window
+  var recentPolls  = []; // {t, delta} — sliding window entries
 
   var ML = 36, MB = 18;
   var W  = el.parentElement.clientWidth || 900;
@@ -206,25 +204,25 @@
     if (elLive) elLive.textContent = fmt(rpm) + ' req/min (' + pct + '%)';
   }
 
-  // Compute the current in-progress bucket value (capped at rateLimit)
+  // Sliding-window rate: sum of deltas in the last CHART_TICK ms, extrapolated to rpm.
+  // No hard reset at bucket boundaries — rate transitions are smooth.
   function liveRpm() {
-    var windowMs = Math.max(Date.now() - lastFlushTime, 1);
-    return Math.min(Math.round(accDelta * (60000 / windowMs)), rateLimit);
+    var now    = Date.now();
+    var cutoff = now - CHART_TICK;
+    while (recentPolls.length && recentPolls[0].t < cutoff) recentPolls.shift();
+    var sum = recentPolls.reduce(function (s, e) { return s + e.delta; }, 0);
+    return Math.min(Math.round(sum * (60000 / CHART_TICK)), rateLimit);
   }
 
-  // Redraw: historical buf + current live bucket at the right edge ("now")
+  // Redraw: historical buf + live bucket at the right edge
   function redraw() {
     var view = buf.slice(1).concat([liveRpm()]);
     path.attr('d', areaFn(view));
   }
 
-  // Every 5 s: commit the current bucket into buf, reset accumulator
+  // Every 5 s: snapshot the current sliding-window rate into the history buffer
   setInterval(function () {
-    var rpm = liveRpm();
-    lastWindowRpm = rpm;
-    lastFlushTime = Date.now();
-    buf.push(rpm); buf.shift();
-    accDelta = 0;
+    buf.push(liveRpm()); buf.shift();
   }, CHART_TICK);
 
   async function poll() {
@@ -235,12 +233,13 @@
       var total = Number(d.totalRequests) || 0;
       if (lastTotal !== null) {
         var delta = Math.max(0, total - lastTotal);
-        accDelta += delta;
-        if (delta > 0) lastActivity = Date.now();
-        var windowMs = Date.now() - lastFlushTime;
-        var rpm = windowMs > 200 ? liveRpm() : lastWindowRpm;
+        if (delta > 0) {
+          recentPolls.push({t: Date.now(), delta: delta});
+          lastActivity = Date.now();
+        }
+        var rpm = liveRpm();
         updateLabel(rpm);
-        redraw(); // update chart on every poll, not just every 5 s
+        redraw();
       }
       lastTotal = total;
       currentInterval = (Date.now() - lastActivity > IDLE_AFTER_MS) ? IDLE_INTERVAL : FAST_INTERVAL;

apix-admin/src/main/resources/templates/DashboardResource/global.html

@@ -106,6 +106,6 @@ nav {
 <script>var __D = {statsJson.raw};</script>
 <script src="https://cdn.jsdelivr.net/npm/d3@7/dist/d3.min.js"></script>
 <script src="https://cdn.jsdelivr.net/npm/topojson-client@3/dist/topojson-client.min.js"></script>
-<script src="/admin.js?v=9"></script>
+<script src="/admin.js?v=10"></script>
 </body>
 </html>

apix-admin/src/main/resources/templates/DashboardResource/sandbox.html

@@ -151,6 +151,6 @@ button.promote:hover { background: #2ea043; }
 <script>var __D = {dataJson.raw};</script>
 <script src="https://cdn.jsdelivr.net/npm/d3@7/dist/d3.min.js"></script>
 <script src="https://cdn.jsdelivr.net/npm/topojson-client@3/dist/topojson-client.min.js"></script>
-<script src="/admin.js?v=9"></script>
+<script src="/admin.js?v=10"></script>
 </body>
 </html>