From 6f359b11d3cace45b3e229afab91074a333bd49d Mon Sep 17 00:00:00 2001
From: acidburns <neon22@web.de>
Date: Wed, 18 Feb 2026 01:26:43 +0100
Subject: [PATCH] sender: drain backlog with ack-gated catch-up sends

---
 src/main.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/main.cpp b/src/main.cpp
index cec2898..30010aa 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1417,6 +1417,12 @@ static void sender_loop() {
         }
       }
     }
+
+    // Catch-up mode: when backlog exists, send next queued batch without waiting
+    // for the regular 30s cadence.
+    if (!g_batch_ack_pending && g_batch_count > 1) {
+      send_meter_batch(last_sample_ts());
+    }
   } else {
     if (!g_batch_ack_pending && now_ms - g_last_sync_request_ms >= SYNC_REQUEST_INTERVAL_MS) {
       g_last_sync_request_ms = now_ms;