From f98c663406ca266a4e34da40f9e465e1c2aa1eb7 Mon Sep 17 00:00:00 2001
From: Adam Gessaman <adam@gessaman.com>
Date: Mon, 9 Feb 2026 09:48:34 -0800
Subject: [PATCH] Refine memory pressure management in MQTTBridge

- Updated pressure window and threshold constants to differentiate between critical and moderate memory pressure scenarios.
- Enhanced recovery logic to trigger based on specific pressure conditions, improving responsiveness to memory fragmentation.
- Added explicit calls to recreate analyzer client objects during recovery, ensuring proper setup after memory management actions.

These changes aim to optimize memory handling and recovery processes in the MQTTBridge, enhancing overall stability.
---
 src/helpers/bridges/MQTTBridge.cpp | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/helpers/bridges/MQTTBridge.cpp b/src/helpers/bridges/MQTTBridge.cpp
index 6e6817fb..4b778895 100644
--- a/src/helpers/bridges/MQTTBridge.cpp
+++ b/src/helpers/bridges/MQTTBridge.cpp
@@ -1134,10 +1134,12 @@ void MQTTBridge::ensureMainMqttClient() {
 #ifdef ESP_PLATFORM
 void MQTTBridge::runCriticalMemoryCheckAndRecovery() {
   const unsigned long CRITICAL_CHECK_INTERVAL_MS = 60000;   // Sample heap at most every 60s
-  const unsigned long PRESSURE_WINDOW_MS = 180000;           // Recover if under pressure for 3 min
+  const unsigned long PRESSURE_WINDOW_CRITICAL_MS = 180000;  // Recover if critical pressure for 3 min
+  const unsigned long PRESSURE_WINDOW_MODERATE_MS = 300000; // Recover if moderate pressure for 5 min
   const unsigned long RECOVERY_THROTTLE_MS = 300000;         // 5 min between recovery runs
   const unsigned long CRITICAL_LOG_INTERVAL_MS = 900000;     // Log CRITICAL/WARNING/client count at most every 15 min
-  const size_t PRESSURE_THRESHOLD = 58000;                   // max_alloc below this = under pressure
+  const size_t PRESSURE_THRESHOLD_CRITICAL = 58000;           // max_alloc below this = critical (3 min window)
+  const size_t PRESSURE_THRESHOLD_MODERATE = 70000;          // max_alloc below this = under pressure (clear when >= this)
 
   unsigned long now = millis();
   if (now - _last_critical_check_run < CRITICAL_CHECK_INTERVAL_MS) {
@@ -1156,8 +1158,8 @@ void MQTTBridge::runCriticalMemoryCheckAndRecovery() {
   agentLogHeap("MQTTBridge.cpp:runCriticalMemoryCheckAndRecovery", "critical_memory_check", "H1_H4", free_h, max_alloc, internal_f, spiram_f);
   #endif
 
-  // Pressure timer: track how long max_alloc has been below threshold
-  if (max_alloc >= PRESSURE_THRESHOLD) {
+  // Pressure timer: track how long max_alloc has been below moderate threshold
+  if (max_alloc >= PRESSURE_THRESHOLD_MODERATE) {
     _fragmentation_pressure_since = 0;
   } else {
     if (_fragmentation_pressure_since == 0) {
@@ -1180,13 +1182,16 @@ void MQTTBridge::runCriticalMemoryCheckAndRecovery() {
     MQTT_DEBUG_PRINTLN("MQTT clients active: %d (main=%d us=%d eu=%d)", n_main + n_us + n_eu, n_main, n_us, n_eu);
   }
 
-  // Dedicated recovery timer: recover if under pressure for PRESSURE_WINDOW_MS and throttle passed
+  // Dedicated recovery: critical (<58k) recovers after 3 min; moderate (58k–70k) after 5 min
+  unsigned long required_window_ms = (max_alloc < PRESSURE_THRESHOLD_CRITICAL)
+      ? PRESSURE_WINDOW_CRITICAL_MS
+      : PRESSURE_WINDOW_MODERATE_MS;
   if (_fragmentation_pressure_since != 0 &&
-      (now - _fragmentation_pressure_since) >= PRESSURE_WINDOW_MS &&
+      (now - _fragmentation_pressure_since) >= required_window_ms &&
       (now - _last_fragmentation_recovery) >= RECOVERY_THROTTLE_MS) {
     _last_fragmentation_recovery = now;
     _fragmentation_pressure_since = 0;
-    MQTT_DEBUG_PRINTLN("Fragmentation recovery: recreating MQTT clients (max_alloc=%d, pressure 3 min)", (int)max_alloc);
+    MQTT_DEBUG_PRINTLN("Fragmentation recovery: recreating MQTT clients (max_alloc=%d, pressure %lu min)", (int)max_alloc, (unsigned long)(required_window_ms / 60000));
     recreateMqttClientsForFragmentationRecovery();
   }
 }
@@ -1227,6 +1232,9 @@ void MQTTBridge::recreateMqttClientsForFragmentationRecovery() {
   _cached_has_brokers = false;
   _cached_has_analyzer_servers = false;
   setupAnalyzerServers();
+  // Recreate analyzer client objects (we just set them to nullptr above; setupAnalyzerServers
+  // only calls setupAnalyzerClients when enabled flags change, so we must call it explicitly).
+  setupAnalyzerClients();
 }
 
 void MQTTBridge::connectToBrokers() {