Fixing performance issues on QoS 1

- Implemented a check in MQTTPusher that prevents the main publish
loop from being invoked anytime mosquitto_loop returns, but only once
every second at most

src/MQTTPusher.cpp

@@ -63,6 +63,8 @@ MQTTPusher::~MQTTPusher() {
 }
 
 void MQTTPusher::push() {
+    int mosqErr;
+    uint64_t idleTime = 0;
 	//connect to broker (if necessary)
 	while (_keepRunning && !_connected) {
 		if (mosquitto_connect(_mosq, _brokerHost.c_str(), _brokerPort, 1000) != MOSQ_ERR_SUCCESS) {
@@ -100,51 +102,54 @@ void MQTTPusher::push() {
 				LOGM(info) << "Connection established!";
 			}
 		}
-		
+
 		if (_connected) {
-			totalCount = 0;
-			// Push sensor data
-			for(auto& p : _plugins) {
-				if(_doHalt) {
-					//for faster response
-					break;
-				}
-				for(const auto& g : p.configurator->getSensorGroups()) {
-					for(const auto& s : g->getSensors()) {
-						if (s->getSizeOfReadingQueue() >= g->getMinValues()) {
-							if(_overrideMsgCap || totalCount < _maxNumberOfMessages){
-								if (sendReadings(*s, reads, totalCount) > 0) {
-									break;
-								}
-							} else {
-								break; //ultimately we will go to sleep 1 second
-							}
-						}
-					}
-				}
-			}
-			// Push output analytics sensors
-			for(auto& p : _analyticsPlugins) {
-				if(_doHalt) {
-					break;
-				}
-				for(const auto& a : p.configurator->getAnalyzers()) {
-					for(const auto& u : a->getUnits()) {
-						for(const auto& s : u->getBaseOutputs()) {
-							if (s->getSizeOfReadingQueue() >= a->getMinValues()) {
-								if (_overrideMsgCap || totalCount < _maxNumberOfMessages) {
-									if (sendReadings(*s, reads, totalCount) > 0) {
-										break;
-									}
-								} else {
-									break;
-								}
-							}
-						}
-					}
-				}
-			}
-			int mosqErr;
+            if(getTimestamp() - idleTime >= PUSHER_IDLETIME) {
+                idleTime = getTimestamp();
+                totalCount = 0;
+                // Push sensor data
+                for (auto &p : _plugins) {
+                    if (_doHalt) {
+                        //for faster response
+                        break;
+                    }
+                    for (const auto &g : p.configurator->getSensorGroups()) {
+                        for (const auto &s : g->getSensors()) {
+                            if (s->getSizeOfReadingQueue() >= g->getMinValues()) {
+                                if (_overrideMsgCap || totalCount < _maxNumberOfMessages) {
+                                    if (sendReadings(*s, reads, totalCount) > 0) {
+                                        break;
+                                    }
+                                } else {
+                                    break; //ultimately we will go to sleep 1 second
+                                }
+                            }
+                        }
+                    }
+                }
+                // Push output analytics sensors
+                for (auto &p : _analyticsPlugins) {
+                    if (_doHalt) {
+                        break;
+                    }
+                    for (const auto &a : p.configurator->getAnalyzers()) {
+                        for (const auto &u : a->getUnits()) {
+                            for (const auto &s : u->getBaseOutputs()) {
+                                if (s->getSizeOfReadingQueue() >= a->getMinValues()) {
+                                    if (_overrideMsgCap || totalCount < _maxNumberOfMessages) {
+                                        if (sendReadings(*s, reads, totalCount) > 0) {
+                                            break;
+                                        }
+                                    } else {
+                                        break;
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+
 			if ((mosqErr = mosquitto_loop(_mosq, -1, 1)) != MOSQ_ERR_SUCCESS) {
 				if (mosqErr == MOSQ_ERR_CONN_LOST) {
 					LOGM(info) << "Disconnected.";

src/MQTTPusher.h

@@ -9,6 +9,7 @@
 #define MQTTPUSHER_H_
 
 #define DCDB_MAP "/DCDB_MAP/"
+#define PUSHER_IDLETIME 1000000000
 
 #include <mosquitto.h>
 #include "includes/PluginDefinitions.h"