Improving spinlocks in CollectAgent SensorCache

collectagent/collectagent.cpp

@@ -152,6 +152,7 @@ bool sensorGroupQueryCallback(const std::vector<string>& names, const uint64_t s
         // Creating a SID to perform the query
         if (sid.mqttTopicConvert(topic)) {
             try {
+                mySensorCache.wait();
                 if (sensorMap.count(sid) > 0 && sensorMap[sid].getView(startTs, endTs, buffer, rel)) {
                     // Data was found, can continue to next SID
                     successCtr++;

collectagent/sensorcache.h

@@ -105,6 +105,14 @@ public:
 	**/
 	uint64_t clean(uint64_t t);
 
+	/**
+	* @brief               Waits for internal updates to finish.
+	*/
+	const void wait() {
+		while(_updating.load()) {}
+		return;
+	}
+
     /**
     * @brief  Set a new maximum cache length.
     *