Updated subsampling function

- If a subSampling value of 0 or lower is chosen for a sensor, it will
never be pushed out over MQTT/Cassandra and only kept in memory

analytics/includes/OperatorConfiguratorTemplate.h

@@ -476,7 +476,7 @@ protected:
             } else if (boost::iequals(val.first, "delta")) {
                 sBase.setDelta(to_bool(val.second.data()));
             } else if (boost::iequals(val.first, "subSampling")) {
-                sBase.setSubsampling(std::stoul(val.second.data()));
+                sBase.setSubsampling(std::stoi(val.second.data()));
             }
         }
         sensorBase(sBase, config);

common/include/sensorbase.h

@@ -118,7 +118,7 @@ public:
 	const std::string&		getMqtt() 			const	{ return _mqtt; }
 	bool					getSkipConstVal()	const	{ return _skipConstVal; }
 	unsigned				getCacheInterval()	const	{ return _cacheInterval; }
-	unsigned 				getSubsampling()	const   { return _subsamplingFactor; }
+	int 					getSubsampling()	const   { return _subsamplingFactor; }
 	const CacheEntry* const	getCache() 			const	{ return _cache.get(); }
 	const reading_t&		getLatestValue()	const	{ return _latestValue; }
 	const bool				isInit()			const 	{ return _cache && _readingQueue; }
@@ -131,7 +131,7 @@ public:
 	void	setName(const std::string& name)				{ _name = name; }
 	void	setMqtt(const std::string& mqtt)				{ _mqtt = mqtt; }
 	void 	setCacheInterval(unsigned cacheInterval)		{ _cacheInterval = cacheInterval; }
-	void	setSubsampling(unsigned factor)					{ _subsamplingFactor = factor; }
+	void	setSubsampling(int factor)						{ _subsamplingFactor = factor; }
 	void    setLastRaw(int64_t raw)                         { _lastRawValue.value = raw; }
 	void    setLastURaw(uint64_t raw)                       { _lastRawUValue.value = raw; }
 
@@ -253,7 +253,7 @@ public:
         else
             _accumulator.value = reading.value;
 
-        if (_subsamplingIndex++ % _subsamplingFactor == 0) {
+        if (_subsamplingFactor>0 && _subsamplingIndex++%_subsamplingFactor==0) {
             _accumulator.timestamp = reading.timestamp;
             //TODO: if sensor starts with values of 0, these won't be pushed. This should be fixed
             if( !(_skipConstVal && (_accumulator.value == _lastSentValue.value)) ) {
@@ -280,7 +280,7 @@ protected:
 	std::string _mqtt;
 	bool _skipConstVal;
 	unsigned int _cacheInterval;
-	unsigned int _subsamplingFactor;
+	int _subsamplingFactor;
 	unsigned int _subsamplingIndex;
 	std::unique_ptr<CacheEntry> _cache;
 	bool _delta;

dcdbpusher/README.md

@@ -302,7 +302,7 @@ All the different plugins share some same general principles in common regarding
     3. Sensors hold only those attributes which are necessary to uniquely identify the target sensor. Common base attributes:
         * __mqttsuffix__  (to make its [mqtt-topic](#mqttTopic) unique)
         * __delta__ (identifies a monotonic sensor. If set to "on", differences between successive readings are collected)
-        * __subSampling__ (subsampling factor S. If > 1, only one reading every S is sent over MQTT, and the others are kept locally)
+        * __subSampling__ (subsampling factor S. If S>=1, only one reading every S is sent over MQTT, and the others are kept locally. If S<1, readings are never sent out and only kept locally)
 5. Be aware that naming of sensor/group/entity is not fixed. A plugin developer can name them as he likes, e.g. counter/multicounter/host.
 6. It is possible to define template groups or entities in the config file, but not template sensors (as a sensor should only consists of attributs which make him unique this would not be too useful). To specify a template group/entity simply prefix its definition with `template_` (see the example below). You can reference them later by using the `default` attribute. A template entity can consist of groups and these in turn can consist of sensors. When using a template, all of its attribute values are copied to the actual sensor. Copied attributes can be overwritten in the actual entity/sensor (some of them even should be overwritten, e.g. the mqttPart). However, groups/sensors associated with a template are copied to the actual entity/group and can NOT be overwritten. One can specify further groups/sensors which are then added to those copied from the template. Template entitys/groups itself or sensors within them are never used in live operation of the plugin. They are purely cosmetic for convenient configuration.
  

dcdbpusher/includes/ConfiguratorTemplate.h

@@ -382,7 +382,7 @@ protected:
 			} else if (boost::iequals(val.first, "delta")) {
 				sBase.setDelta(to_bool(val.second.data()));
 			} else if (boost::iequals(val.first, "subSampling")) {
-				sBase.setSubsampling(std::stoul(val.second.data()));
+				sBase.setSubsampling(std::stoi(val.second.data()));
 			}
 		}
 		sensorBase(sBase, config);
@@ -955,7 +955,7 @@ protected:
             } else if (boost::iequals(val.first, "delta")) {
                 sBase.setDelta(to_bool(val.second.data()));
             } else if (boost::iequals(val.first, "subSampling")) {
-                sBase.setSubsampling(std::stoul(val.second.data()));
+                sBase.setSubsampling(std::stoi(val.second.data()));
             }
         }
         sensorBase(sBase, config);