metrics: Make LatencySample and Counter inherit from IMetric

fdbrpc/Stats.actor.cpp

@@ -22,8 +22,8 @@
 #include "flow/actorcompiler.h" // has to be last include
 
 Counter::Counter(std::string const& name, CounterCollection& collection)
-  : name(name), interval_start(0), last_event(0), interval_sq_time(0), roughness_interval_start(0), interval_delta(0),
-    interval_start_value(0) {
+  : IMetric(name), interval_start(0), last_event(0), interval_sq_time(0), roughness_interval_start(0),
+    interval_delta(0), interval_start_value(0) {
 	metric.init(collection.getName() + "." + (char)toupper(name.at(0)) + name.substr(1), collection.getId());
 	collection.addCounter(this);
 }
@@ -81,6 +81,8 @@ void Counter::clear() {
 	metric = 0;
 }
 
+void Counter::flush(MetricBatch& batch) {}
+
 void CounterCollection::logToTraceEvent(TraceEvent& te) const {
 	for (ICounter* c : counters) {
 		te.detail(c->getName().c_str(), c);

fdbrpc/include/fdbrpc/Stats.h

@@ -100,7 +100,7 @@ public:
 	    std::function<void(TraceEvent&)> const& decorator = [](auto& te) {});
 };
 
-struct Counter final : ICounter, NonCopyable {
+struct Counter final : ICounter, NonCopyable, IMetric {
 public:
 	typedef int64_t Value;
 
@@ -134,8 +134,9 @@ public:
 	bool hasRate() const override { return true; }
 	bool hasRoughness() const override { return true; }
 
+	void flush(MetricBatch& batch) override;
+
 private:
-	std::string name;
 	double interval_start, last_event, interval_sq_time, roughness_interval_start;
 	Value interval_delta, interval_start_value;
 	Int64MetricHandle metric;
@@ -214,10 +215,10 @@ public:
 	~LatencyBands();
 };
 
-class LatencySample {
+class LatencySample : public IMetric {
 public:
 	LatencySample(std::string name, UID id, double loggingInterval, double accuracy)
-	  : name(name), id(id), sampleStart(now()), sketch(accuracy),
+	  : IMetric(name), id(id), sampleStart(now()), sketch(accuracy),
 	    latencySampleEventHolder(makeReference<EventCacheHolder>(id.toString() + "/" + name)) {
 		assert(accuracy > 0);
 		if (accuracy <= 0) {
@@ -227,9 +228,9 @@ public:
 	}
 
 	void addMeasurement(double measurement) { sketch.addSample(measurement); }
+	void flush(MetricBatch& batch) override {}
 
 private:
-	std::string name;
 	UID id;
 	double sampleStart;
 

flow/TDMetric.cpp

@@ -198,7 +198,7 @@ void DynamicEventMetric::flushData(MetricKeyRef const& mk, uint64_t rollTime, Me
 	for (auto& [name, field] : fields)
 		field->flushField(mk, rollTime, batch);
 	if (!latestRecorded) {
-		batch.updates.emplace_back(mk.packLatestKey(), StringRef());
+		batch.scope.updates.emplace_back(mk.packLatestKey(), StringRef());
 		latestRecorded = true;
 	}
 }

flow/include/flow/TDMetric.actor.h

@@ -168,6 +168,16 @@ struct MetricBatch {
 	FDBScope scope;
 	std::string statsd_message;
 
+	MetricBatch() {}
+
+	MetricBatch(FDBScope* in) {
+		assert(in != nullptr);
+		scope.inserts = std::move(in->inserts);
+		scope.appends = std::move(in->appends);
+		scope.updates = std::move(in->updates);
+		scope.callbacks = std::move(in->callbacks);
+	}
+
 	void clear() {
 		scope.clear();
 		statsd_message.clear();
@@ -618,7 +628,7 @@ public:
 	                                               IMetricDB* db,
 	                                               Standalone<MetricKeyRef> mk,
 	                                               uint64_t rollTime,
-	                                               MetricBatch* batch) {
+	                                               FDBScope* scope) {
 
 		Optional<Standalone<StringRef>> block = wait(db->getLastBlock(mk.packDataKey(-1)));
 
@@ -647,7 +657,8 @@ public:
 
 		// Now flush the level data up to the rollTime argument and patch anything older than
 		// lastTimeRequiringHeaderPatch
-		self->flushUpdates(mk, rollTime, *batch);
+		MetricBatch batch{ scope };
+		self->flushUpdates(mk, rollTime, batch);
 
 		return Void();
 	}
@@ -666,8 +677,8 @@ public:
 		Standalone<MetricKeyRef> mkCopy = mk;
 
 		// Previous header is not present so queue a callback which will update it
-		batch.scope.callbacks.push_back([=](IMetricDB* db, MetricBatch* batch) mutable -> Future<Void> {
-			return updatePreviousHeader(this, db, mkCopy, rollTime, batch);
+		batch.scope.callbacks.push_back([=](IMetricDB* db, FDBScope* s) mutable -> Future<Void> {
+			return updatePreviousHeader(this, db, mkCopy, rollTime, s);
 		});
 	}
 };
@@ -1433,11 +1444,12 @@ template <typename E>
 using EventMetricHandle = MetricHandle<EventMetric<E>>;
 
 class IMetric {
+protected:
 	std::string name;
 
 public:
 	IMetric(const std::string& n) : name{ n } {}
-	virtual ~IMetric() = 0;
+	virtual ~IMetric() {}
 	virtual void flush(MetricBatch&) = 0;
 };