Extract appending from goroutine.

storage/metric/leveldb.go

@@ -540,7 +540,6 @@ func (l *LevelDBMetricPersistence) AppendSamples(samples model.Samples) (err err
 	var (
 		fingerprintToSamples = groupByFingerprint(samples)
 		indexErrChan         = make(chan error)
-		doneCommitting       sync.WaitGroup
 	)
 
 	go func(groups map[model.Fingerprint]model.Samples) {
@@ -555,55 +554,50 @@ func (l *LevelDBMetricPersistence) AppendSamples(samples model.Samples) (err err
 		indexErrChan <- l.indexMetrics(metrics)
 	}(fingerprintToSamples)
 
-	go func() {
-		doneCommitting.Add(1)
-		samplesBatch := leveldb.NewBatch()
-		defer samplesBatch.Close()
-		defer doneCommitting.Done()
-
-		for fingerprint, group := range fingerprintToSamples {
-			for {
-				lengthOfGroup := len(group)
+	samplesBatch := leveldb.NewBatch()
+	defer samplesBatch.Close()
 
-				if lengthOfGroup == 0 {
-					break
-				}
+	for fingerprint, group := range fingerprintToSamples {
+		for {
+			lengthOfGroup := len(group)
 
-				take := *leveldbChunkSize
-				if lengthOfGroup < take {
-					take = lengthOfGroup
-				}
+			if lengthOfGroup == 0 {
+				break
+			}
 
-				chunk := group[0:take]
-				group = group[take:lengthOfGroup]
+			take := *leveldbChunkSize
+			if lengthOfGroup < take {
+				take = lengthOfGroup
+			}
 
-				key := &dto.SampleKey{
-					Fingerprint:   fingerprint.ToDTO(),
-					Timestamp:     indexable.EncodeTime(chunk[0].Timestamp),
-					LastTimestamp: proto.Int64(chunk[take-1].Timestamp.Unix()),
-					SampleCount:   proto.Uint32(uint32(take)),
-				}
+			chunk := group[0:take]
+			group = group[take:lengthOfGroup]
 
-				value := &dto.SampleValueSeries{}
-				for _, sample := range chunk {
-					value.Value = append(value.Value, &dto.SampleValueSeries_Value{
-						Timestamp: proto.Int64(sample.Timestamp.Unix()),
-						Value:     proto.Float32(float32(sample.Value)),
-					})
-				}
+			key := &dto.SampleKey{
+				Fingerprint:   fingerprint.ToDTO(),
+				Timestamp:     indexable.EncodeTime(chunk[0].Timestamp),
+				LastTimestamp: proto.Int64(chunk[take-1].Timestamp.Unix()),
+				SampleCount:   proto.Uint32(uint32(take)),
+			}
 
-				samplesBatch.Put(coding.NewProtocolBufferEncoder(key), coding.NewProtocolBufferEncoder(value))
+			value := &dto.SampleValueSeries{}
+			for _, sample := range chunk {
+				value.Value = append(value.Value, &dto.SampleValueSeries_Value{
+					Timestamp: proto.Int64(sample.Timestamp.Unix()),
+					Value:     proto.Float32(float32(sample.Value)),
+				})
 			}
+
+			samplesBatch.Put(coding.NewProtocolBufferEncoder(key), coding.NewProtocolBufferEncoder(value))
 		}
+	}
 
-		err = l.metricSamples.Commit(samplesBatch)
+	err = l.metricSamples.Commit(samplesBatch)
 
-		if err != nil {
-			panic(err)
-		}
-	}()
+	if err != nil {
+		panic(err)
+	}
 
-	doneCommitting.Wait()
 	err = <-indexErrChan
 	if err != nil {
 		panic(err)