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) {
@@ -555,11 +554,8 @@ 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 {
@@ -601,9 +597,7 @@ func (l *LevelDBMetricPersistence) AppendSamples(samples model.Samples) (err err
 	if err != nil {
 		panic(err)
 	}
-	}()
 
-	doneCommitting.Wait()
 	err = <-indexErrChan
 	if err != nil {
 		panic(err)