Receive: fix stats (thanos-io#7373)

If we account stats for remote write and local writes we will count them
twice since the remote write will be counted locally again by the remote
receiver instance.

Signed-off-by: Michael Hoffmann <mhoffm@posteo.de>

pkg/receive/handler.go

@@ -681,35 +681,32 @@ type remoteWriteParams struct {
 	alreadyReplicated bool
 }
 
-func (h *Handler) gatherWriteStats(writes ...map[endpointReplica]map[string]trackedSeries) tenantRequestStats {
+func (h *Handler) gatherWriteStats(localWrites map[endpointReplica]map[string]trackedSeries) tenantRequestStats {
 	var stats tenantRequestStats = make(tenantRequestStats)
 
-	for _, write := range writes {
-		for er := range write {
-			for tenant, series := range write[er] {
-				samples := 0
+	for er := range localWrites {
+		for tenant, series := range localWrites[er] {
+			samples := 0
 
-				for _, ts := range series.timeSeries {
-					samples += len(ts.Samples)
-				}
+			for _, ts := range series.timeSeries {
+				samples += len(ts.Samples)
+			}
 
-				if st, ok := stats[tenant]; ok {
-					st.timeseries += len(series.timeSeries)
-					st.totalSamples += samples
+			if st, ok := stats[tenant]; ok {
+				st.timeseries += len(series.timeSeries)
+				st.totalSamples += samples
 
-					stats[tenant] = st
-				} else {
-					stats[tenant] = requestStats{
-						timeseries:   len(series.timeSeries),
-						totalSamples: samples,
-					}
+				stats[tenant] = st
+			} else {
+				stats[tenant] = requestStats{
+					timeseries:   len(series.timeSeries),
+					totalSamples: samples,
 				}
 			}
 		}
 	}
 
 	return stats
-
 }
 
 func (h *Handler) fanoutForward(ctx context.Context, params remoteWriteParams) (tenantRequestStats, error) {
@@ -739,7 +736,7 @@ func (h *Handler) fanoutForward(ctx context.Context, params remoteWriteParams) (
 		return stats, err
 	}
 
-	stats = h.gatherWriteStats(localWrites, remoteWrites)
+	stats = h.gatherWriteStats(localWrites)
 
 	// Prepare a buffered channel to receive the responses from the local and remote writes. Remote writes will all go
 	// asynchronously and with this capacity we will never block on writing to the channel.