Fixed native histogram proto conversion in remote engine

Signed-off-by: Sebastian Rabenhorst <[email protected]>

pkg/query/remote_engine.go

@@ -11,6 +11,7 @@ import (
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
 	"github.com/pkg/errors"
+	"github.com/prometheus/prometheus/model/histogram"
 	"github.com/prometheus/prometheus/model/labels"
 	"github.com/prometheus/prometheus/promql"
 	"github.com/prometheus/prometheus/promql/parser"
@@ -197,10 +198,18 @@ func (r *remoteQuery) Exec(ctx context.Context) *promql.Result {
 				F: s.Value,
 			})
 		}
-		for _, h := range ts.Histograms {
+		for _, hp := range ts.Histograms {
+			var fh *histogram.FloatHistogram
+
+			if hp.IsFloatHistogram() {
+				fh = prompb.FloatHistogramProtoToFloatHistogram(hp)
+			} else {
+				fh = prompb.HistogramProtoToFloatHistogram(hp)
+			}
+
 			series.Histograms = append(series.Histograms, promql.HPoint{
-				T: h.Timestamp,
-				H: prompb.HistogramProtoToFloatHistogram(h),
+				T: hp.Timestamp,
+				H: fh,
 			})
 		}
 		result = append(result, series)