Optimize the decoding of SampleStream (#5349)

* Implementing decodeSampleStream

Signed-off-by: Alan Protasio <[email protected]>

* lint

Signed-off-by: Alan Protasio <[email protected]>

* lint

Signed-off-by: Alan Protasio <[email protected]>

---------

Signed-off-by: Alan Protasio <[email protected]>

Author: alanprot

pkg/querier/tripperware/instantquery/instant_query_test.go

@@ -11,11 +11,13 @@ import (
 	"testing"
 	"time"
 
+	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"github.com/weaveworks/common/httpgrpc"
 	"github.com/weaveworks/common/user"
 
+	"github.com/cortexproject/cortex/pkg/cortexpb"
 	"github.com/cortexproject/cortex/pkg/querier/tripperware"
 )
 
@@ -444,3 +446,66 @@ func Test_sortPlanForQuery(t *testing.T) {
 		})
 	}
 }
+
+func Benchmark_Decode(b *testing.B) {
+	maxSamplesCount := 1000000
+	samples := make([]tripperware.SampleStream, maxSamplesCount)
+
+	for i := 0; i < maxSamplesCount; i++ {
+		samples[i].Labels = append(samples[i].Labels, cortexpb.LabelAdapter{Name: fmt.Sprintf("Sample%v", i), Value: fmt.Sprintf("Value%v", i)})
+		samples[i].Labels = append(samples[i].Labels, cortexpb.LabelAdapter{Name: fmt.Sprintf("Sample2%v", i), Value: fmt.Sprintf("Value2%v", i)})
+		samples[i].Labels = append(samples[i].Labels, cortexpb.LabelAdapter{Name: fmt.Sprintf("Sample3%v", i), Value: fmt.Sprintf("Value3%v", i)})
+		samples[i].Samples = append(samples[i].Samples, cortexpb.Sample{TimestampMs: int64(i), Value: float64(i)})
+	}
+
+	for name, tc := range map[string]struct {
+		sampleStream []tripperware.SampleStream
+	}{
+		"100 samples": {
+			sampleStream: samples[:100],
+		},
+		"1000 samples": {
+			sampleStream: samples[:1000],
+		},
+		"10000 samples": {
+			sampleStream: samples[:10000],
+		},
+		"100000 samples": {
+			sampleStream: samples[:100000],
+		},
+		"1000000 samples": {
+			sampleStream: samples[:1000000],
+		},
+	} {
+		b.Run(name, func(b *testing.B) {
+			r := PrometheusInstantQueryResponse{
+				Data: PrometheusInstantQueryData{
+					ResultType: model.ValMatrix.String(),
+					Result: PrometheusInstantQueryResult{
+						Result: &PrometheusInstantQueryResult_Matrix{
+							Matrix: &Matrix{
+								SampleStreams: tc.sampleStream,
+							},
+						},
+					},
+				},
+			}
+
+			body, err := json.Marshal(r)
+			require.NoError(b, err)
+
+			b.ResetTimer()
+			b.ReportAllocs()
+
+			for i := 0; i < b.N; i++ {
+				response := &http.Response{
+					StatusCode: 200,
+					Body:       io.NopCloser(bytes.NewBuffer(body)),
+				}
+				_, err := InstantQueryCodec.DecodeResponse(context.Background(), response, nil)
+				require.NoError(b, err)
+			}
+		})
+	}
+
+}

pkg/querier/tripperware/query.go

@@ -83,6 +83,31 @@ type Request interface {
 	WithStats(stats string) Request
 }
 
+func decodeSampleStream(ptr unsafe.Pointer, iter *jsoniter.Iterator) {
+	lbls := labels.Labels{}
+	samples := []cortexpb.Sample{}
+	for field := iter.ReadObject(); field != ""; field = iter.ReadObject() {
+		switch field {
+		case "metric":
+			iter.ReadVal(&lbls)
+		case "values":
+			for {
+				if !iter.ReadArray() {
+					break
+				}
+				s := cortexpb.Sample{}
+				cortexpb.SampleJsoniterDecode(unsafe.Pointer(&s), iter)
+				samples = append(samples, s)
+			}
+		}
+	}
+
+	*(*SampleStream)(ptr) = SampleStream{
+		Samples: samples,
+		Labels:  cortexpb.FromLabelsToLabelAdapters(lbls),
+	}
+}
+
 func encodeSampleStream(ptr unsafe.Pointer, stream *jsoniter.Stream) {
 	ss := (*SampleStream)(ptr)
 	stream.WriteObjectStart()
@@ -160,6 +185,7 @@ func init() {
 	jsoniter.RegisterTypeEncoderFunc("tripperware.PrometheusResponseQueryableSamplesStatsPerStep", PrometheusResponseQueryableSamplesStatsPerStepJsoniterEncode, func(unsafe.Pointer) bool { return false })
 	jsoniter.RegisterTypeDecoderFunc("tripperware.PrometheusResponseQueryableSamplesStatsPerStep", PrometheusResponseQueryableSamplesStatsPerStepJsoniterDecode)
 	jsoniter.RegisterTypeEncoderFunc("tripperware.SampleStream", encodeSampleStream, func(unsafe.Pointer) bool { return false })
+	jsoniter.RegisterTypeDecoderFunc("tripperware.SampleStream", decodeSampleStream)
 }
 
 func EncodeTime(t int64) string {