Add Exemplar to metricdata package (#3849)

* Add Exemplar to metricdata pkg * Update histogram Aggregator * Update opencensus bridge * Update prometheus exporter * Update OTLP exporter * Update stdoutmetric exporter * Add changes to changelog * Update fail tests * Add tests for IgnoreExemplars * Fix merge
2025-11-25 22:41:46 +02:00 · 2023-03-14 07:56:18 -07:00
parent b62eb2ca88
commit 01b8f15a72
16 changed files with 550 additions and 143 deletions
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 ### Added

 - The `WithoutTimestamps` option to `go.opentelemetry.io/otel/exporters/stdout/stdoutmetric` to sets all timestamps to zero. (#3828)
+- The new `Exemplar` type is added to `go.opentelemetry.io/otel/sdk/metric/metricdata`.
+  Both the `DataPoint` and `HistogramDataPoint` types from that package have a new field of `Exemplars` containing the sampled exemplars for their timeseries. (#3849)

 ### Changed

@@ -18,6 +20,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Optimize memory allocation when creation new metric instruments in `go.opentelemetry.io/otel/sdk/metric`. (#3832)
 - Avoid creating new objects on all calls to `WithDeferredSetup` and `SkipContextSetup` in OpenTracing bridge. (#3833)
 - The `New` and `Detect` functions from `go.opentelemetry.io/otel/sdk/resource` return errors that wrap underlying errors instead of just containing the underlying error strings. (#3844)
+- Both the `Histogram` and `HistogramDataPoint` are redefined with a generic argument of `[N int64 | float64]` in `go.opentelemetry.io/otel/sdk/metric/metricdata`. (#3849)

 ### Removed

--- a/bridge/opencensus/internal/ocmetric/metric.go
+++ b/bridge/opencensus/internal/ocmetric/metric.go
@@ -127,8 +127,8 @@ func convertNumberDataPoints[N int64 | float64](labelKeys []ocmetricdata.LabelKe

 // convertHistogram converts OpenCensus Distribution timeseries to an
 // OpenTelemetry Histogram aggregation.
-func convertHistogram(labelKeys []ocmetricdata.LabelKey, ts []*ocmetricdata.TimeSeries) (metricdata.Histogram, error) {
-	points := make([]metricdata.HistogramDataPoint, 0, len(ts))
+func convertHistogram(labelKeys []ocmetricdata.LabelKey, ts []*ocmetricdata.TimeSeries) (metricdata.Histogram[float64], error) {
+	points := make([]metricdata.HistogramDataPoint[float64], 0, len(ts))
 	var errInfo []string
 	for _, t := range ts {
 		attrs, err := convertAttrs(labelKeys, t.LabelValues)
@@ -152,7 +152,7 @@ func convertHistogram(labelKeys []ocmetricdata.LabelKey, ts []*ocmetricdata.Time
 				continue
 			}
 			// TODO: handle exemplars
-			points = append(points, metricdata.HistogramDataPoint{
+			points = append(points, metricdata.HistogramDataPoint[float64]{
 				Attributes:   attrs,
 				StartTime:    t.StartTime,
 				Time:         p.Time,
@@ -167,7 +167,7 @@ func convertHistogram(labelKeys []ocmetricdata.LabelKey, ts []*ocmetricdata.Time
 	if len(errInfo) > 0 {
 		aggregatedError = fmt.Errorf("%w: %v", errHistogramDataPoint, errInfo)
 	}
-	return metricdata.Histogram{DataPoints: points, Temporality: metricdata.CumulativeTemporality}, aggregatedError
+	return metricdata.Histogram[float64]{DataPoints: points, Temporality: metricdata.CumulativeTemporality}, aggregatedError
 }

 // convertBucketCounts converts from OpenCensus bucket counts to slice of uint64.
--- a/bridge/opencensus/internal/ocmetric/metric_test.go
+++ b/bridge/opencensus/internal/ocmetric/metric_test.go
@@ -214,8 +214,8 @@ func TestConvertMetrics(t *testing.T) {
 					Name:        "foo.com/histogram-a",
 					Description: "a testing histogram",
 					Unit:        "1",
-					Data: metricdata.Histogram{
-						DataPoints: []metricdata.HistogramDataPoint{
+					Data: metricdata.Histogram[float64]{
+						DataPoints: []metricdata.HistogramDataPoint[float64]{
 							{
 								Attributes: attribute.NewSet(attribute.KeyValue{
 									Key:   attribute.Key("a"),
@@ -387,9 +387,9 @@ func TestConvertMetrics(t *testing.T) {
 					Name:        "foo.com/histogram-a",
 					Description: "a testing histogram",
 					Unit:        "1",
-					Data: metricdata.Histogram{
+					Data: metricdata.Histogram[float64]{
 						Temporality: metricdata.CumulativeTemporality,
-						DataPoints:  []metricdata.HistogramDataPoint{},
+						DataPoints:  []metricdata.HistogramDataPoint[float64]{},
 					},
 				},
 			},
--- a/exporters/otlp/otlpmetric/internal/transform/metricdata.go
+++ b/exporters/otlp/otlpmetric/internal/transform/metricdata.go
@@ -95,7 +95,9 @@ func metric(m metricdata.Metrics) (*mpb.Metric, error) {
 		out.Data, err = Sum[int64](a)
 	case metricdata.Sum[float64]:
 		out.Data, err = Sum[float64](a)
-	case metricdata.Histogram:
+	case metricdata.Histogram[int64]:
+		out.Data, err = Histogram(a)
+	case metricdata.Histogram[float64]:
 		out.Data, err = Histogram(a)
 	default:
 		return out, fmt.Errorf("%w: %T", errUnknownAggregation, a)
@@ -155,7 +157,7 @@ func DataPoints[N int64 | float64](dPts []metricdata.DataPoint[N]) []*mpb.Number
 // Histogram returns an OTLP Metric_Histogram generated from h. An error is
 // returned with a partial Metric_Histogram if the temporality of h is
 // unknown.
-func Histogram(h metricdata.Histogram) (*mpb.Metric_Histogram, error) {
+func Histogram[N int64 | float64](h metricdata.Histogram[N]) (*mpb.Metric_Histogram, error) {
 	t, err := Temporality(h.Temporality)
 	if err != nil {
 		return nil, err
@@ -170,7 +172,7 @@ func Histogram(h metricdata.Histogram) (*mpb.Metric_Histogram, error) {

 // HistogramDataPoints returns a slice of OTLP HistogramDataPoint generated
 // from dPts.
-func HistogramDataPoints(dPts []metricdata.HistogramDataPoint) []*mpb.HistogramDataPoint {
+func HistogramDataPoints[N int64 | float64](dPts []metricdata.HistogramDataPoint[N]) []*mpb.HistogramDataPoint {
 	out := make([]*mpb.HistogramDataPoint, 0, len(dPts))
 	for _, dPt := range dPts {
 		sum := dPt.Sum
--- a/exporters/otlp/otlpmetric/internal/transform/metricdata_test.go
+++ b/exporters/otlp/otlpmetric/internal/transform/metricdata_test.go
@@ -52,7 +52,28 @@ var (

 	minA, maxA, sumA = 2.0, 4.0, 90.0
 	minB, maxB, sumB = 4.0, 150.0, 234.0
-	otelHDP          = []metricdata.HistogramDataPoint{{
+	otelHDPInt64     = []metricdata.HistogramDataPoint[int64]{{
+		Attributes:   alice,
+		StartTime:    start,
+		Time:         end,
+		Count:        30,
+		Bounds:       []float64{1, 5},
+		BucketCounts: []uint64{0, 30, 0},
+		Min:          metricdata.NewExtrema(minA),
+		Max:          metricdata.NewExtrema(maxA),
+		Sum:          sumA,
+	}, {
+		Attributes:   bob,
+		StartTime:    start,
+		Time:         end,
+		Count:        3,
+		Bounds:       []float64{1, 5},
+		BucketCounts: []uint64{0, 1, 2},
+		Min:          metricdata.NewExtrema(minB),
+		Max:          metricdata.NewExtrema(maxB),
+		Sum:          sumB,
+	}}
+	otelHDPFloat64 = []metricdata.HistogramDataPoint[float64]{{
 		Attributes:   alice,
 		StartTime:    start,
 		Time:         end,
@@ -96,14 +117,18 @@ var (
 		Max:               &maxB,
 	}}

-	otelHist = metricdata.Histogram{
+	otelHistInt64 = metricdata.Histogram[int64]{
 		Temporality: metricdata.DeltaTemporality,
-		DataPoints:  otelHDP,
+		DataPoints:  otelHDPInt64,
+	}
+	otelHistFloat64 = metricdata.Histogram[float64]{
+		Temporality: metricdata.DeltaTemporality,
+		DataPoints:  otelHDPFloat64,
 	}
 	invalidTemporality metricdata.Temporality
-	otelHistInvalid    = metricdata.Histogram{
+	otelHistInvalid    = metricdata.Histogram[int64]{
 		Temporality: invalidTemporality,
-		DataPoints:  otelHDP,
+		DataPoints:  otelHDPInt64,
 	}

 	pbHist = &mpb.Histogram{
@@ -215,10 +240,16 @@ var (
 			Data:        otelSumInvalid,
 		},
 		{
-			Name:        "histogram",
+			Name:        "int64-histogram",
 			Description: "Histogram",
 			Unit:        "1",
-			Data:        otelHist,
+			Data:        otelHistInt64,
+		},
+		{
+			Name:        "float64-histogram",
+			Description: "Histogram",
+			Unit:        "1",
+			Data:        otelHistFloat64,
 		},
 		{
 			Name:        "invalid-histogram",
@@ -260,7 +291,13 @@ var (
 			Data:        &mpb.Metric_Sum{Sum: pbSumFloat64},
 		},
 		{
-			Name:        "histogram",
+			Name:        "int64-histogram",
+			Description: "Histogram",
+			Unit:        "1",
+			Data:        &mpb.Metric_Histogram{Histogram: pbHist},
+		},
+		{
+			Name:        "float64-histogram",
 			Description: "Histogram",
 			Unit:        "1",
 			Data:        &mpb.Metric_Histogram{Histogram: pbHist},
@@ -327,12 +364,16 @@ func TestTransformations(t *testing.T) {
 	// errors deep inside the structs).

 	// DataPoint types.
-	assert.Equal(t, pbHDP, HistogramDataPoints(otelHDP))
+	assert.Equal(t, pbHDP, HistogramDataPoints(otelHDPInt64))
+	assert.Equal(t, pbHDP, HistogramDataPoints(otelHDPFloat64))
 	assert.Equal(t, pbDPtsInt64, DataPoints[int64](otelDPtsInt64))
 	require.Equal(t, pbDPtsFloat64, DataPoints[float64](otelDPtsFloat64))

 	// Aggregations.
-	h, err := Histogram(otelHist)
+	h, err := Histogram(otelHistInt64)
+	assert.NoError(t, err)
+	assert.Equal(t, &mpb.Metric_Histogram{Histogram: pbHist}, h)
+	h, err = Histogram(otelHistFloat64)
 	assert.NoError(t, err)
 	assert.Equal(t, &mpb.Metric_Histogram{Histogram: pbHist}, h)
 	h, err = Histogram(otelHistInvalid)
--- a/exporters/prometheus/exporter.go
+++ b/exporters/prometheus/exporter.go
@@ -155,7 +155,9 @@ func (c *collector) Collect(ch chan<- prometheus.Metric) {

 		for _, m := range scopeMetrics.Metrics {
 			switch v := m.Data.(type) {
-			case metricdata.Histogram:
+			case metricdata.Histogram[int64]:
+				addHistogramMetric(ch, v, m, keys, values, c.getName(m), c.metricFamilies)
+			case metricdata.Histogram[float64]:
 				addHistogramMetric(ch, v, m, keys, values, c.getName(m), c.metricFamilies)
 			case metricdata.Sum[int64]:
 				addSumMetric(ch, v, m, keys, values, c.getName(m), c.metricFamilies)
@@ -170,7 +172,7 @@ func (c *collector) Collect(ch chan<- prometheus.Metric) {
 	}
 }

-func addHistogramMetric(ch chan<- prometheus.Metric, histogram metricdata.Histogram, m metricdata.Metrics, ks, vs [2]string, name string, mfs map[string]*dto.MetricFamily) {
+func addHistogramMetric[N int64 | float64](ch chan<- prometheus.Metric, histogram metricdata.Histogram[N], m metricdata.Metrics, ks, vs [2]string, name string, mfs map[string]*dto.MetricFamily) {
 	// TODO(https://github.com/open-telemetry/opentelemetry-go/issues/3163): support exemplars
 	drop, help := validateMetrics(name, m.Description, dto.MetricType_HISTOGRAM.Enum(), mfs)
 	if drop {
--- a/exporters/stdout/stdoutmetric/example_test.go
+++ b/exporters/stdout/stdoutmetric/example_test.go
@@ -81,9 +81,9 @@ var (
 						Name:        "latency",
 						Description: "Time spend processing received requests",
 						Unit:        "ms",
-						Data: metricdata.Histogram{
+						Data: metricdata.Histogram[float64]{
 							Temporality: metricdata.DeltaTemporality,
-							DataPoints: []metricdata.HistogramDataPoint{
+							DataPoints: []metricdata.HistogramDataPoint[float64]{
 								{
 									Attributes:   attribute.NewSet(attribute.String("server", "central")),
 									StartTime:    now,
--- a/exporters/stdout/stdoutmetric/exporter.go
+++ b/exporters/stdout/stdoutmetric/exporter.go
@@ -138,8 +138,13 @@ func redactAggregationTimestamps(orig metricdata.Aggregation) metricdata.Aggrega
 		return metricdata.Gauge[int64]{
 			DataPoints: redactDataPointTimestamps(a.DataPoints),
 		}
-	case metricdata.Histogram:
-		return metricdata.Histogram{
+	case metricdata.Histogram[int64]:
+		return metricdata.Histogram[int64]{
+			Temporality: a.Temporality,
+			DataPoints:  redactHistogramTimestamps(a.DataPoints),
+		}
+	case metricdata.Histogram[float64]:
+		return metricdata.Histogram[float64]{
 			Temporality: a.Temporality,
 			DataPoints:  redactHistogramTimestamps(a.DataPoints),
 		}
@@ -149,10 +154,10 @@ func redactAggregationTimestamps(orig metricdata.Aggregation) metricdata.Aggrega
 	}
 }

-func redactHistogramTimestamps(hdp []metricdata.HistogramDataPoint) []metricdata.HistogramDataPoint {
-	out := make([]metricdata.HistogramDataPoint, len(hdp))
+func redactHistogramTimestamps[T int64 | float64](hdp []metricdata.HistogramDataPoint[T]) []metricdata.HistogramDataPoint[T] {
+	out := make([]metricdata.HistogramDataPoint[T], len(hdp))
 	for i, dp := range hdp {
-		out[i] = metricdata.HistogramDataPoint{
+		out[i] = metricdata.HistogramDataPoint[T]{
 			Attributes:   dp.Attributes,
 			Count:        dp.Count,
 			Sum:          dp.Sum,
--- a/sdk/metric/internal/histogram.go
+++ b/sdk/metric/internal/histogram.go
@@ -141,12 +141,12 @@ func (s *deltaHistogram[N]) Aggregation() metricdata.Aggregation {
 	// Do not allow modification of our copy of bounds.
 	bounds := make([]float64, len(s.bounds))
 	copy(bounds, s.bounds)
-	h := metricdata.Histogram{
+	h := metricdata.Histogram[N]{
 		Temporality: metricdata.DeltaTemporality,
-		DataPoints:  make([]metricdata.HistogramDataPoint, 0, len(s.values)),
+		DataPoints:  make([]metricdata.HistogramDataPoint[N], 0, len(s.values)),
 	}
 	for a, b := range s.values {
-		hdp := metricdata.HistogramDataPoint{
+		hdp := metricdata.HistogramDataPoint[N]{
 			Attributes:   a,
 			StartTime:    s.start,
 			Time:         t,
@@ -204,9 +204,9 @@ func (s *cumulativeHistogram[N]) Aggregation() metricdata.Aggregation {
 	// Do not allow modification of our copy of bounds.
 	bounds := make([]float64, len(s.bounds))
 	copy(bounds, s.bounds)
-	h := metricdata.Histogram{
+	h := metricdata.Histogram[N]{
 		Temporality: metricdata.CumulativeTemporality,
-		DataPoints:  make([]metricdata.HistogramDataPoint, 0, len(s.values)),
+		DataPoints:  make([]metricdata.HistogramDataPoint[N], 0, len(s.values)),
 	}
 	for a, b := range s.values {
 		// The HistogramDataPoint field values returned need to be copies of
@@ -217,7 +217,7 @@ func (s *cumulativeHistogram[N]) Aggregation() metricdata.Aggregation {
 		counts := make([]uint64, len(b.counts))
 		copy(counts, b.counts)

-		hdp := metricdata.HistogramDataPoint{
+		hdp := metricdata.HistogramDataPoint[N]{
 			Attributes:   a,
 			StartTime:    s.start,
 			Time:         t,
--- a/sdk/metric/internal/histogram_test.go
+++ b/sdk/metric/internal/histogram_test.go
@@ -49,31 +49,31 @@ func testHistogram[N int64 | float64](t *testing.T) {
 	}

 	incr := monoIncr
-	eFunc := deltaHistExpecter(incr)
+	eFunc := deltaHistExpecter[N](incr)
 	t.Run("Delta", tester.Run(NewDeltaHistogram[N](histConf), incr, eFunc))
-	eFunc = cumuHistExpecter(incr)
+	eFunc = cumuHistExpecter[N](incr)
 	t.Run("Cumulative", tester.Run(NewCumulativeHistogram[N](histConf), incr, eFunc))
 }

-func deltaHistExpecter(incr setMap) expectFunc {
-	h := metricdata.Histogram{Temporality: metricdata.DeltaTemporality}
+func deltaHistExpecter[N int64 | float64](incr setMap) expectFunc {
+	h := metricdata.Histogram[N]{Temporality: metricdata.DeltaTemporality}
 	return func(m int) metricdata.Aggregation {
-		h.DataPoints = make([]metricdata.HistogramDataPoint, 0, len(incr))
+		h.DataPoints = make([]metricdata.HistogramDataPoint[N], 0, len(incr))
 		for a, v := range incr {
-			h.DataPoints = append(h.DataPoints, hPoint(a, float64(v), uint64(m)))
+			h.DataPoints = append(h.DataPoints, hPoint[N](a, float64(v), uint64(m)))
 		}
 		return h
 	}
 }

-func cumuHistExpecter(incr setMap) expectFunc {
+func cumuHistExpecter[N int64 | float64](incr setMap) expectFunc {
 	var cycle int
-	h := metricdata.Histogram{Temporality: metricdata.CumulativeTemporality}
+	h := metricdata.Histogram[N]{Temporality: metricdata.CumulativeTemporality}
 	return func(m int) metricdata.Aggregation {
 		cycle++
-		h.DataPoints = make([]metricdata.HistogramDataPoint, 0, len(incr))
+		h.DataPoints = make([]metricdata.HistogramDataPoint[N], 0, len(incr))
 		for a, v := range incr {
-			h.DataPoints = append(h.DataPoints, hPoint(a, float64(v), uint64(cycle*m)))
+			h.DataPoints = append(h.DataPoints, hPoint[N](a, float64(v), uint64(cycle*m)))
 		}
 		return h
 	}
@@ -81,11 +81,11 @@ func cumuHistExpecter(incr setMap) expectFunc {

 // hPoint returns an HistogramDataPoint that started and ended now with multi
 // number of measurements values v. It includes a min and max (set to v).
-func hPoint(a attribute.Set, v float64, multi uint64) metricdata.HistogramDataPoint {
+func hPoint[N int64 | float64](a attribute.Set, v float64, multi uint64) metricdata.HistogramDataPoint[N] {
 	idx := sort.SearchFloat64s(bounds, v)
 	counts := make([]uint64, len(bounds)+1)
 	counts[idx] += multi
-	return metricdata.HistogramDataPoint{
+	return metricdata.HistogramDataPoint[N]{
 		Attributes:   a,
 		StartTime:    now(),
 		Time:         now(),
@@ -128,7 +128,7 @@ func testHistImmutableBounds[N int64 | float64](newA func(aggregation.ExplicitBu
 		assert.Equal(t, cpB, getBounds(a), "modifying the bounds argument should not change the bounds")

 		a.Aggregate(5, alice)
-		hdp := a.Aggregation().(metricdata.Histogram).DataPoints[0]
+		hdp := a.Aggregation().(metricdata.Histogram[N]).DataPoints[0]
 		hdp.Bounds[1] = 10
 		assert.Equal(t, cpB, getBounds(a), "modifying the Aggregation bounds should not change the bounds")
 	}
@@ -155,7 +155,7 @@ func TestHistogramImmutableBounds(t *testing.T) {
 func TestCumulativeHistogramImutableCounts(t *testing.T) {
 	a := NewCumulativeHistogram[int64](histConf)
 	a.Aggregate(5, alice)
-	hdp := a.Aggregation().(metricdata.Histogram).DataPoints[0]
+	hdp := a.Aggregation().(metricdata.Histogram[int64]).DataPoints[0]

 	cumuH := a.(*cumulativeHistogram[int64])
 	require.Equal(t, hdp.BucketCounts, cumuH.values[alice].counts)
@@ -173,8 +173,8 @@ func TestDeltaHistogramReset(t *testing.T) {
 	assert.Nil(t, a.Aggregation())

 	a.Aggregate(1, alice)
-	expect := metricdata.Histogram{Temporality: metricdata.DeltaTemporality}
-	expect.DataPoints = []metricdata.HistogramDataPoint{hPoint(alice, 1, 1)}
+	expect := metricdata.Histogram[int64]{Temporality: metricdata.DeltaTemporality}
+	expect.DataPoints = []metricdata.HistogramDataPoint[int64]{hPoint[int64](alice, 1, 1)}
 	metricdatatest.AssertAggregationsEqual(t, expect, a.Aggregation())

 	// The attr set should be forgotten once Aggregations is called.
@@ -183,7 +183,7 @@ func TestDeltaHistogramReset(t *testing.T) {

 	// Aggregating another set should not affect the original (alice).
 	a.Aggregate(1, bob)
-	expect.DataPoints = []metricdata.HistogramDataPoint{hPoint(bob, 1, 1)}
+	expect.DataPoints = []metricdata.HistogramDataPoint[int64]{hPoint[int64](bob, 1, 1)}
 	metricdatatest.AssertAggregationsEqual(t, expect, a.Aggregation())
 }

--- a/sdk/metric/meter_test.go
+++ b/sdk/metric/meter_test.go
@@ -382,9 +382,9 @@ func TestMeterCreatesInstruments(t *testing.T) {
 			},
 			want: metricdata.Metrics{
 				Name: "histogram",
-				Data: metricdata.Histogram{
+				Data: metricdata.Histogram[int64]{
 					Temporality: metricdata.CumulativeTemporality,
-					DataPoints: []metricdata.HistogramDataPoint{
+					DataPoints: []metricdata.HistogramDataPoint[int64]{
 						{
 							Attributes:   attribute.Set{},
 							Count:        1,
@@ -446,9 +446,9 @@ func TestMeterCreatesInstruments(t *testing.T) {
 			},
 			want: metricdata.Metrics{
 				Name: "histogram",
-				Data: metricdata.Histogram{
+				Data: metricdata.Histogram[float64]{
 					Temporality: metricdata.CumulativeTemporality,
-					DataPoints: []metricdata.HistogramDataPoint{
+					DataPoints: []metricdata.HistogramDataPoint[float64]{
 						{
 							Attributes:   attribute.Set{},
 							Count:        1,
@@ -1124,8 +1124,8 @@ func testAttributeFilter(temporality metricdata.Temporality) func(*testing.T) {
 			},
 			wantMetric: metricdata.Metrics{
 				Name: "sfhistogram",
-				Data: metricdata.Histogram{
-					DataPoints: []metricdata.HistogramDataPoint{
+				Data: metricdata.Histogram[float64]{
+					DataPoints: []metricdata.HistogramDataPoint[float64]{
 						{
 							Attributes:   attribute.NewSet(attribute.String("foo", "bar")),
 							Bounds:       []float64{0, 5, 10, 25, 50, 75, 100, 250, 500, 750, 1000, 2500, 5000, 7500, 10000},
@@ -1206,8 +1206,8 @@ func testAttributeFilter(temporality metricdata.Temporality) func(*testing.T) {
 			},
 			wantMetric: metricdata.Metrics{
 				Name: "sihistogram",
-				Data: metricdata.Histogram{
-					DataPoints: []metricdata.HistogramDataPoint{
+				Data: metricdata.Histogram[int64]{
+					DataPoints: []metricdata.HistogramDataPoint[int64]{
 						{
 							Attributes:   attribute.NewSet(attribute.String("foo", "bar")),
 							Bounds:       []float64{0, 5, 10, 25, 50, 75, 100, 250, 500, 750, 1000, 2500, 5000, 7500, 10000},
--- a/sdk/metric/metricdata/data.go
+++ b/sdk/metric/metricdata/data.go
@@ -59,7 +59,8 @@ type Aggregation interface {

 // Gauge represents a measurement of the current value of an instrument.
 type Gauge[N int64 | float64] struct {
-	// DataPoints reprents individual aggregated measurements with unique Attributes.
+	// DataPoints are the individual aggregated measurements with unique
+	// Attributes.
 	DataPoints []DataPoint[N]
 }

@@ -67,7 +68,8 @@ func (Gauge[N]) privateAggregation() {}

 // Sum represents the sum of all measurements of values from an instrument.
 type Sum[N int64 | float64] struct {
-	// DataPoints reprents individual aggregated measurements with unique Attributes.
+	// DataPoints are the individual aggregated measurements with unique
+	// Attributes.
 	DataPoints []DataPoint[N]
 	// Temporality describes if the aggregation is reported as the change from the
 	// last report time, or the cumulative changes since a fixed start time.
@@ -89,21 +91,25 @@ type DataPoint[N int64 | float64] struct {
 	Time time.Time `json:",omitempty"`
 	// Value is the value of this data point.
 	Value N
+
+	// Exemplars is the sampled Exemplars collected during the timeseries.
+	Exemplars []Exemplar[N] `json:",omitempty"`
 }

 // Histogram represents the histogram of all measurements of values from an instrument.
-type Histogram struct {
-	// DataPoints reprents individual aggregated measurements with unique Attributes.
-	DataPoints []HistogramDataPoint
+type Histogram[N int64 | float64] struct {
+	// DataPoints are the individual aggregated measurements with unique
+	// Attributes.
+	DataPoints []HistogramDataPoint[N]
 	// Temporality describes if the aggregation is reported as the change from the
 	// last report time, or the cumulative changes since a fixed start time.
 	Temporality Temporality
 }

-func (Histogram) privateAggregation() {}
+func (Histogram[N]) privateAggregation() {}

 // HistogramDataPoint is a single histogram data point in a timeseries.
-type HistogramDataPoint struct {
+type HistogramDataPoint[N int64 | float64] struct {
 	// Attributes is the set of key value pairs that uniquely identify the
 	// timeseries.
 	Attributes attribute.Set
@@ -126,6 +132,9 @@ type HistogramDataPoint struct {
 	Max Extrema
 	// Sum is the sum of the values recorded.
 	Sum float64
+
+	// Exemplars is the sampled Exemplars collected during the timeseries.
+	Exemplars []Exemplar[N] `json:",omitempty"`
 }

 // Extrema is the minimum or maximum value of a dataset.
@@ -144,3 +153,22 @@ func NewExtrema(v float64) Extrema {
 func (e Extrema) Value() (v float64, defined bool) {
 	return e.value, e.valid
 }
+
+// Exemplar is a measurement sampled from a timeseries providing a typical
+// example.
+type Exemplar[N int64 | float64] struct {
+	// FilteredAttributes are the attributes recorded with the measurement but
+	// filtered out of the timeseries' aggregated data.
+	FilteredAttributes []attribute.KeyValue
+	// Time is the time when the measurement was recorded.
+	Time time.Time
+	// Value is the measured value.
+	Value N
+	// SpanID is the ID of the span that was active during the measurement. If
+	// no span was active or the span was not sampled this will be empty.
+	SpanID []byte `json:",omitempty"`
+	// TraceID is the ID of the trace the active span belonged to during the
+	// measurement. If no span was active or the span was not sampled this will
+	// be empty.
+	TraceID []byte `json:",omitempty"`
+}
--- a/sdk/metric/metricdata/metricdatatest/assertion.go
+++ b/sdk/metric/metricdata/metricdatatest/assertion.go
@@ -30,14 +30,18 @@ type Datatypes interface {
 		metricdata.DataPoint[int64] |
 		metricdata.Gauge[float64] |
 		metricdata.Gauge[int64] |
-		metricdata.Histogram |
-		metricdata.HistogramDataPoint |
+		metricdata.Histogram[float64] |
+		metricdata.Histogram[int64] |
+		metricdata.HistogramDataPoint[float64] |
+		metricdata.HistogramDataPoint[int64] |
 		metricdata.Extrema |
 		metricdata.Metrics |
 		metricdata.ResourceMetrics |
 		metricdata.ScopeMetrics |
 		metricdata.Sum[float64] |
-		metricdata.Sum[int64]
+		metricdata.Sum[int64] |
+		metricdata.Exemplar[float64] |
+		metricdata.Exemplar[int64]

 	// Interface types are not allowed in union types, therefore the
 	// Aggregation and Value type from metricdata are not included here.
@@ -45,6 +49,15 @@ type Datatypes interface {

 type config struct {
 	ignoreTimestamp bool
+	ignoreExemplars bool
+}
+
+func newConfig(opts []Option) config {
+	var cfg config
+	for _, opt := range opts {
+		cfg = opt.apply(cfg)
+	}
+	return cfg
 }

 // Option allows for fine grain control over how AssertEqual operates.
@@ -66,21 +79,30 @@ func IgnoreTimestamp() Option {
 	})
 }

+// IgnoreExemplars disables checking if Exemplars are different.
+func IgnoreExemplars() Option {
+	return fnOption(func(cfg config) config {
+		cfg.ignoreExemplars = true
+		return cfg
+	})
+}
+
 // AssertEqual asserts that the two concrete data-types from the metricdata
 // package are equal.
 func AssertEqual[T Datatypes](t *testing.T, expected, actual T, opts ...Option) bool {
 	t.Helper()

-	cfg := config{}
-	for _, opt := range opts {
-		cfg = opt.apply(cfg)
-	}
+	cfg := newConfig(opts)

 	// Generic types cannot be type asserted. Use an interface instead.
 	aIface := interface{}(actual)

 	var r []string
 	switch e := interface{}(expected).(type) {
+	case metricdata.Exemplar[int64]:
+		r = equalExemplars(e, aIface.(metricdata.Exemplar[int64]), cfg)
+	case metricdata.Exemplar[float64]:
+		r = equalExemplars(e, aIface.(metricdata.Exemplar[float64]), cfg)
 	case metricdata.DataPoint[int64]:
 		r = equalDataPoints(e, aIface.(metricdata.DataPoint[int64]), cfg)
 	case metricdata.DataPoint[float64]:
@@ -89,10 +111,14 @@ func AssertEqual[T Datatypes](t *testing.T, expected, actual T, opts ...Option)
 		r = equalGauges(e, aIface.(metricdata.Gauge[int64]), cfg)
 	case metricdata.Gauge[float64]:
 		r = equalGauges(e, aIface.(metricdata.Gauge[float64]), cfg)
-	case metricdata.Histogram:
-		r = equalHistograms(e, aIface.(metricdata.Histogram), cfg)
-	case metricdata.HistogramDataPoint:
-		r = equalHistogramDataPoints(e, aIface.(metricdata.HistogramDataPoint), cfg)
+	case metricdata.Histogram[float64]:
+		r = equalHistograms(e, aIface.(metricdata.Histogram[float64]), cfg)
+	case metricdata.Histogram[int64]:
+		r = equalHistograms(e, aIface.(metricdata.Histogram[int64]), cfg)
+	case metricdata.HistogramDataPoint[float64]:
+		r = equalHistogramDataPoints(e, aIface.(metricdata.HistogramDataPoint[float64]), cfg)
+	case metricdata.HistogramDataPoint[int64]:
+		r = equalHistogramDataPoints(e, aIface.(metricdata.HistogramDataPoint[int64]), cfg)
 	case metricdata.Extrema:
 		r = equalExtrema(e, aIface.(metricdata.Extrema), cfg)
 	case metricdata.Metrics:
@@ -122,11 +148,7 @@ func AssertEqual[T Datatypes](t *testing.T, expected, actual T, opts ...Option)
 func AssertAggregationsEqual(t *testing.T, expected, actual metricdata.Aggregation, opts ...Option) bool {
 	t.Helper()

-	cfg := config{}
-	for _, opt := range opts {
-		cfg = opt.apply(cfg)
-	}
-
+	cfg := newConfig(opts)
 	if r := equalAggregations(expected, actual, cfg); len(r) > 0 {
 		t.Error(r)
 		return false
@@ -141,6 +163,10 @@ func AssertHasAttributes[T Datatypes](t *testing.T, actual T, attrs ...attribute
 	var reasons []string

 	switch e := interface{}(actual).(type) {
+	case metricdata.Exemplar[int64]:
+		reasons = hasAttributesExemplars(e, attrs...)
+	case metricdata.Exemplar[float64]:
+		reasons = hasAttributesExemplars(e, attrs...)
 	case metricdata.DataPoint[int64]:
 		reasons = hasAttributesDataPoints(e, attrs...)
 	case metricdata.DataPoint[float64]:
@@ -153,11 +179,15 @@ func AssertHasAttributes[T Datatypes](t *testing.T, actual T, attrs ...attribute
 		reasons = hasAttributesSum(e, attrs...)
 	case metricdata.Sum[float64]:
 		reasons = hasAttributesSum(e, attrs...)
-	case metricdata.HistogramDataPoint:
+	case metricdata.HistogramDataPoint[int64]:
+		reasons = hasAttributesHistogramDataPoints(e, attrs...)
+	case metricdata.HistogramDataPoint[float64]:
 		reasons = hasAttributesHistogramDataPoints(e, attrs...)
 	case metricdata.Extrema:
 		// Nothing to check.
-	case metricdata.Histogram:
+	case metricdata.Histogram[int64]:
+		reasons = hasAttributesHistogram(e, attrs...)
+	case metricdata.Histogram[float64]:
 		reasons = hasAttributesHistogram(e, attrs...)
 	case metricdata.Metrics:
 		reasons = hasAttributesMetrics(e, attrs...)
--- a/sdk/metric/metricdata/metricdatatest/assertion_fail_test.go
+++ b/sdk/metric/metricdata/metricdatatest/assertion_fail_test.go
@@ -38,15 +38,19 @@ func TestFailAssertEqual(t *testing.T) {
 	t.Run("ResourceMetrics", testFailDatatype(resourceMetricsA, resourceMetricsB))
 	t.Run("ScopeMetrics", testFailDatatype(scopeMetricsA, scopeMetricsB))
 	t.Run("Metrics", testFailDatatype(metricsA, metricsB))
-	t.Run("Histogram", testFailDatatype(histogramA, histogramB))
+	t.Run("HistogramInt64", testFailDatatype(histogramInt64A, histogramInt64B))
+	t.Run("HistogramFloat64", testFailDatatype(histogramFloat64A, histogramFloat64B))
 	t.Run("SumInt64", testFailDatatype(sumInt64A, sumInt64B))
 	t.Run("SumFloat64", testFailDatatype(sumFloat64A, sumFloat64B))
 	t.Run("GaugeInt64", testFailDatatype(gaugeInt64A, gaugeInt64B))
 	t.Run("GaugeFloat64", testFailDatatype(gaugeFloat64A, gaugeFloat64B))
-	t.Run("HistogramDataPoint", testFailDatatype(histogramDataPointA, histogramDataPointB))
+	t.Run("HistogramDataPointInt64", testFailDatatype(histogramDataPointInt64A, histogramDataPointInt64B))
+	t.Run("HistogramDataPointFloat64", testFailDatatype(histogramDataPointFloat64A, histogramDataPointFloat64B))
 	t.Run("DataPointInt64", testFailDatatype(dataPointInt64A, dataPointInt64B))
 	t.Run("DataPointFloat64", testFailDatatype(dataPointFloat64A, dataPointFloat64B))
-
+	t.Run("ExemplarInt64", testFailDatatype(exemplarInt64A, exemplarInt64B))
+	t.Run("ExemplarFloat64", testFailDatatype(exemplarFloat64A, exemplarFloat64B))
+	t.Run("Extrema", testFailDatatype(minA, minB))
 }

 func TestFailAssertAggregationsEqual(t *testing.T) {
@@ -57,20 +61,23 @@ func TestFailAssertAggregationsEqual(t *testing.T) {
 	AssertAggregationsEqual(t, sumFloat64A, sumFloat64B)
 	AssertAggregationsEqual(t, gaugeInt64A, gaugeInt64B)
 	AssertAggregationsEqual(t, gaugeFloat64A, gaugeFloat64B)
-	AssertAggregationsEqual(t, histogramA, histogramB)
+	AssertAggregationsEqual(t, histogramInt64A, histogramInt64B)
+	AssertAggregationsEqual(t, histogramFloat64A, histogramFloat64B)
 }

 func TestFailAssertAttribute(t *testing.T) {
+	AssertHasAttributes(t, exemplarInt64A, attribute.Bool("A", false))
+	AssertHasAttributes(t, exemplarFloat64A, attribute.Bool("B", true))
 	AssertHasAttributes(t, dataPointInt64A, attribute.Bool("A", false))
 	AssertHasAttributes(t, dataPointFloat64A, attribute.Bool("B", true))
 	AssertHasAttributes(t, gaugeInt64A, attribute.Bool("A", false))
 	AssertHasAttributes(t, gaugeFloat64A, attribute.Bool("B", true))
 	AssertHasAttributes(t, sumInt64A, attribute.Bool("A", false))
 	AssertHasAttributes(t, sumFloat64A, attribute.Bool("B", true))
-	AssertHasAttributes(t, histogramDataPointA, attribute.Bool("A", false))
-	AssertHasAttributes(t, histogramDataPointA, attribute.Bool("B", true))
-	AssertHasAttributes(t, histogramA, attribute.Bool("A", false))
-	AssertHasAttributes(t, histogramA, attribute.Bool("B", true))
+	AssertHasAttributes(t, histogramDataPointInt64A, attribute.Bool("A", false))
+	AssertHasAttributes(t, histogramDataPointFloat64A, attribute.Bool("B", true))
+	AssertHasAttributes(t, histogramInt64A, attribute.Bool("A", false))
+	AssertHasAttributes(t, histogramFloat64A, attribute.Bool("B", true))
 	AssertHasAttributes(t, metricsA, attribute.Bool("A", false))
 	AssertHasAttributes(t, metricsA, attribute.Bool("B", true))
 	AssertHasAttributes(t, resourceMetricsA, attribute.Bool("A", false))
--- a/sdk/metric/metricdata/metricdatatest/assertion_test.go
+++ b/sdk/metric/metricdata/metricdatatest/assertion_test.go
@@ -30,53 +30,110 @@ var (
 	attrA = attribute.NewSet(attribute.Bool("A", true))
 	attrB = attribute.NewSet(attribute.Bool("B", true))

+	fltrAttrA = []attribute.KeyValue{attribute.Bool("filter A", true)}
+	fltrAttrB = []attribute.KeyValue{attribute.Bool("filter B", true)}
+
 	startA = time.Now()
 	startB = startA.Add(time.Millisecond)
 	endA   = startA.Add(time.Second)
 	endB   = startB.Add(time.Second)

+	spanIDA  = []byte{0, 0, 0, 0, 0, 0, 0, 1}
+	spanIDB  = []byte{0, 0, 0, 0, 0, 0, 0, 2}
+	traceIDA = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
+	traceIDB = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2}
+
+	exemplarInt64A = metricdata.Exemplar[int64]{
+		FilteredAttributes: fltrAttrA,
+		Time:               endA,
+		Value:              -10,
+		SpanID:             spanIDA,
+		TraceID:            traceIDA,
+	}
+	exemplarFloat64A = metricdata.Exemplar[float64]{
+		FilteredAttributes: fltrAttrA,
+		Time:               endA,
+		Value:              -10.0,
+		SpanID:             spanIDA,
+		TraceID:            traceIDA,
+	}
+	exemplarInt64B = metricdata.Exemplar[int64]{
+		FilteredAttributes: fltrAttrB,
+		Time:               endB,
+		Value:              12,
+		SpanID:             spanIDB,
+		TraceID:            traceIDB,
+	}
+	exemplarFloat64B = metricdata.Exemplar[float64]{
+		FilteredAttributes: fltrAttrB,
+		Time:               endB,
+		Value:              12.0,
+		SpanID:             spanIDB,
+		TraceID:            traceIDB,
+	}
+	exemplarInt64C = metricdata.Exemplar[int64]{
+		FilteredAttributes: fltrAttrA,
+		Time:               endB,
+		Value:              -10,
+		SpanID:             spanIDA,
+		TraceID:            traceIDA,
+	}
+	exemplarFloat64C = metricdata.Exemplar[float64]{
+		FilteredAttributes: fltrAttrA,
+		Time:               endB,
+		Value:              -10.0,
+		SpanID:             spanIDA,
+		TraceID:            traceIDA,
+	}
+
 	dataPointInt64A = metricdata.DataPoint[int64]{
 		Attributes: attrA,
 		StartTime:  startA,
 		Time:       endA,
 		Value:      -1,
+		Exemplars:  []metricdata.Exemplar[int64]{exemplarInt64A},
 	}
 	dataPointFloat64A = metricdata.DataPoint[float64]{
 		Attributes: attrA,
 		StartTime:  startA,
 		Time:       endA,
 		Value:      -1.0,
+		Exemplars:  []metricdata.Exemplar[float64]{exemplarFloat64A},
 	}
 	dataPointInt64B = metricdata.DataPoint[int64]{
 		Attributes: attrB,
 		StartTime:  startB,
 		Time:       endB,
 		Value:      2,
+		Exemplars:  []metricdata.Exemplar[int64]{exemplarInt64B},
 	}
 	dataPointFloat64B = metricdata.DataPoint[float64]{
 		Attributes: attrB,
 		StartTime:  startB,
 		Time:       endB,
 		Value:      2.0,
+		Exemplars:  []metricdata.Exemplar[float64]{exemplarFloat64B},
 	}
 	dataPointInt64C = metricdata.DataPoint[int64]{
 		Attributes: attrA,
 		StartTime:  startB,
 		Time:       endB,
 		Value:      -1,
+		Exemplars:  []metricdata.Exemplar[int64]{exemplarInt64C},
 	}
 	dataPointFloat64C = metricdata.DataPoint[float64]{
 		Attributes: attrA,
 		StartTime:  startB,
 		Time:       endB,
 		Value:      -1.0,
+		Exemplars:  []metricdata.Exemplar[float64]{exemplarFloat64C},
 	}

 	minA       = metricdata.NewExtrema(-1.)
 	minB, maxB = metricdata.NewExtrema(3.), metricdata.NewExtrema(99.)
 	minC       = metricdata.NewExtrema(-1.)

-	histogramDataPointA = metricdata.HistogramDataPoint{
+	histogramDataPointInt64A = metricdata.HistogramDataPoint[int64]{
 		Attributes:   attrA,
 		StartTime:    startA,
 		Time:         endA,
@@ -85,8 +142,20 @@ var (
 		BucketCounts: []uint64{1, 1},
 		Min:          minA,
 		Sum:          2,
+		Exemplars:    []metricdata.Exemplar[int64]{exemplarInt64A},
 	}
-	histogramDataPointB = metricdata.HistogramDataPoint{
+	histogramDataPointFloat64A = metricdata.HistogramDataPoint[float64]{
+		Attributes:   attrA,
+		StartTime:    startA,
+		Time:         endA,
+		Count:        2,
+		Bounds:       []float64{0, 10},
+		BucketCounts: []uint64{1, 1},
+		Min:          minA,
+		Sum:          2,
+		Exemplars:    []metricdata.Exemplar[float64]{exemplarFloat64A},
+	}
+	histogramDataPointInt64B = metricdata.HistogramDataPoint[int64]{
 		Attributes:   attrB,
 		StartTime:    startB,
 		Time:         endB,
@@ -96,8 +165,21 @@ var (
 		Max:          maxB,
 		Min:          minB,
 		Sum:          3,
+		Exemplars:    []metricdata.Exemplar[int64]{exemplarInt64B},
 	}
-	histogramDataPointC = metricdata.HistogramDataPoint{
+	histogramDataPointFloat64B = metricdata.HistogramDataPoint[float64]{
+		Attributes:   attrB,
+		StartTime:    startB,
+		Time:         endB,
+		Count:        3,
+		Bounds:       []float64{0, 10, 100},
+		BucketCounts: []uint64{1, 1, 1},
+		Max:          maxB,
+		Min:          minB,
+		Sum:          3,
+		Exemplars:    []metricdata.Exemplar[float64]{exemplarFloat64B},
+	}
+	histogramDataPointInt64C = metricdata.HistogramDataPoint[int64]{
 		Attributes:   attrA,
 		StartTime:    startB,
 		Time:         endB,
@@ -106,6 +188,18 @@ var (
 		BucketCounts: []uint64{1, 1},
 		Min:          minC,
 		Sum:          2,
+		Exemplars:    []metricdata.Exemplar[int64]{exemplarInt64C},
+	}
+	histogramDataPointFloat64C = metricdata.HistogramDataPoint[float64]{
+		Attributes:   attrA,
+		StartTime:    startB,
+		Time:         endB,
+		Count:        2,
+		Bounds:       []float64{0, 10},
+		BucketCounts: []uint64{1, 1},
+		Min:          minC,
+		Sum:          2,
+		Exemplars:    []metricdata.Exemplar[float64]{exemplarFloat64C},
 	}

 	gaugeInt64A = metricdata.Gauge[int64]{
@@ -158,17 +252,29 @@ var (
 		DataPoints:  []metricdata.DataPoint[float64]{dataPointFloat64C},
 	}

-	histogramA = metricdata.Histogram{
+	histogramInt64A = metricdata.Histogram[int64]{
 		Temporality: metricdata.CumulativeTemporality,
-		DataPoints:  []metricdata.HistogramDataPoint{histogramDataPointA},
+		DataPoints:  []metricdata.HistogramDataPoint[int64]{histogramDataPointInt64A},
 	}
-	histogramB = metricdata.Histogram{
+	histogramFloat64A = metricdata.Histogram[float64]{
+		Temporality: metricdata.CumulativeTemporality,
+		DataPoints:  []metricdata.HistogramDataPoint[float64]{histogramDataPointFloat64A},
+	}
+	histogramInt64B = metricdata.Histogram[int64]{
 		Temporality: metricdata.DeltaTemporality,
-		DataPoints:  []metricdata.HistogramDataPoint{histogramDataPointB},
+		DataPoints:  []metricdata.HistogramDataPoint[int64]{histogramDataPointInt64B},
 	}
-	histogramC = metricdata.Histogram{
+	histogramFloat64B = metricdata.Histogram[float64]{
+		Temporality: metricdata.DeltaTemporality,
+		DataPoints:  []metricdata.HistogramDataPoint[float64]{histogramDataPointFloat64B},
+	}
+	histogramInt64C = metricdata.Histogram[int64]{
 		Temporality: metricdata.CumulativeTemporality,
-		DataPoints:  []metricdata.HistogramDataPoint{histogramDataPointC},
+		DataPoints:  []metricdata.HistogramDataPoint[int64]{histogramDataPointInt64C},
+	}
+	histogramFloat64C = metricdata.Histogram[float64]{
+		Temporality: metricdata.CumulativeTemporality,
+		DataPoints:  []metricdata.HistogramDataPoint[float64]{histogramDataPointFloat64C},
 	}

 	metricsA = metricdata.Metrics{
@@ -224,7 +330,7 @@ func testDatatype[T Datatypes](a, b T, f equalFunc[T]) func(*testing.T) {
 		AssertEqual(t, a, a)
 		AssertEqual(t, b, b)

-		r := f(a, b, config{})
+		r := f(a, b, newConfig(nil))
 		assert.Greaterf(t, len(r), 0, "%v == %v", a, b)
 	}
 }
@@ -234,8 +340,20 @@ func testDatatypeIgnoreTime[T Datatypes](a, b T, f equalFunc[T]) func(*testing.T
 		AssertEqual(t, a, a)
 		AssertEqual(t, b, b)

-		r := f(a, b, config{ignoreTimestamp: true})
-		assert.Equalf(t, len(r), 0, "%v == %v", a, b)
+		c := newConfig([]Option{IgnoreTimestamp()})
+		r := f(a, b, c)
+		assert.Len(t, r, 0, "unexpected inequality")
+	}
+}
+
+func testDatatypeIgnoreExemplars[T Datatypes](a, b T, f equalFunc[T]) func(*testing.T) {
+	return func(t *testing.T) {
+		AssertEqual(t, a, a)
+		AssertEqual(t, b, b)
+
+		c := newConfig([]Option{IgnoreExemplars()})
+		r := f(a, b, c)
+		assert.Len(t, r, 0, "unexpected inequality")
 	}
 }

@@ -243,30 +361,56 @@ func TestAssertEqual(t *testing.T) {
 	t.Run("ResourceMetrics", testDatatype(resourceMetricsA, resourceMetricsB, equalResourceMetrics))
 	t.Run("ScopeMetrics", testDatatype(scopeMetricsA, scopeMetricsB, equalScopeMetrics))
 	t.Run("Metrics", testDatatype(metricsA, metricsB, equalMetrics))
-	t.Run("Histogram", testDatatype(histogramA, histogramB, equalHistograms))
+	t.Run("HistogramInt64", testDatatype(histogramInt64A, histogramInt64B, equalHistograms[int64]))
+	t.Run("HistogramFloat64", testDatatype(histogramFloat64A, histogramFloat64B, equalHistograms[float64]))
 	t.Run("SumInt64", testDatatype(sumInt64A, sumInt64B, equalSums[int64]))
 	t.Run("SumFloat64", testDatatype(sumFloat64A, sumFloat64B, equalSums[float64]))
 	t.Run("GaugeInt64", testDatatype(gaugeInt64A, gaugeInt64B, equalGauges[int64]))
 	t.Run("GaugeFloat64", testDatatype(gaugeFloat64A, gaugeFloat64B, equalGauges[float64]))
-	t.Run("HistogramDataPoint", testDatatype(histogramDataPointA, histogramDataPointB, equalHistogramDataPoints))
+	t.Run("HistogramDataPointInt64", testDatatype(histogramDataPointInt64A, histogramDataPointInt64B, equalHistogramDataPoints[int64]))
+	t.Run("HistogramDataPointFloat64", testDatatype(histogramDataPointFloat64A, histogramDataPointFloat64B, equalHistogramDataPoints[float64]))
 	t.Run("DataPointInt64", testDatatype(dataPointInt64A, dataPointInt64B, equalDataPoints[int64]))
 	t.Run("DataPointFloat64", testDatatype(dataPointFloat64A, dataPointFloat64B, equalDataPoints[float64]))
 	t.Run("Extrema", testDatatype(minA, minB, equalExtrema))
+	t.Run("ExemplarInt64", testDatatype(exemplarInt64A, exemplarInt64B, equalExemplars[int64]))
+	t.Run("ExemplarFloat64", testDatatype(exemplarFloat64A, exemplarFloat64B, equalExemplars[float64]))
 }

 func TestAssertEqualIgnoreTime(t *testing.T) {
 	t.Run("ResourceMetrics", testDatatypeIgnoreTime(resourceMetricsA, resourceMetricsC, equalResourceMetrics))
 	t.Run("ScopeMetrics", testDatatypeIgnoreTime(scopeMetricsA, scopeMetricsC, equalScopeMetrics))
 	t.Run("Metrics", testDatatypeIgnoreTime(metricsA, metricsC, equalMetrics))
-	t.Run("Histogram", testDatatypeIgnoreTime(histogramA, histogramC, equalHistograms))
+	t.Run("HistogramInt64", testDatatypeIgnoreTime(histogramInt64A, histogramInt64C, equalHistograms[int64]))
+	t.Run("HistogramFloat64", testDatatypeIgnoreTime(histogramFloat64A, histogramFloat64C, equalHistograms[float64]))
 	t.Run("SumInt64", testDatatypeIgnoreTime(sumInt64A, sumInt64C, equalSums[int64]))
 	t.Run("SumFloat64", testDatatypeIgnoreTime(sumFloat64A, sumFloat64C, equalSums[float64]))
 	t.Run("GaugeInt64", testDatatypeIgnoreTime(gaugeInt64A, gaugeInt64C, equalGauges[int64]))
 	t.Run("GaugeFloat64", testDatatypeIgnoreTime(gaugeFloat64A, gaugeFloat64C, equalGauges[float64]))
-	t.Run("HistogramDataPoint", testDatatypeIgnoreTime(histogramDataPointA, histogramDataPointC, equalHistogramDataPoints))
+	t.Run("HistogramDataPointInt64", testDatatypeIgnoreTime(histogramDataPointInt64A, histogramDataPointInt64C, equalHistogramDataPoints[int64]))
+	t.Run("HistogramDataPointFloat64", testDatatypeIgnoreTime(histogramDataPointFloat64A, histogramDataPointFloat64C, equalHistogramDataPoints[float64]))
 	t.Run("DataPointInt64", testDatatypeIgnoreTime(dataPointInt64A, dataPointInt64C, equalDataPoints[int64]))
 	t.Run("DataPointFloat64", testDatatypeIgnoreTime(dataPointFloat64A, dataPointFloat64C, equalDataPoints[float64]))
 	t.Run("Extrema", testDatatypeIgnoreTime(minA, minC, equalExtrema))
+	t.Run("ExemplarInt64", testDatatypeIgnoreTime(exemplarInt64A, exemplarInt64C, equalExemplars[int64]))
+	t.Run("ExemplarFloat64", testDatatypeIgnoreTime(exemplarFloat64A, exemplarFloat64C, equalExemplars[float64]))
+}
+
+func TestAssertEqualIgnoreExemplars(t *testing.T) {
+	hdpInt64 := histogramDataPointInt64A
+	hdpInt64.Exemplars = []metricdata.Exemplar[int64]{exemplarInt64B}
+	t.Run("HistogramDataPointInt64", testDatatypeIgnoreExemplars(histogramDataPointInt64A, hdpInt64, equalHistogramDataPoints[int64]))
+
+	hdpFloat64 := histogramDataPointFloat64A
+	hdpFloat64.Exemplars = []metricdata.Exemplar[float64]{exemplarFloat64B}
+	t.Run("HistogramDataPointFloat64", testDatatypeIgnoreExemplars(histogramDataPointFloat64A, hdpFloat64, equalHistogramDataPoints[float64]))
+
+	dpInt64 := dataPointInt64A
+	dpInt64.Exemplars = []metricdata.Exemplar[int64]{exemplarInt64B}
+	t.Run("DataPointInt64", testDatatypeIgnoreExemplars(dataPointInt64A, dpInt64, equalDataPoints[int64]))
+
+	dpFloat64 := dataPointFloat64A
+	dpFloat64.Exemplars = []metricdata.Exemplar[float64]{exemplarFloat64B}
+	t.Run("DataPointFloat64", testDatatypeIgnoreExemplars(dataPointFloat64A, dpFloat64, equalDataPoints[float64]))
 }

 type unknownAggregation struct {
@@ -279,7 +423,8 @@ func TestAssertAggregationsEqual(t *testing.T) {
 	AssertAggregationsEqual(t, sumFloat64A, sumFloat64A)
 	AssertAggregationsEqual(t, gaugeInt64A, gaugeInt64A)
 	AssertAggregationsEqual(t, gaugeFloat64A, gaugeFloat64A)
-	AssertAggregationsEqual(t, histogramA, histogramA)
+	AssertAggregationsEqual(t, histogramInt64A, histogramInt64A)
+	AssertAggregationsEqual(t, histogramFloat64A, histogramFloat64A)

 	r := equalAggregations(sumInt64A, nil, config{})
 	assert.Len(t, r, 1, "should return nil comparison mismatch only")
@@ -291,46 +436,56 @@ func TestAssertAggregationsEqual(t *testing.T) {
 	assert.Len(t, r, 1, "should return with unknown aggregation only")

 	r = equalAggregations(sumInt64A, sumInt64B, config{})
-	assert.Greaterf(t, len(r), 0, "%v == %v", sumInt64A, sumInt64B)
+	assert.Greaterf(t, len(r), 0, "sums should not be equal: %v == %v", sumInt64A, sumInt64B)

 	r = equalAggregations(sumInt64A, sumInt64C, config{ignoreTimestamp: true})
-	assert.Equalf(t, len(r), 0, "%v == %v", sumInt64A, sumInt64C)
+	assert.Len(t, r, 0, "sums should be equal: %v", r)

 	r = equalAggregations(sumFloat64A, sumFloat64B, config{})
-	assert.Greaterf(t, len(r), 0, "%v == %v", sumFloat64A, sumFloat64B)
+	assert.Greaterf(t, len(r), 0, "sums should not be equal: %v == %v", sumFloat64A, sumFloat64B)

 	r = equalAggregations(sumFloat64A, sumFloat64C, config{ignoreTimestamp: true})
-	assert.Equalf(t, len(r), 0, "%v == %v", sumFloat64A, sumFloat64C)
+	assert.Len(t, r, 0, "sums should be equal: %v", r)

 	r = equalAggregations(gaugeInt64A, gaugeInt64B, config{})
-	assert.Greaterf(t, len(r), 0, "%v == %v", gaugeInt64A, gaugeInt64B)
+	assert.Greaterf(t, len(r), 0, "gauges should not be equal: %v == %v", gaugeInt64A, gaugeInt64B)

 	r = equalAggregations(gaugeInt64A, gaugeInt64C, config{ignoreTimestamp: true})
-	assert.Equalf(t, len(r), 0, "%v == %v", gaugeInt64A, gaugeInt64C)
+	assert.Len(t, r, 0, "gauges should be equal: %v", r)

 	r = equalAggregations(gaugeFloat64A, gaugeFloat64B, config{})
-	assert.Greaterf(t, len(r), 0, "%v == %v", gaugeFloat64A, gaugeFloat64B)
+	assert.Greaterf(t, len(r), 0, "gauges should not be equal: %v == %v", gaugeFloat64A, gaugeFloat64B)

 	r = equalAggregations(gaugeFloat64A, gaugeFloat64C, config{ignoreTimestamp: true})
-	assert.Equalf(t, len(r), 0, "%v == %v", gaugeFloat64A, gaugeFloat64C)
+	assert.Len(t, r, 0, "gauges should be equal: %v", r)

-	r = equalAggregations(histogramA, histogramB, config{})
-	assert.Greaterf(t, len(r), 0, "%v == %v", histogramA, histogramB)
+	r = equalAggregations(histogramInt64A, histogramInt64B, config{})
+	assert.Greaterf(t, len(r), 0, "histograms should not be equal: %v == %v", histogramInt64A, histogramInt64B)

-	r = equalAggregations(histogramA, histogramC, config{ignoreTimestamp: true})
-	assert.Equalf(t, len(r), 0, "%v == %v", histogramA, histogramC)
+	r = equalAggregations(histogramInt64A, histogramInt64C, config{ignoreTimestamp: true})
+	assert.Len(t, r, 0, "histograms should be equal: %v", r)
+
+	r = equalAggregations(histogramFloat64A, histogramFloat64B, config{})
+	assert.Greaterf(t, len(r), 0, "histograms should not be equal: %v == %v", histogramFloat64A, histogramFloat64B)
+
+	r = equalAggregations(histogramFloat64A, histogramFloat64C, config{ignoreTimestamp: true})
+	assert.Len(t, r, 0, "histograms should be equal: %v", r)
 }

 func TestAssertAttributes(t *testing.T) {
 	AssertHasAttributes(t, minA, attribute.Bool("A", true)) // No-op, always pass.
+	AssertHasAttributes(t, exemplarInt64A, attribute.Bool("filter A", true))
+	AssertHasAttributes(t, exemplarFloat64A, attribute.Bool("filter A", true))
 	AssertHasAttributes(t, dataPointInt64A, attribute.Bool("A", true))
 	AssertHasAttributes(t, dataPointFloat64A, attribute.Bool("A", true))
 	AssertHasAttributes(t, gaugeInt64A, attribute.Bool("A", true))
 	AssertHasAttributes(t, gaugeFloat64A, attribute.Bool("A", true))
 	AssertHasAttributes(t, sumInt64A, attribute.Bool("A", true))
 	AssertHasAttributes(t, sumFloat64A, attribute.Bool("A", true))
-	AssertHasAttributes(t, histogramDataPointA, attribute.Bool("A", true))
-	AssertHasAttributes(t, histogramA, attribute.Bool("A", true))
+	AssertHasAttributes(t, histogramDataPointInt64A, attribute.Bool("A", true))
+	AssertHasAttributes(t, histogramDataPointFloat64A, attribute.Bool("A", true))
+	AssertHasAttributes(t, histogramInt64A, attribute.Bool("A", true))
+	AssertHasAttributes(t, histogramFloat64A, attribute.Bool("A", true))
 	AssertHasAttributes(t, metricsA, attribute.Bool("A", true))
 	AssertHasAttributes(t, scopeMetricsA, attribute.Bool("A", true))
 	AssertHasAttributes(t, resourceMetricsA, attribute.Bool("A", true))
@@ -343,8 +498,10 @@ func TestAssertAttributes(t *testing.T) {
 	assert.Equal(t, len(r), 0, "sumInt64A has A=True")
 	r = hasAttributesAggregation(sumFloat64A, attribute.Bool("A", true))
 	assert.Equal(t, len(r), 0, "sumFloat64A has A=True")
-	r = hasAttributesAggregation(histogramA, attribute.Bool("A", true))
-	assert.Equal(t, len(r), 0, "histogramA has A=True")
+	r = hasAttributesAggregation(histogramInt64A, attribute.Bool("A", true))
+	assert.Equal(t, len(r), 0, "histogramInt64A has A=True")
+	r = hasAttributesAggregation(histogramFloat64A, attribute.Bool("A", true))
+	assert.Equal(t, len(r), 0, "histogramFloat64A has A=True")

 	r = hasAttributesAggregation(gaugeInt64A, attribute.Bool("A", false))
 	assert.Greater(t, len(r), 0, "gaugeInt64A does not have A=False")
@@ -354,8 +511,10 @@ func TestAssertAttributes(t *testing.T) {
 	assert.Greater(t, len(r), 0, "sumInt64A does not have A=False")
 	r = hasAttributesAggregation(sumFloat64A, attribute.Bool("A", false))
 	assert.Greater(t, len(r), 0, "sumFloat64A does not have A=False")
-	r = hasAttributesAggregation(histogramA, attribute.Bool("A", false))
-	assert.Greater(t, len(r), 0, "histogramA does not have A=False")
+	r = hasAttributesAggregation(histogramInt64A, attribute.Bool("A", false))
+	assert.Greater(t, len(r), 0, "histogramInt64A does not have A=False")
+	r = hasAttributesAggregation(histogramFloat64A, attribute.Bool("A", false))
+	assert.Greater(t, len(r), 0, "histogramFloat64A does not have A=False")

 	r = hasAttributesAggregation(gaugeInt64A, attribute.Bool("B", true))
 	assert.Greater(t, len(r), 0, "gaugeInt64A does not have Attribute B")
@@ -365,22 +524,26 @@ func TestAssertAttributes(t *testing.T) {
 	assert.Greater(t, len(r), 0, "sumInt64A does not have Attribute B")
 	r = hasAttributesAggregation(sumFloat64A, attribute.Bool("B", true))
 	assert.Greater(t, len(r), 0, "sumFloat64A does not have Attribute B")
-	r = hasAttributesAggregation(histogramA, attribute.Bool("B", true))
-	assert.Greater(t, len(r), 0, "histogramA does not have Attribute B")
+	r = hasAttributesAggregation(histogramInt64A, attribute.Bool("B", true))
+	assert.Greater(t, len(r), 0, "histogramIntA does not have Attribute B")
+	r = hasAttributesAggregation(histogramFloat64A, attribute.Bool("B", true))
+	assert.Greater(t, len(r), 0, "histogramFloatA does not have Attribute B")
 }

 func TestAssertAttributesFail(t *testing.T) {
 	fakeT := &testing.T{}
 	assert.False(t, AssertHasAttributes(fakeT, dataPointInt64A, attribute.Bool("A", false)))
 	assert.False(t, AssertHasAttributes(fakeT, dataPointFloat64A, attribute.Bool("B", true)))
+	assert.False(t, AssertHasAttributes(fakeT, exemplarInt64A, attribute.Bool("A", false)))
+	assert.False(t, AssertHasAttributes(fakeT, exemplarFloat64A, attribute.Bool("B", true)))
 	assert.False(t, AssertHasAttributes(fakeT, gaugeInt64A, attribute.Bool("A", false)))
 	assert.False(t, AssertHasAttributes(fakeT, gaugeFloat64A, attribute.Bool("B", true)))
 	assert.False(t, AssertHasAttributes(fakeT, sumInt64A, attribute.Bool("A", false)))
 	assert.False(t, AssertHasAttributes(fakeT, sumFloat64A, attribute.Bool("B", true)))
-	assert.False(t, AssertHasAttributes(fakeT, histogramDataPointA, attribute.Bool("A", false)))
-	assert.False(t, AssertHasAttributes(fakeT, histogramDataPointA, attribute.Bool("B", true)))
-	assert.False(t, AssertHasAttributes(fakeT, histogramA, attribute.Bool("A", false)))
-	assert.False(t, AssertHasAttributes(fakeT, histogramA, attribute.Bool("B", true)))
+	assert.False(t, AssertHasAttributes(fakeT, histogramDataPointInt64A, attribute.Bool("A", false)))
+	assert.False(t, AssertHasAttributes(fakeT, histogramDataPointFloat64A, attribute.Bool("B", true)))
+	assert.False(t, AssertHasAttributes(fakeT, histogramInt64A, attribute.Bool("A", false)))
+	assert.False(t, AssertHasAttributes(fakeT, histogramFloat64A, attribute.Bool("B", true)))
 	assert.False(t, AssertHasAttributes(fakeT, metricsA, attribute.Bool("A", false)))
 	assert.False(t, AssertHasAttributes(fakeT, metricsA, attribute.Bool("B", true)))
 	assert.False(t, AssertHasAttributes(fakeT, resourceMetricsA, attribute.Bool("A", false)))
--- a/sdk/metric/metricdata/metricdatatest/comparisons.go
+++ b/sdk/metric/metricdata/metricdatatest/comparisons.go
@@ -131,8 +131,14 @@ func equalAggregations(a, b metricdata.Aggregation, cfg config) (reasons []strin
 			reasons = append(reasons, "Sum[float64] not equal:")
 			reasons = append(reasons, r...)
 		}
-	case metricdata.Histogram:
-		r := equalHistograms(v, b.(metricdata.Histogram), cfg)
+	case metricdata.Histogram[int64]:
+		r := equalHistograms(v, b.(metricdata.Histogram[int64]), cfg)
+		if len(r) > 0 {
+			reasons = append(reasons, "Histogram not equal:")
+			reasons = append(reasons, r...)
+		}
+	case metricdata.Histogram[float64]:
+		r := equalHistograms(v, b.(metricdata.Histogram[float64]), cfg)
 		if len(r) > 0 {
 			reasons = append(reasons, "Histogram not equal:")
 			reasons = append(reasons, r...)
@@ -195,7 +201,7 @@ func equalSums[N int64 | float64](a, b metricdata.Sum[N], cfg config) (reasons [
 //
 // The DataPoints each Histogram contains are compared based on containing the
 // same HistogramDataPoint, not the order they are stored in.
-func equalHistograms(a, b metricdata.Histogram, cfg config) (reasons []string) {
+func equalHistograms[N int64 | float64](a, b metricdata.Histogram[N], cfg config) (reasons []string) {
 	if a.Temporality != b.Temporality {
 		reasons = append(reasons, notEqualStr("Temporality", a.Temporality, b.Temporality))
 	}
@@ -203,7 +209,7 @@ func equalHistograms(a, b metricdata.Histogram, cfg config) (reasons []string) {
 	r := compareDiff(diffSlices(
 		a.DataPoints,
 		b.DataPoints,
-		func(a, b metricdata.HistogramDataPoint) bool {
+		func(a, b metricdata.HistogramDataPoint[N]) bool {
 			r := equalHistogramDataPoints(a, b, cfg)
 			return len(r) == 0
 		},
@@ -237,12 +243,26 @@ func equalDataPoints[N int64 | float64](a, b metricdata.DataPoint[N], cfg config
 	if a.Value != b.Value {
 		reasons = append(reasons, notEqualStr("Value", a.Value, b.Value))
 	}
+
+	if !cfg.ignoreExemplars {
+		r := compareDiff(diffSlices(
+			a.Exemplars,
+			b.Exemplars,
+			func(a, b metricdata.Exemplar[N]) bool {
+				r := equalExemplars(a, b, cfg)
+				return len(r) == 0
+			},
+		))
+		if r != "" {
+			reasons = append(reasons, fmt.Sprintf("Exemplars not equal:\n%s", r))
+		}
+	}
 	return reasons
 }

 // equalHistogramDataPoints returns reasons HistogramDataPoints are not equal.
 // If they are equal, the returned reasons will be empty.
-func equalHistogramDataPoints(a, b metricdata.HistogramDataPoint, cfg config) (reasons []string) { // nolint: revive // Intentional internal control flag
+func equalHistogramDataPoints[N int64 | float64](a, b metricdata.HistogramDataPoint[N], cfg config) (reasons []string) { // nolint: revive // Intentional internal control flag
 	if !a.Attributes.Equals(&b.Attributes) {
 		reasons = append(reasons, notEqualStr(
 			"Attributes",
@@ -276,6 +296,19 @@ func equalHistogramDataPoints(a, b metricdata.HistogramDataPoint, cfg config) (r
 	if a.Sum != b.Sum {
 		reasons = append(reasons, notEqualStr("Sum", a.Sum, b.Sum))
 	}
+	if !cfg.ignoreExemplars {
+		r := compareDiff(diffSlices(
+			a.Exemplars,
+			b.Exemplars,
+			func(a, b metricdata.Exemplar[N]) bool {
+				r := equalExemplars(a, b, cfg)
+				return len(r) == 0
+			},
+		))
+		if r != "" {
+			reasons = append(reasons, fmt.Sprintf("Exemplars not equal:\n%s", r))
+		}
+	}
 	return reasons
 }

@@ -312,6 +345,82 @@ func eqExtrema(a, b metricdata.Extrema) bool {
 	return aV == bV
 }

+func equalKeyValue(a, b []attribute.KeyValue) bool {
+	// Comparison of []attribute.KeyValue as a comparable requires Go >= 1.20.
+	// To support Go < 1.20 use this function instead.
+	if len(a) != len(b) {
+		return false
+	}
+	for i, v := range a {
+		if v.Key != b[i].Key {
+			return false
+		}
+		if v.Value.Type() != b[i].Value.Type() {
+			return false
+		}
+		switch v.Value.Type() {
+		case attribute.BOOL:
+			if v.Value.AsBool() != b[i].Value.AsBool() {
+				return false
+			}
+		case attribute.INT64:
+			if v.Value.AsInt64() != b[i].Value.AsInt64() {
+				return false
+			}
+		case attribute.FLOAT64:
+			if v.Value.AsFloat64() != b[i].Value.AsFloat64() {
+				return false
+			}
+		case attribute.STRING:
+			if v.Value.AsString() != b[i].Value.AsString() {
+				return false
+			}
+		case attribute.BOOLSLICE:
+			if ok := equalSlices(v.Value.AsBoolSlice(), b[i].Value.AsBoolSlice()); !ok {
+				return false
+			}
+		case attribute.INT64SLICE:
+			if ok := equalSlices(v.Value.AsInt64Slice(), b[i].Value.AsInt64Slice()); !ok {
+				return false
+			}
+		case attribute.FLOAT64SLICE:
+			if ok := equalSlices(v.Value.AsFloat64Slice(), b[i].Value.AsFloat64Slice()); !ok {
+				return false
+			}
+		case attribute.STRINGSLICE:
+			if ok := equalSlices(v.Value.AsStringSlice(), b[i].Value.AsStringSlice()); !ok {
+				return false
+			}
+		default:
+			// We control all types passed to this, panic to signal developers
+			// early they changed things in an incompatible way.
+			panic(fmt.Sprintf("unknown attribute value type: %s", v.Value.Type()))
+		}
+	}
+	return true
+}
+
+func equalExemplars[N int64 | float64](a, b metricdata.Exemplar[N], cfg config) (reasons []string) {
+	if !equalKeyValue(a.FilteredAttributes, b.FilteredAttributes) {
+		reasons = append(reasons, notEqualStr("FilteredAttributes", a.FilteredAttributes, b.FilteredAttributes))
+	}
+	if !cfg.ignoreTimestamp {
+		if !a.Time.Equal(b.Time) {
+			reasons = append(reasons, notEqualStr("Time", a.Time.UnixNano(), b.Time.UnixNano()))
+		}
+	}
+	if a.Value != b.Value {
+		reasons = append(reasons, notEqualStr("Value", a.Value, b.Value))
+	}
+	if !equalSlices(a.SpanID, b.SpanID) {
+		reasons = append(reasons, notEqualStr("SpanID", a.SpanID, b.SpanID))
+	}
+	if !equalSlices(a.TraceID, b.TraceID) {
+		reasons = append(reasons, notEqualStr("TraceID", a.TraceID, b.TraceID))
+	}
+	return reasons
+}
+
 func diffSlices[T any](a, b []T, equal func(T, T) bool) (extraA, extraB []T) {
 	visited := make([]bool, len(b))
 	for i := 0; i < len(a); i++ {
@@ -372,6 +481,21 @@ func missingAttrStr(name string) string {
 	return fmt.Sprintf("missing attribute %s", name)
 }

+func hasAttributesExemplars[T int64 | float64](exemplar metricdata.Exemplar[T], attrs ...attribute.KeyValue) (reasons []string) {
+	s := attribute.NewSet(exemplar.FilteredAttributes...)
+	for _, attr := range attrs {
+		val, ok := s.Value(attr.Key)
+		if !ok {
+			reasons = append(reasons, missingAttrStr(string(attr.Key)))
+			continue
+		}
+		if val != attr.Value {
+			reasons = append(reasons, notEqualStr(string(attr.Key), attr.Value.Emit(), val.Emit()))
+		}
+	}
+	return reasons
+}
+
 func hasAttributesDataPoints[T int64 | float64](dp metricdata.DataPoint[T], attrs ...attribute.KeyValue) (reasons []string) {
 	for _, attr := range attrs {
 		val, ok := dp.Attributes.Value(attr.Key)
@@ -408,7 +532,7 @@ func hasAttributesSum[T int64 | float64](sum metricdata.Sum[T], attrs ...attribu
 	return reasons
 }

-func hasAttributesHistogramDataPoints(dp metricdata.HistogramDataPoint, attrs ...attribute.KeyValue) (reasons []string) {
+func hasAttributesHistogramDataPoints[T int64 | float64](dp metricdata.HistogramDataPoint[T], attrs ...attribute.KeyValue) (reasons []string) {
 	for _, attr := range attrs {
 		val, ok := dp.Attributes.Value(attr.Key)
 		if !ok {
@@ -422,7 +546,7 @@ func hasAttributesHistogramDataPoints(dp metricdata.HistogramDataPoint, attrs ..
 	return reasons
 }

-func hasAttributesHistogram(histogram metricdata.Histogram, attrs ...attribute.KeyValue) (reasons []string) {
+func hasAttributesHistogram[T int64 | float64](histogram metricdata.Histogram[T], attrs ...attribute.KeyValue) (reasons []string) {
 	for n, dp := range histogram.DataPoints {
 		reas := hasAttributesHistogramDataPoints(dp, attrs...)
 		if len(reas) > 0 {
@@ -443,7 +567,9 @@ func hasAttributesAggregation(agg metricdata.Aggregation, attrs ...attribute.Key
 		reasons = hasAttributesSum(agg, attrs...)
 	case metricdata.Sum[float64]:
 		reasons = hasAttributesSum(agg, attrs...)
-	case metricdata.Histogram:
+	case metricdata.Histogram[int64]:
+		reasons = hasAttributesHistogram(agg, attrs...)
+	case metricdata.Histogram[float64]:
 		reasons = hasAttributesHistogram(agg, attrs...)
 	default:
 		reasons = []string{fmt.Sprintf("unknown aggregation %T", agg)}