Refactor tsdbutil for tests/native histograms (#11948)

* Add float histograms to ChunkFromSamplesGeneric

Signed-off-by: Justin Lei <justin.lei@grafana.com>

* Add Generate*Samples functions to tsdbutil

Signed-off-by: Justin Lei <justin.lei@grafana.com>

* PR responses

Signed-off-by: Justin Lei <justin.lei@grafana.com>

---------

Signed-off-by: Justin Lei <justin.lei@grafana.com>

promql/engine_test.go

@@ -25,7 +25,7 @@ import (
 
 	"github.com/go-kit/log"
 
-	"github.com/prometheus/prometheus/util/stats"
+	"github.com/prometheus/prometheus/tsdb/tsdbutil"
 
 	"github.com/stretchr/testify/require"
 	"go.uber.org/goleak"
@@ -35,7 +35,7 @@ import (
 	"github.com/prometheus/prometheus/model/timestamp"
 	"github.com/prometheus/prometheus/promql/parser"
 	"github.com/prometheus/prometheus/storage"
-	"github.com/prometheus/prometheus/tsdb"
+	"github.com/prometheus/prometheus/util/stats"
 )
 
 func TestMain(m *testing.M) {
@@ -3136,7 +3136,7 @@ func TestNativeHistogramRate(t *testing.T) {
 	lbls := labels.FromStrings("__name__", seriesName)
 
 	app := test.Storage().Appender(context.TODO())
-	for i, h := range tsdb.GenerateTestHistograms(100) {
+	for i, h := range tsdbutil.GenerateTestHistograms(100) {
 		_, err := app.AppendHistogram(0, lbls, int64(i)*int64(15*time.Second/time.Millisecond), h, nil)
 		require.NoError(t, err)
 	}
@@ -3181,7 +3181,7 @@ func TestNativeFloatHistogramRate(t *testing.T) {
 	lbls := labels.FromStrings("__name__", seriesName)
 
 	app := test.Storage().Appender(context.TODO())
-	for i, fh := range tsdb.GenerateTestFloatHistograms(100) {
+	for i, fh := range tsdbutil.GenerateTestFloatHistograms(100) {
 		_, err := app.AppendHistogram(0, lbls, int64(i)*int64(15*time.Second/time.Millisecond), nil, fh)
 		require.NoError(t, err)
 	}

rules/manager_test.go

@@ -38,8 +38,8 @@ import (
 	"github.com/prometheus/prometheus/promql"
 	"github.com/prometheus/prometheus/promql/parser"
 	"github.com/prometheus/prometheus/storage"
-	"github.com/prometheus/prometheus/tsdb"
 	"github.com/prometheus/prometheus/tsdb/chunkenc"
+	"github.com/prometheus/prometheus/tsdb/tsdbutil"
 	"github.com/prometheus/prometheus/util/teststorage"
 )
 
@@ -1348,7 +1348,7 @@ func TestNativeHistogramsInRecordingRules(t *testing.T) {
 
 	// Add some histograms.
 	db := suite.TSDB()
-	hists := tsdb.GenerateTestHistograms(5)
+	hists := tsdbutil.GenerateTestHistograms(5)
 	ts := time.Now()
 	app := db.Appender(context.Background())
 	for i, h := range hists {

storage/merge_test.go

@@ -23,7 +23,6 @@ import (
 
 	"github.com/stretchr/testify/require"
 
-	"github.com/prometheus/prometheus/model/histogram"
 	"github.com/prometheus/prometheus/model/labels"
 	"github.com/prometheus/prometheus/tsdb/chunkenc"
 	"github.com/prometheus/prometheus/tsdb/tsdbutil"
@@ -387,18 +386,11 @@ func TestCompactingChunkSeriesMerger(t *testing.T) {
 
 	// histogramSample returns a histogram that is unique to the ts.
 	histogramSample := func(ts int64) sample {
-		idx := ts + 1
+		return sample{t: ts, h: tsdbutil.GenerateTestHistogram(int(ts + 1))}
-		return sample{t: ts, h: &histogram.Histogram{
+	}
-			Schema:          2,
+
-			ZeroThreshold:   0.001,
+	floatHistogramSample := func(ts int64) sample {
-			ZeroCount:       2 * uint64(idx),
+		return sample{t: ts, fh: tsdbutil.GenerateTestFloatHistogram(int(ts + 1))}
-			Count:           5 * uint64(idx),
-			Sum:             12.34 * float64(idx),
-			PositiveSpans:   []histogram.Span{{Offset: 1, Length: 2}, {Offset: 2, Length: 1}},
-			NegativeSpans:   []histogram.Span{{Offset: 2, Length: 1}, {Offset: 1, Length: 2}},
-			PositiveBuckets: []int64{1 * idx, -1 * idx, 3 * idx},
-			NegativeBuckets: []int64{1 * idx, 2 * idx, 3 * idx},
-		}}
 	}
 
 	for _, tc := range []struct {
@@ -529,6 +521,46 @@ func TestCompactingChunkSeriesMerger(t *testing.T) {
 				[]tsdbutil.Sample{histogramSample(15)},
 			),
 		},
+		{
+			name: "float histogram chunks overlapping",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{floatHistogramSample(0), floatHistogramSample(5)}, []tsdbutil.Sample{floatHistogramSample(10), floatHistogramSample(15)}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{floatHistogramSample(2), floatHistogramSample(20)}, []tsdbutil.Sample{floatHistogramSample(25), floatHistogramSample(30)}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{floatHistogramSample(18), floatHistogramSample(26)}, []tsdbutil.Sample{floatHistogramSample(31), floatHistogramSample(35)}),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"),
+				[]tsdbutil.Sample{floatHistogramSample(0), floatHistogramSample(2), floatHistogramSample(5), floatHistogramSample(10), floatHistogramSample(15), floatHistogramSample(18), floatHistogramSample(20), floatHistogramSample(25), floatHistogramSample(26), floatHistogramSample(30)},
+				[]tsdbutil.Sample{floatHistogramSample(31), floatHistogramSample(35)},
+			),
+		},
+		{
+			name: "float histogram chunks overlapping with float chunks",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{floatHistogramSample(0), floatHistogramSample(5)}, []tsdbutil.Sample{floatHistogramSample(10), floatHistogramSample(15)}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{1, 1, nil, nil}, sample{12, 12, nil, nil}}, []tsdbutil.Sample{sample{14, 14, nil, nil}}),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"),
+				[]tsdbutil.Sample{floatHistogramSample(0)},
+				[]tsdbutil.Sample{sample{1, 1, nil, nil}},
+				[]tsdbutil.Sample{floatHistogramSample(5), floatHistogramSample(10)},
+				[]tsdbutil.Sample{sample{12, 12, nil, nil}, sample{14, 14, nil, nil}},
+				[]tsdbutil.Sample{floatHistogramSample(15)},
+			),
+		},
+		{
+			name: "float histogram chunks overlapping with histogram chunks",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{floatHistogramSample(0), floatHistogramSample(5)}, []tsdbutil.Sample{floatHistogramSample(10), floatHistogramSample(15)}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{histogramSample(1), histogramSample(12)}, []tsdbutil.Sample{histogramSample(14)}),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"),
+				[]tsdbutil.Sample{floatHistogramSample(0)},
+				[]tsdbutil.Sample{histogramSample(1)},
+				[]tsdbutil.Sample{floatHistogramSample(5), floatHistogramSample(10)},
+				[]tsdbutil.Sample{histogramSample(12), histogramSample(14)},
+				[]tsdbutil.Sample{floatHistogramSample(15)},
+			),
+		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			merged := m(tc.input...)

tsdb/agent/db_test.go

@@ -54,10 +54,10 @@ func TestDB_InvalidSeries(t *testing.T) {
 	})
 
 	t.Run("Histograms", func(t *testing.T) {
-		_, err := app.AppendHistogram(0, labels.Labels{}, 0, tsdb.GenerateTestHistograms(1)[0], nil)
+		_, err := app.AppendHistogram(0, labels.Labels{}, 0, tsdbutil.GenerateTestHistograms(1)[0], nil)
 		require.ErrorIs(t, err, tsdb.ErrInvalidSample, "should reject empty labels")
 
-		_, err = app.AppendHistogram(0, labels.FromStrings("a", "1", "a", "2"), 0, tsdb.GenerateTestHistograms(1)[0], nil)
+		_, err = app.AppendHistogram(0, labels.FromStrings("a", "1", "a", "2"), 0, tsdbutil.GenerateTestHistograms(1)[0], nil)
 		require.ErrorIs(t, err, tsdb.ErrInvalidSample, "should reject duplicate labels")
 	})
 
@@ -151,7 +151,7 @@ func TestCommit(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		histograms := tsdb.GenerateTestHistograms(numHistograms)
+		histograms := tsdbutil.GenerateTestHistograms(numHistograms)
 
 		for i := 0; i < numHistograms; i++ {
 			_, err := app.AppendHistogram(0, lset, int64(i), histograms[i], nil)
@@ -163,7 +163,7 @@ func TestCommit(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		floatHistograms := tsdb.GenerateTestFloatHistograms(numHistograms)
+		floatHistograms := tsdbutil.GenerateTestFloatHistograms(numHistograms)
 
 		for i := 0; i < numHistograms; i++ {
 			_, err := app.AppendHistogram(0, lset, int64(i), nil, floatHistograms[i])
@@ -257,7 +257,7 @@ func TestRollback(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		histograms := tsdb.GenerateTestHistograms(numHistograms)
+		histograms := tsdbutil.GenerateTestHistograms(numHistograms)
 
 		for i := 0; i < numHistograms; i++ {
 			_, err := app.AppendHistogram(0, lset, int64(i), histograms[i], nil)
@@ -269,7 +269,7 @@ func TestRollback(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		floatHistograms := tsdb.GenerateTestFloatHistograms(numHistograms)
+		floatHistograms := tsdbutil.GenerateTestFloatHistograms(numHistograms)
 
 		for i := 0; i < numHistograms; i++ {
 			_, err := app.AppendHistogram(0, lset, int64(i), nil, floatHistograms[i])
@@ -374,7 +374,7 @@ func TestFullTruncateWAL(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		histograms := tsdb.GenerateTestHistograms(numHistograms)
+		histograms := tsdbutil.GenerateTestHistograms(numHistograms)
 
 		for i := 0; i < numHistograms; i++ {
 			_, err := app.AppendHistogram(0, lset, int64(lastTs), histograms[i], nil)
@@ -387,7 +387,7 @@ func TestFullTruncateWAL(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		floatHistograms := tsdb.GenerateTestFloatHistograms(numHistograms)
+		floatHistograms := tsdbutil.GenerateTestFloatHistograms(numHistograms)
 
 		for i := 0; i < numHistograms; i++ {
 			_, err := app.AppendHistogram(0, lset, int64(lastTs), nil, floatHistograms[i])
@@ -436,7 +436,7 @@ func TestPartialTruncateWAL(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		histograms := tsdb.GenerateTestHistograms(numDatapoints)
+		histograms := tsdbutil.GenerateTestHistograms(numDatapoints)
 
 		for i := 0; i < numDatapoints; i++ {
 			_, err := app.AppendHistogram(0, lset, lastTs, histograms[i], nil)
@@ -449,7 +449,7 @@ func TestPartialTruncateWAL(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		floatHistograms := tsdb.GenerateTestFloatHistograms(numDatapoints)
+		floatHistograms := tsdbutil.GenerateTestFloatHistograms(numDatapoints)
 
 		for i := 0; i < numDatapoints; i++ {
 			_, err := app.AppendHistogram(0, lset, lastTs, nil, floatHistograms[i])
@@ -475,7 +475,7 @@ func TestPartialTruncateWAL(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		histograms := tsdb.GenerateTestHistograms(numDatapoints)
+		histograms := tsdbutil.GenerateTestHistograms(numDatapoints)
 
 		for i := 0; i < numDatapoints; i++ {
 			_, err := app.AppendHistogram(0, lset, lastTs, histograms[i], nil)
@@ -488,7 +488,7 @@ func TestPartialTruncateWAL(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		floatHistograms := tsdb.GenerateTestFloatHistograms(numDatapoints)
+		floatHistograms := tsdbutil.GenerateTestFloatHistograms(numDatapoints)
 
 		for i := 0; i < numDatapoints; i++ {
 			_, err := app.AppendHistogram(0, lset, lastTs, nil, floatHistograms[i])
@@ -529,7 +529,7 @@ func TestWALReplay(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		histograms := tsdb.GenerateTestHistograms(numHistograms)
+		histograms := tsdbutil.GenerateTestHistograms(numHistograms)
 
 		for i := 0; i < numHistograms; i++ {
 			_, err := app.AppendHistogram(0, lset, lastTs, histograms[i], nil)
@@ -541,7 +541,7 @@ func TestWALReplay(t *testing.T) {
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
-		floatHistograms := tsdb.GenerateTestFloatHistograms(numHistograms)
+		floatHistograms := tsdbutil.GenerateTestFloatHistograms(numHistograms)
 
 		for i := 0; i < numHistograms; i++ {
 			_, err := app.AppendHistogram(0, lset, lastTs, nil, floatHistograms[i])
@@ -622,7 +622,7 @@ func Test_ExistingWAL_NextRef(t *testing.T) {
 	}
 
 	histogramCount := 10
-	histograms := tsdb.GenerateTestHistograms(histogramCount)
+	histograms := tsdbutil.GenerateTestHistograms(histogramCount)
 	// Append <histogramCount> series
 	for i := 0; i < histogramCount; i++ {
 		lset := labels.FromStrings(model.MetricNameLabel, fmt.Sprintf("histogram_%d", i))

tsdb/head.go

@@ -17,7 +17,6 @@ import (
 	"fmt"
 	"io"
 	"math"
-	"math/rand"
 	"path/filepath"
 	"sync"
 	"time"
@@ -2037,93 +2036,3 @@ func (h *Head) updateWALReplayStatusRead(current int) {
 
 	h.stats.WALReplayStatus.Current = current
 }
-
-func GenerateTestHistograms(n int) (r []*histogram.Histogram) {
-	for i := 0; i < n; i++ {
-		h := GenerateTestHistogram(i)
-		if i > 0 {
-			h.CounterResetHint = histogram.NotCounterReset
-		}
-		r = append(r, h)
-	}
-	return r
-}
-
-// Generates a test histogram, it is up to the user to set any known counter reset hint.
-func GenerateTestHistogram(i int) *histogram.Histogram {
-	return &histogram.Histogram{
-		Count:         10 + uint64(i*8),
-		ZeroCount:     2 + uint64(i),
-		ZeroThreshold: 0.001,
-		Sum:           18.4 * float64(i+1),
-		Schema:        1,
-		PositiveSpans: []histogram.Span{
-			{Offset: 0, Length: 2},
-			{Offset: 1, Length: 2},
-		},
-		PositiveBuckets: []int64{int64(i + 1), 1, -1, 0},
-		NegativeSpans: []histogram.Span{
-			{Offset: 0, Length: 2},
-			{Offset: 1, Length: 2},
-		},
-		NegativeBuckets: []int64{int64(i + 1), 1, -1, 0},
-	}
-}
-
-func GenerateTestGaugeHistograms(n int) (r []*histogram.Histogram) {
-	for x := 0; x < n; x++ {
-		r = append(r, GenerateTestGaugeHistogram(rand.Intn(n)))
-	}
-	return r
-}
-
-func GenerateTestGaugeHistogram(i int) *histogram.Histogram {
-	h := GenerateTestHistogram(i)
-	h.CounterResetHint = histogram.GaugeType
-	return h
-}
-
-func GenerateTestFloatHistograms(n int) (r []*histogram.FloatHistogram) {
-	for i := 0; i < n; i++ {
-		h := GenerateTestFloatHistogram(i)
-		if i > 0 {
-			h.CounterResetHint = histogram.NotCounterReset
-		}
-		r = append(r, h)
-	}
-	return r
-}
-
-// Generates a test float histogram, it is up to the user to set any known counter reset hint.
-func GenerateTestFloatHistogram(i int) *histogram.FloatHistogram {
-	return &histogram.FloatHistogram{
-		Count:         10 + float64(i*8),
-		ZeroCount:     2 + float64(i),
-		ZeroThreshold: 0.001,
-		Sum:           18.4 * float64(i+1),
-		Schema:        1,
-		PositiveSpans: []histogram.Span{
-			{Offset: 0, Length: 2},
-			{Offset: 1, Length: 2},
-		},
-		PositiveBuckets: []float64{float64(i + 1), float64(i + 2), float64(i + 1), float64(i + 1)},
-		NegativeSpans: []histogram.Span{
-			{Offset: 0, Length: 2},
-			{Offset: 1, Length: 2},
-		},
-		NegativeBuckets: []float64{float64(i + 1), float64(i + 2), float64(i + 1), float64(i + 1)},
-	}
-}
-
-func GenerateTestGaugeFloatHistograms(n int) (r []*histogram.FloatHistogram) {
-	for x := 0; x < n; x++ {
-		r = append(r, GenerateTestGaugeFloatHistogram(rand.Intn(n)))
-	}
-	return r
-}
-
-func GenerateTestGaugeFloatHistogram(i int) *histogram.FloatHistogram {
-	h := GenerateTestFloatHistogram(i)
-	h.CounterResetHint = histogram.GaugeType
-	return h
-}

tsdb/head_test.go

@@ -1343,7 +1343,7 @@ func TestMemSeries_appendHistogram(t *testing.T) {
 
 	s := newMemSeries(labels.Labels{}, 1, defaultIsolationDisabled)
 
-	histograms := GenerateTestHistograms(4)
+	histograms := tsdbutil.GenerateTestHistograms(4)
 	histogramWithOneMoreBucket := histograms[3].Copy()
 	histogramWithOneMoreBucket.Count++
 	histogramWithOneMoreBucket.Sum += 1.23
@@ -2836,7 +2836,7 @@ func TestAppendHistogram(t *testing.T) {
 			expHistograms := make([]tsdbutil.Sample, 0, 2*numHistograms)
 
 			// Counter integer histograms.
-			for _, h := range GenerateTestHistograms(numHistograms) {
+			for _, h := range tsdbutil.GenerateTestHistograms(numHistograms) {
 				_, err := app.AppendHistogram(0, l, ingestTs, h, nil)
 				require.NoError(t, err)
 				expHistograms = append(expHistograms, sample{t: ingestTs, h: h})
@@ -2848,7 +2848,7 @@ func TestAppendHistogram(t *testing.T) {
 			}
 
 			// Gauge integer histograms.
-			for _, h := range GenerateTestGaugeHistograms(numHistograms) {
+			for _, h := range tsdbutil.GenerateTestGaugeHistograms(numHistograms) {
 				_, err := app.AppendHistogram(0, l, ingestTs, h, nil)
 				require.NoError(t, err)
 				expHistograms = append(expHistograms, sample{t: ingestTs, h: h})
@@ -2862,7 +2862,7 @@ func TestAppendHistogram(t *testing.T) {
 			expFloatHistograms := make([]tsdbutil.Sample, 0, 2*numHistograms)
 
 			// Counter float histograms.
-			for _, fh := range GenerateTestFloatHistograms(numHistograms) {
+			for _, fh := range tsdbutil.GenerateTestFloatHistograms(numHistograms) {
 				_, err := app.AppendHistogram(0, l, ingestTs, nil, fh)
 				require.NoError(t, err)
 				expFloatHistograms = append(expFloatHistograms, sample{t: ingestTs, fh: fh})
@@ -2874,7 +2874,7 @@ func TestAppendHistogram(t *testing.T) {
 			}
 
 			// Gauge float histograms.
-			for _, fh := range GenerateTestGaugeFloatHistograms(numHistograms) {
+			for _, fh := range tsdbutil.GenerateTestGaugeFloatHistograms(numHistograms) {
 				_, err := app.AppendHistogram(0, l, ingestTs, nil, fh)
 				require.NoError(t, err)
 				expFloatHistograms = append(expFloatHistograms, sample{t: ingestTs, fh: fh})
@@ -2944,9 +2944,9 @@ func TestHistogramInWALAndMmapChunk(t *testing.T) {
 		app = head.Appender(context.Background())
 		var hists []*histogram.Histogram
 		if gauge {
-			hists = GenerateTestGaugeHistograms(numHistograms)
+			hists = tsdbutil.GenerateTestGaugeHistograms(numHistograms)
 		} else {
-			hists = GenerateTestHistograms(numHistograms)
+			hists = tsdbutil.GenerateTestHistograms(numHistograms)
 		}
 		for _, h := range hists {
 			h.Count = h.Count * 2
@@ -2967,9 +2967,9 @@ func TestHistogramInWALAndMmapChunk(t *testing.T) {
 		app = head.Appender(context.Background())
 		var hists []*histogram.FloatHistogram
 		if gauge {
-			hists = GenerateTestGaugeFloatHistograms(numHistograms)
+			hists = tsdbutil.GenerateTestGaugeFloatHistograms(numHistograms)
 		} else {
-			hists = GenerateTestFloatHistograms(numHistograms)
+			hists = tsdbutil.GenerateTestFloatHistograms(numHistograms)
 		}
 		for _, h := range hists {
 			h.Count = h.Count * 2
@@ -3007,9 +3007,9 @@ func TestHistogramInWALAndMmapChunk(t *testing.T) {
 		app = head.Appender(context.Background())
 		var hists []*histogram.Histogram
 		if gauge {
-			hists = GenerateTestGaugeHistograms(100)
+			hists = tsdbutil.GenerateTestGaugeHistograms(100)
 		} else {
-			hists = GenerateTestHistograms(100)
+			hists = tsdbutil.GenerateTestHistograms(100)
 		}
 		for _, h := range hists {
 			ts++
@@ -3044,9 +3044,9 @@ func TestHistogramInWALAndMmapChunk(t *testing.T) {
 		app = head.Appender(context.Background())
 		var hists []*histogram.FloatHistogram
 		if gauge {
-			hists = GenerateTestGaugeFloatHistograms(100)
+			hists = tsdbutil.GenerateTestGaugeFloatHistograms(100)
 		} else {
-			hists = GenerateTestFloatHistograms(100)
+			hists = tsdbutil.GenerateTestFloatHistograms(100)
 		}
 		for _, h := range hists {
 			ts++
@@ -3422,14 +3422,14 @@ func TestHistogramMetrics(t *testing.T) {
 	for x := 0; x < 5; x++ {
 		expHSeries++
 		l := labels.FromStrings("a", fmt.Sprintf("b%d", x))
-		for i, h := range GenerateTestHistograms(numHistograms) {
+		for i, h := range tsdbutil.GenerateTestHistograms(numHistograms) {
 			app := head.Appender(context.Background())
 			_, err := app.AppendHistogram(0, l, int64(i), h, nil)
 			require.NoError(t, err)
 			require.NoError(t, app.Commit())
 			expHSamples++
 		}
-		for i, fh := range GenerateTestFloatHistograms(numHistograms) {
+		for i, fh := range tsdbutil.GenerateTestFloatHistograms(numHistograms) {
 			app := head.Appender(context.Background())
 			_, err := app.AppendHistogram(0, l, int64(numHistograms+i), nil, fh)
 			require.NoError(t, err)
@@ -3544,7 +3544,7 @@ func testHistogramStaleSampleHelper(t *testing.T, floatHistogram bool) {
 
 	// Adding stale in the same appender.
 	app := head.Appender(context.Background())
-	for _, h := range GenerateTestHistograms(numHistograms) {
+	for _, h := range tsdbutil.GenerateTestHistograms(numHistograms) {
 		var err error
 		if floatHistogram {
 			_, err = app.AppendHistogram(0, l, 100*int64(len(expHistograms)), nil, h.ToFloat())
@@ -3573,7 +3573,7 @@ func testHistogramStaleSampleHelper(t *testing.T, floatHistogram bool) {
 
 	// Adding stale in different appender and continuing series after a stale sample.
 	app = head.Appender(context.Background())
-	for _, h := range GenerateTestHistograms(2 * numHistograms)[numHistograms:] {
+	for _, h := range tsdbutil.GenerateTestHistograms(2 * numHistograms)[numHistograms:] {
 		var err error
 		if floatHistogram {
 			_, err = app.AppendHistogram(0, l, 100*int64(len(expHistograms)), nil, h.ToFloat())
@@ -3652,7 +3652,7 @@ func TestHistogramCounterResetHeader(t *testing.T) {
 				}
 			}
 
-			h := GenerateTestHistograms(1)[0]
+			h := tsdbutil.GenerateTestHistograms(1)[0]
 			h.PositiveBuckets = []int64{100, 1, 1, 1}
 			h.NegativeBuckets = []int64{100, 1, 1, 1}
 			h.Count = 1000
@@ -3729,8 +3729,8 @@ func TestAppendingDifferentEncodingToSameSeries(t *testing.T) {
 	})
 	db.DisableCompactions()
 
-	hists := GenerateTestHistograms(10)
+	hists := tsdbutil.GenerateTestHistograms(10)
-	floatHists := GenerateTestFloatHistograms(10)
+	floatHists := tsdbutil.GenerateTestFloatHistograms(10)
 	lbls := labels.FromStrings("a", "b")
 
 	var expResult []tsdbutil.Sample
@@ -4358,7 +4358,7 @@ func TestHistogramValidation(t *testing.T) {
 		errMsgFloat string // To be considered for float histogram only if it is non-empty.
 	}{
 		"valid histogram": {
-			h: GenerateTestHistograms(1)[0],
+			h: tsdbutil.GenerateTestHistograms(1)[0],
 		},
 		"rejects histogram who has too few negative buckets": {
 			h: &histogram.Histogram{
@@ -4641,7 +4641,7 @@ func TestGaugeHistogramWALAndChunkHeader(t *testing.T) {
 		require.NoError(t, app.Commit())
 	}
 
-	hists := GenerateTestGaugeHistograms(5)
+	hists := tsdbutil.GenerateTestGaugeHistograms(5)
 	hists[0].CounterResetHint = histogram.UnknownCounterReset
 	appendHistogram(hists[0])
 	appendHistogram(hists[1])
@@ -4716,7 +4716,7 @@ func TestGaugeFloatHistogramWALAndChunkHeader(t *testing.T) {
 		require.NoError(t, app.Commit())
 	}
 
-	hists := GenerateTestGaugeFloatHistograms(5)
+	hists := tsdbutil.GenerateTestGaugeFloatHistograms(5)
 	hists[0].CounterResetHint = histogram.UnknownCounterReset
 	appendHistogram(hists[0])
 	appendHistogram(hists[1])

tsdb/tsdbutil/chunks.go

@@ -72,6 +72,8 @@ func ChunkFromSamplesGeneric(s Samples) chunks.Meta {
 			ca.Append(s.Get(i).T(), s.Get(i).V())
 		case chunkenc.ValHistogram:
 			ca.AppendHistogram(s.Get(i).T(), s.Get(i).H())
+		case chunkenc.ValFloatHistogram:
+			ca.AppendFloatHistogram(s.Get(i).T(), s.Get(i).FH())
 		default:
 			panic(fmt.Sprintf("unknown sample type %s", sampleType.String()))
 		}
@@ -128,12 +130,18 @@ func PopulatedChunk(numSamples int, minTime int64) chunks.Meta {
 
 // GenerateSamples starting at start and counting up numSamples.
 func GenerateSamples(start, numSamples int) []Sample {
-	samples := make([]Sample, 0, numSamples)
+	return generateSamples(start, numSamples, func(i int) Sample {
-	for i := start; i < start+numSamples; i++ {
+		return sample{
-		samples = append(samples, sample{
 			t: int64(i),
 			v: float64(i),
-		})
+		}
+	})
+}
+
+func generateSamples(start, numSamples int, gen func(int) Sample) []Sample {
+	samples := make([]Sample, 0, numSamples)
+	for i := start; i < start+numSamples; i++ {
+		samples = append(samples, gen(i))
 	}
 	return samples
 }

tsdb/tsdbutil/histogram.go

@@ -0,0 +1,110 @@
+// Copyright 2023 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tsdbutil
+
+import (
+	"math/rand"
+
+	"github.com/prometheus/prometheus/model/histogram"
+)
+
+func GenerateTestHistograms(n int) (r []*histogram.Histogram) {
+	for i := 0; i < n; i++ {
+		h := GenerateTestHistogram(i)
+		if i > 0 {
+			h.CounterResetHint = histogram.NotCounterReset
+		}
+		r = append(r, h)
+	}
+	return r
+}
+
+// GenerateTestHistogram but it is up to the user to set any known counter reset hint.
+func GenerateTestHistogram(i int) *histogram.Histogram {
+	return &histogram.Histogram{
+		Count:         10 + uint64(i*8),
+		ZeroCount:     2 + uint64(i),
+		ZeroThreshold: 0.001,
+		Sum:           18.4 * float64(i+1),
+		Schema:        1,
+		PositiveSpans: []histogram.Span{
+			{Offset: 0, Length: 2},
+			{Offset: 1, Length: 2},
+		},
+		PositiveBuckets: []int64{int64(i + 1), 1, -1, 0},
+		NegativeSpans: []histogram.Span{
+			{Offset: 0, Length: 2},
+			{Offset: 1, Length: 2},
+		},
+		NegativeBuckets: []int64{int64(i + 1), 1, -1, 0},
+	}
+}
+
+func GenerateTestGaugeHistograms(n int) (r []*histogram.Histogram) {
+	for x := 0; x < n; x++ {
+		r = append(r, GenerateTestGaugeHistogram(rand.Intn(n)))
+	}
+	return r
+}
+
+func GenerateTestGaugeHistogram(i int) *histogram.Histogram {
+	h := GenerateTestHistogram(i)
+	h.CounterResetHint = histogram.GaugeType
+	return h
+}
+
+func GenerateTestFloatHistograms(n int) (r []*histogram.FloatHistogram) {
+	for i := 0; i < n; i++ {
+		h := GenerateTestFloatHistogram(i)
+		if i > 0 {
+			h.CounterResetHint = histogram.NotCounterReset
+		}
+		r = append(r, h)
+	}
+	return r
+}
+
+// GenerateTestFloatHistogram but it is up to the user to set any known counter reset hint.
+func GenerateTestFloatHistogram(i int) *histogram.FloatHistogram {
+	return &histogram.FloatHistogram{
+		Count:         10 + float64(i*8),
+		ZeroCount:     2 + float64(i),
+		ZeroThreshold: 0.001,
+		Sum:           18.4 * float64(i+1),
+		Schema:        1,
+		PositiveSpans: []histogram.Span{
+			{Offset: 0, Length: 2},
+			{Offset: 1, Length: 2},
+		},
+		PositiveBuckets: []float64{float64(i + 1), float64(i + 2), float64(i + 1), float64(i + 1)},
+		NegativeSpans: []histogram.Span{
+			{Offset: 0, Length: 2},
+			{Offset: 1, Length: 2},
+		},
+		NegativeBuckets: []float64{float64(i + 1), float64(i + 2), float64(i + 1), float64(i + 1)},
+	}
+}
+
+func GenerateTestGaugeFloatHistograms(n int) (r []*histogram.FloatHistogram) {
+	for x := 0; x < n; x++ {
+		r = append(r, GenerateTestGaugeFloatHistogram(rand.Intn(n)))
+	}
+	return r
+}
+
+func GenerateTestGaugeFloatHistogram(i int) *histogram.FloatHistogram {
+	h := GenerateTestFloatHistogram(i)
+	h.CounterResetHint = histogram.GaugeType
+	return h
+}