diff --git a/model/histogram/generic.go b/model/histogram/generic.go
index 8e941aa3c7..c62be0b08c 100644
--- a/model/histogram/generic.go
+++ b/model/histogram/generic.go
@@ -15,6 +15,7 @@ package histogram
 
 import (
 	"fmt"
+	"math"
 	"strings"
 )
 
@@ -325,3 +326,211 @@ func compactBuckets[IBC internalBucketCount](buckets []IBC, spans []Span, maxEmp
 
 	return buckets, spans
 }
+
+func getBound(idx, schema int32) float64 {
+	// Here a bit of context about the behavior for the last bucket counting
+	// regular numbers (called simply "last bucket" below) and the bucket
+	// counting observations of ±Inf (called "inf bucket" below, with an idx
+	// one higher than that of the "last bucket"):
+	//
+	// If we apply the usual formula to the last bucket, its upper bound
+	// would be calculated as +Inf. The reason is that the max possible
+	// regular float64 number (math.MaxFloat64) doesn't coincide with one of
+	// the calculated bucket boundaries. So the calculated boundary has to
+	// be larger than math.MaxFloat64, and the only float64 larger than
+	// math.MaxFloat64 is +Inf. However, we want to count actual
+	// observations of ±Inf in the inf bucket. Therefore, we have to treat
+	// the upper bound of the last bucket specially and set it to
+	// math.MaxFloat64. (The upper bound of the inf bucket, with its idx
+	// being one higher than that of the last bucket, naturally comes out as
+	// +Inf by the usual formula. So that's fine.)
+	//
+	// math.MaxFloat64 has a frac of 0.9999999999999999 and an exp of
+	// 1024. If there were a float64 number following math.MaxFloat64, it
+	// would have a frac of 1.0 and an exp of 1024, or equivalently a frac
+	// of 0.5 and an exp of 1025. However, since frac must be smaller than
+	// 1, and exp must be smaller than 1025, either representation overflows
+	// a float64. (Which, in turn, is the reason that math.MaxFloat64 is the
+	// largest possible float64. Q.E.D.) However, the formula for
+	// calculating the upper bound from the idx and schema of the last
+	// bucket results in precisely that. It is either frac=1.0 & exp=1024
+	// (for schema < 0) or frac=0.5 & exp=1025 (for schema >=0). (This is,
+	// by the way, a power of two where the exponent itself is a power of
+	// two, 2¹⁰ in fact, which coinicides with a bucket boundary in all
+	// schemas.) So these are the special cases we have to catch below.
+	if schema < 0 {
+		exp := int(idx) << -schema
+		if exp == 1024 {
+			// This is the last bucket before the overflow bucket
+			// (for ±Inf observations). Return math.MaxFloat64 as
+			// explained above.
+			return math.MaxFloat64
+		}
+		return math.Ldexp(1, exp)
+	}
+
+	fracIdx := idx & ((1 << schema) - 1)
+	frac := exponentialBounds[schema][fracIdx]
+	exp := (int(idx) >> schema) + 1
+	if frac == 0.5 && exp == 1025 {
+		// This is the last bucket before the overflow bucket (for ±Inf
+		// observations). Return math.MaxFloat64 as explained above.
+		return math.MaxFloat64
+	}
+	return math.Ldexp(frac, exp)
+}
+
+// exponentialBounds is a precalculated table of bucket bounds in the interval
+// [0.5,1) in schema 0 to 8.
+var exponentialBounds = [][]float64{
+	// Schema "0":
+	{0.5},
+	// Schema 1:
+	{0.5, 0.7071067811865475},
+	// Schema 2:
+	{0.5, 0.5946035575013605, 0.7071067811865475, 0.8408964152537144},
+	// Schema 3:
+	{
+		0.5, 0.5452538663326288, 0.5946035575013605, 0.6484197773255048,
+		0.7071067811865475, 0.7711054127039704, 0.8408964152537144, 0.9170040432046711,
+	},
+	// Schema 4:
+	{
+		0.5, 0.5221368912137069, 0.5452538663326288, 0.5693943173783458,
+		0.5946035575013605, 0.620928906036742, 0.6484197773255048, 0.6771277734684463,
+		0.7071067811865475, 0.7384130729697496, 0.7711054127039704, 0.805245165974627,
+		0.8408964152537144, 0.8781260801866495, 0.9170040432046711, 0.9576032806985735,
+	},
+	// Schema 5:
+	{
+		0.5, 0.5109485743270583, 0.5221368912137069, 0.5335702003384117,
+		0.5452538663326288, 0.5571933712979462, 0.5693943173783458, 0.5818624293887887,
+		0.5946035575013605, 0.6076236799902344, 0.620928906036742, 0.6345254785958666,
+		0.6484197773255048, 0.6626183215798706, 0.6771277734684463, 0.6919549409819159,
+		0.7071067811865475, 0.7225904034885232, 0.7384130729697496, 0.7545822137967112,
+		0.7711054127039704, 0.7879904225539431, 0.805245165974627, 0.8228777390769823,
+		0.8408964152537144, 0.8593096490612387, 0.8781260801866495, 0.8973545375015533,
+		0.9170040432046711, 0.9370838170551498, 0.9576032806985735, 0.9785720620876999,
+	},
+	// Schema 6:
+	{
+		0.5, 0.5054446430258502, 0.5109485743270583, 0.5165124395106142,
+		0.5221368912137069, 0.5278225891802786, 0.5335702003384117, 0.5393803988785598,
+		0.5452538663326288, 0.5511912916539204, 0.5571933712979462, 0.5632608093041209,
+		0.5693943173783458, 0.5755946149764913, 0.5818624293887887, 0.5881984958251406,
+		0.5946035575013605, 0.6010783657263515, 0.6076236799902344, 0.6142402680534349,
+		0.620928906036742, 0.6276903785123455, 0.6345254785958666, 0.6414350080393891,
+		0.6484197773255048, 0.6554806057623822, 0.6626183215798706, 0.6698337620266515,
+		0.6771277734684463, 0.6845012114872953, 0.6919549409819159, 0.6994898362691555,
+		0.7071067811865475, 0.7148066691959849, 0.7225904034885232, 0.7304588970903234,
+		0.7384130729697496, 0.7464538641456323, 0.7545822137967112, 0.762799075372269,
+		0.7711054127039704, 0.7795022001189185, 0.7879904225539431, 0.7965710756711334,
+		0.805245165974627, 0.8140137109286738, 0.8228777390769823, 0.8318382901633681,
+		0.8408964152537144, 0.8500531768592616, 0.8593096490612387, 0.8686669176368529,
+		0.8781260801866495, 0.8876882462632604, 0.8973545375015533, 0.9071260877501991,
+		0.9170040432046711, 0.9269895625416926, 0.9370838170551498, 0.9472879907934827,
+		0.9576032806985735, 0.9680308967461471, 0.9785720620876999, 0.9892280131939752,
+	},
+	// Schema 7:
+	{
+		0.5, 0.5027149505564014, 0.5054446430258502, 0.5081891574554764,
+		0.5109485743270583, 0.5137229745593818, 0.5165124395106142, 0.5193170509806894,
+		0.5221368912137069, 0.5249720429003435, 0.5278225891802786, 0.5306886136446309,
+		0.5335702003384117, 0.5364674337629877, 0.5393803988785598, 0.5423091811066545,
+		0.5452538663326288, 0.5482145409081883, 0.5511912916539204, 0.5541842058618393,
+		0.5571933712979462, 0.5602188762048033, 0.5632608093041209, 0.5663192597993595,
+		0.5693943173783458, 0.572486072215902, 0.5755946149764913, 0.5787200368168754,
+		0.5818624293887887, 0.585021884841625, 0.5881984958251406, 0.5913923554921704,
+		0.5946035575013605, 0.5978321960199137, 0.6010783657263515, 0.6043421618132907,
+		0.6076236799902344, 0.6109230164863786, 0.6142402680534349, 0.6175755319684665,
+		0.620928906036742, 0.6243004885946023, 0.6276903785123455, 0.6310986751971253,
+		0.6345254785958666, 0.637970889198196, 0.6414350080393891, 0.6449179367033329,
+		0.6484197773255048, 0.6519406325959679, 0.6554806057623822, 0.659039800633032,
+		0.6626183215798706, 0.6662162735415805, 0.6698337620266515, 0.6734708931164728,
+		0.6771277734684463, 0.6808045103191123, 0.6845012114872953, 0.688217985377265,
+		0.6919549409819159, 0.6957121878859629, 0.6994898362691555, 0.7032879969095076,
+		0.7071067811865475, 0.7109463010845827, 0.7148066691959849, 0.718687998724491,
+		0.7225904034885232, 0.7265139979245261, 0.7304588970903234, 0.7344252166684908,
+		0.7384130729697496, 0.7424225829363761, 0.7464538641456323, 0.7505070348132126,
+		0.7545822137967112, 0.7586795205991071, 0.762799075372269, 0.7669409989204777,
+		0.7711054127039704, 0.7752924388424999, 0.7795022001189185, 0.7837348199827764,
+		0.7879904225539431, 0.7922691326262467, 0.7965710756711334, 0.8008963778413465,
+		0.805245165974627, 0.8096175675974316, 0.8140137109286738, 0.8184337248834821,
+		0.8228777390769823, 0.8273458838280969, 0.8318382901633681, 0.8363550898207981,
+		0.8408964152537144, 0.8454623996346523, 0.8500531768592616, 0.8546688815502312,
+		0.8593096490612387, 0.8639756154809185, 0.8686669176368529, 0.8733836930995842,
+		0.8781260801866495, 0.8828942179666361, 0.8876882462632604, 0.8925083056594671,
+		0.8973545375015533, 0.9022270839033115, 0.9071260877501991, 0.9120516927035263,
+		0.9170040432046711, 0.9219832844793128, 0.9269895625416926, 0.9320230241988943,
+		0.9370838170551498, 0.9421720895161669, 0.9472879907934827, 0.9524316709088368,
+		0.9576032806985735, 0.9628029718180622, 0.9680308967461471, 0.9732872087896164,
+		0.9785720620876999, 0.9838856116165875, 0.9892280131939752, 0.9945994234836328,
+	},
+	// Schema 8:
+	{
+		0.5, 0.5013556375251013, 0.5027149505564014, 0.5040779490592088,
+		0.5054446430258502, 0.5068150424757447, 0.5081891574554764, 0.509566998038869,
+		0.5109485743270583, 0.5123338964485679, 0.5137229745593818, 0.5151158188430205,
+		0.5165124395106142, 0.5179128468009786, 0.5193170509806894, 0.520725062344158,
+		0.5221368912137069, 0.5235525479396449, 0.5249720429003435, 0.526395386502313,
+		0.5278225891802786, 0.5292536613972564, 0.5306886136446309, 0.5321274564422321,
+		0.5335702003384117, 0.5350168559101208, 0.5364674337629877, 0.5379219445313954,
+		0.5393803988785598, 0.5408428074966075, 0.5423091811066545, 0.5437795304588847,
+		0.5452538663326288, 0.5467321995364429, 0.5482145409081883, 0.549700901315111,
+		0.5511912916539204, 0.5526857228508706, 0.5541842058618393, 0.5556867516724088,
+		0.5571933712979462, 0.5587040757836845, 0.5602188762048033, 0.5617377836665098,
+		0.5632608093041209, 0.564787964283144, 0.5663192597993595, 0.5678547070789026,
+		0.5693943173783458, 0.5709381019847808, 0.572486072215902, 0.5740382394200894,
+		0.5755946149764913, 0.5771552102951081, 0.5787200368168754, 0.5802891060137493,
+		0.5818624293887887, 0.5834400184762408, 0.585021884841625, 0.5866080400818185,
+		0.5881984958251406, 0.5897932637314379, 0.5913923554921704, 0.5929957828304968,
+		0.5946035575013605, 0.5962156912915756, 0.5978321960199137, 0.5994530835371903,
+		0.6010783657263515, 0.6027080545025619, 0.6043421618132907, 0.6059806996384005,
+		0.6076236799902344, 0.6092711149137041, 0.6109230164863786, 0.6125793968185725,
+		0.6142402680534349, 0.6159056423670379, 0.6175755319684665, 0.6192499490999082,
+		0.620928906036742, 0.622612415087629, 0.6243004885946023, 0.6259931389331581,
+		0.6276903785123455, 0.6293922197748583, 0.6310986751971253, 0.6328097572894031,
+		0.6345254785958666, 0.6362458516947014, 0.637970889198196, 0.6397006037528346,
+		0.6414350080393891, 0.6431741147730128, 0.6449179367033329, 0.6466664866145447,
+		0.6484197773255048, 0.6501778216898253, 0.6519406325959679, 0.6537082229673385,
+		0.6554806057623822, 0.6572577939746774, 0.659039800633032, 0.6608266388015788,
+		0.6626183215798706, 0.6644148621029772, 0.6662162735415805, 0.6680225691020727,
+		0.6698337620266515, 0.6716498655934177, 0.6734708931164728, 0.6752968579460171,
+		0.6771277734684463, 0.6789636531064505, 0.6808045103191123, 0.6826503586020058,
+		0.6845012114872953, 0.6863570825438342, 0.688217985377265, 0.690083933630119,
+		0.6919549409819159, 0.6938310211492645, 0.6957121878859629, 0.6975984549830999,
+		0.6994898362691555, 0.7013863456101023, 0.7032879969095076, 0.7051948041086352,
+		0.7071067811865475, 0.7090239421602076, 0.7109463010845827, 0.7128738720527471,
+		0.7148066691959849, 0.7167447066838943, 0.718687998724491, 0.7206365595643126,
+		0.7225904034885232, 0.7245495448210174, 0.7265139979245261, 0.7284837772007218,
+		0.7304588970903234, 0.7324393720732029, 0.7344252166684908, 0.7364164454346837,
+		0.7384130729697496, 0.7404151139112358, 0.7424225829363761, 0.7444354947621984,
+		0.7464538641456323, 0.7484777058836176, 0.7505070348132126, 0.7525418658117031,
+		0.7545822137967112, 0.7566280937263048, 0.7586795205991071, 0.7607365094544071,
+		0.762799075372269, 0.7648672334736434, 0.7669409989204777, 0.7690203869158282,
+		0.7711054127039704, 0.7731960915705107, 0.7752924388424999, 0.7773944698885442,
+		0.7795022001189185, 0.7816156449856788, 0.7837348199827764, 0.7858597406461707,
+		0.7879904225539431, 0.7901268813264122, 0.7922691326262467, 0.7944171921585818,
+		0.7965710756711334, 0.7987307989543135, 0.8008963778413465, 0.8030678282083853,
+		0.805245165974627, 0.8074284071024302, 0.8096175675974316, 0.8118126635086642,
+		0.8140137109286738, 0.8162207259936375, 0.8184337248834821, 0.820652723822003,
+		0.8228777390769823, 0.8251087869603088, 0.8273458838280969, 0.8295890460808079,
+		0.8318382901633681, 0.8340936325652911, 0.8363550898207981, 0.8386226785089391,
+		0.8408964152537144, 0.8431763167241966, 0.8454623996346523, 0.8477546807446661,
+		0.8500531768592616, 0.8523579048290255, 0.8546688815502312, 0.8569861239649629,
+		0.8593096490612387, 0.8616394738731368, 0.8639756154809185, 0.8663180910111553,
+		0.8686669176368529, 0.871022112577578, 0.8733836930995842, 0.8757516765159389,
+		0.8781260801866495, 0.8805069215187917, 0.8828942179666361, 0.8852879870317771,
+		0.8876882462632604, 0.890095013257712, 0.8925083056594671, 0.8949281411607002,
+		0.8973545375015533, 0.8997875124702672, 0.9022270839033115, 0.9046732696855155,
+		0.9071260877501991, 0.909585556079304, 0.9120516927035263, 0.9145245157024483,
+		0.9170040432046711, 0.9194902933879467, 0.9219832844793128, 0.9244830347552253,
+		0.9269895625416926, 0.92950288621441, 0.9320230241988943, 0.9345499949706191,
+		0.9370838170551498, 0.93962450902828, 0.9421720895161669, 0.9447265771954693,
+		0.9472879907934827, 0.9498563490882775, 0.9524316709088368, 0.9550139751351947,
+		0.9576032806985735, 0.9601996065815236, 0.9628029718180622, 0.9654133954938133,
+		0.9680308967461471, 0.9706554947643201, 0.9732872087896164, 0.9759260581154889,
+		0.9785720620876999, 0.9812252401044634, 0.9838856116165875, 0.9865531961276168,
+		0.9892280131939752, 0.9919100824251095, 0.9945994234836328, 0.9972960560854698,
+	},
+}
diff --git a/model/histogram/generic_test.go b/model/histogram/generic_test.go
new file mode 100644
index 0000000000..55015c047f
--- /dev/null
+++ b/model/histogram/generic_test.go
@@ -0,0 +1,112 @@
+// Copyright 2022 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 histogram
+
+import (
+	"math"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetBound(t *testing.T) {
+	scenarios := []struct {
+		idx    int32
+		schema int32
+		want   float64
+	}{
+		{
+			idx:    -1,
+			schema: -1,
+			want:   0.25,
+		},
+		{
+			idx:    0,
+			schema: -1,
+			want:   1,
+		},
+		{
+			idx:    1,
+			schema: -1,
+			want:   4,
+		},
+		{
+			idx:    512,
+			schema: -1,
+			want:   math.MaxFloat64,
+		},
+		{
+			idx:    513,
+			schema: -1,
+			want:   math.Inf(+1),
+		},
+		{
+			idx:    -1,
+			schema: 0,
+			want:   0.5,
+		},
+		{
+			idx:    0,
+			schema: 0,
+			want:   1,
+		},
+		{
+			idx:    1,
+			schema: 0,
+			want:   2,
+		},
+		{
+			idx:    1024,
+			schema: 0,
+			want:   math.MaxFloat64,
+		},
+		{
+			idx:    1025,
+			schema: 0,
+			want:   math.Inf(+1),
+		},
+		{
+			idx:    -1,
+			schema: 2,
+			want:   0.8408964152537144,
+		},
+		{
+			idx:    0,
+			schema: 2,
+			want:   1,
+		},
+		{
+			idx:    1,
+			schema: 2,
+			want:   1.189207115002721,
+		},
+		{
+			idx:    4096,
+			schema: 2,
+			want:   math.MaxFloat64,
+		},
+		{
+			idx:    4097,
+			schema: 2,
+			want:   math.Inf(+1),
+		},
+	}
+
+	for _, s := range scenarios {
+		got := getBound(s.idx, s.schema)
+		if s.want != got {
+			require.Equal(t, s.want, got, "idx %d, schema %d", s.idx, s.schema)
+		}
+	}
+}
diff --git a/model/histogram/histogram.go b/model/histogram/histogram.go
index 03ea0af8d8..934c4dde9c 100644
--- a/model/histogram/histogram.go
+++ b/model/histogram/histogram.go
@@ -446,169 +446,3 @@ func (c *cumulativeBucketIterator) At() Bucket[uint64] {
 		Index:          c.currIdx - 1,
 	}
 }
-
-func getBound(idx, schema int32) float64 {
-	if schema < 0 {
-		return math.Ldexp(1, int(idx)<<(-schema))
-	}
-
-	fracIdx := idx & ((1 << schema) - 1)
-	frac := exponentialBounds[schema][fracIdx]
-	exp := (int(idx) >> schema) + 1
-	return math.Ldexp(frac, exp)
-}
-
-// exponentialBounds is a precalculated table of bucket bounds in the interval
-// [0.5,1) in schema 0 to 8.
-var exponentialBounds = [][]float64{
-	// Schema "0":
-	{0.5},
-	// Schema 1:
-	{0.5, 0.7071067811865475},
-	// Schema 2:
-	{0.5, 0.5946035575013605, 0.7071067811865475, 0.8408964152537144},
-	// Schema 3:
-	{
-		0.5, 0.5452538663326288, 0.5946035575013605, 0.6484197773255048,
-		0.7071067811865475, 0.7711054127039704, 0.8408964152537144, 0.9170040432046711,
-	},
-	// Schema 4:
-	{
-		0.5, 0.5221368912137069, 0.5452538663326288, 0.5693943173783458,
-		0.5946035575013605, 0.620928906036742, 0.6484197773255048, 0.6771277734684463,
-		0.7071067811865475, 0.7384130729697496, 0.7711054127039704, 0.805245165974627,
-		0.8408964152537144, 0.8781260801866495, 0.9170040432046711, 0.9576032806985735,
-	},
-	// Schema 5:
-	{
-		0.5, 0.5109485743270583, 0.5221368912137069, 0.5335702003384117,
-		0.5452538663326288, 0.5571933712979462, 0.5693943173783458, 0.5818624293887887,
-		0.5946035575013605, 0.6076236799902344, 0.620928906036742, 0.6345254785958666,
-		0.6484197773255048, 0.6626183215798706, 0.6771277734684463, 0.6919549409819159,
-		0.7071067811865475, 0.7225904034885232, 0.7384130729697496, 0.7545822137967112,
-		0.7711054127039704, 0.7879904225539431, 0.805245165974627, 0.8228777390769823,
-		0.8408964152537144, 0.8593096490612387, 0.8781260801866495, 0.8973545375015533,
-		0.9170040432046711, 0.9370838170551498, 0.9576032806985735, 0.9785720620876999,
-	},
-	// Schema 6:
-	{
-		0.5, 0.5054446430258502, 0.5109485743270583, 0.5165124395106142,
-		0.5221368912137069, 0.5278225891802786, 0.5335702003384117, 0.5393803988785598,
-		0.5452538663326288, 0.5511912916539204, 0.5571933712979462, 0.5632608093041209,
-		0.5693943173783458, 0.5755946149764913, 0.5818624293887887, 0.5881984958251406,
-		0.5946035575013605, 0.6010783657263515, 0.6076236799902344, 0.6142402680534349,
-		0.620928906036742, 0.6276903785123455, 0.6345254785958666, 0.6414350080393891,
-		0.6484197773255048, 0.6554806057623822, 0.6626183215798706, 0.6698337620266515,
-		0.6771277734684463, 0.6845012114872953, 0.6919549409819159, 0.6994898362691555,
-		0.7071067811865475, 0.7148066691959849, 0.7225904034885232, 0.7304588970903234,
-		0.7384130729697496, 0.7464538641456323, 0.7545822137967112, 0.762799075372269,
-		0.7711054127039704, 0.7795022001189185, 0.7879904225539431, 0.7965710756711334,
-		0.805245165974627, 0.8140137109286738, 0.8228777390769823, 0.8318382901633681,
-		0.8408964152537144, 0.8500531768592616, 0.8593096490612387, 0.8686669176368529,
-		0.8781260801866495, 0.8876882462632604, 0.8973545375015533, 0.9071260877501991,
-		0.9170040432046711, 0.9269895625416926, 0.9370838170551498, 0.9472879907934827,
-		0.9576032806985735, 0.9680308967461471, 0.9785720620876999, 0.9892280131939752,
-	},
-	// Schema 7:
-	{
-		0.5, 0.5027149505564014, 0.5054446430258502, 0.5081891574554764,
-		0.5109485743270583, 0.5137229745593818, 0.5165124395106142, 0.5193170509806894,
-		0.5221368912137069, 0.5249720429003435, 0.5278225891802786, 0.5306886136446309,
-		0.5335702003384117, 0.5364674337629877, 0.5393803988785598, 0.5423091811066545,
-		0.5452538663326288, 0.5482145409081883, 0.5511912916539204, 0.5541842058618393,
-		0.5571933712979462, 0.5602188762048033, 0.5632608093041209, 0.5663192597993595,
-		0.5693943173783458, 0.572486072215902, 0.5755946149764913, 0.5787200368168754,
-		0.5818624293887887, 0.585021884841625, 0.5881984958251406, 0.5913923554921704,
-		0.5946035575013605, 0.5978321960199137, 0.6010783657263515, 0.6043421618132907,
-		0.6076236799902344, 0.6109230164863786, 0.6142402680534349, 0.6175755319684665,
-		0.620928906036742, 0.6243004885946023, 0.6276903785123455, 0.6310986751971253,
-		0.6345254785958666, 0.637970889198196, 0.6414350080393891, 0.6449179367033329,
-		0.6484197773255048, 0.6519406325959679, 0.6554806057623822, 0.659039800633032,
-		0.6626183215798706, 0.6662162735415805, 0.6698337620266515, 0.6734708931164728,
-		0.6771277734684463, 0.6808045103191123, 0.6845012114872953, 0.688217985377265,
-		0.6919549409819159, 0.6957121878859629, 0.6994898362691555, 0.7032879969095076,
-		0.7071067811865475, 0.7109463010845827, 0.7148066691959849, 0.718687998724491,
-		0.7225904034885232, 0.7265139979245261, 0.7304588970903234, 0.7344252166684908,
-		0.7384130729697496, 0.7424225829363761, 0.7464538641456323, 0.7505070348132126,
-		0.7545822137967112, 0.7586795205991071, 0.762799075372269, 0.7669409989204777,
-		0.7711054127039704, 0.7752924388424999, 0.7795022001189185, 0.7837348199827764,
-		0.7879904225539431, 0.7922691326262467, 0.7965710756711334, 0.8008963778413465,
-		0.805245165974627, 0.8096175675974316, 0.8140137109286738, 0.8184337248834821,
-		0.8228777390769823, 0.8273458838280969, 0.8318382901633681, 0.8363550898207981,
-		0.8408964152537144, 0.8454623996346523, 0.8500531768592616, 0.8546688815502312,
-		0.8593096490612387, 0.8639756154809185, 0.8686669176368529, 0.8733836930995842,
-		0.8781260801866495, 0.8828942179666361, 0.8876882462632604, 0.8925083056594671,
-		0.8973545375015533, 0.9022270839033115, 0.9071260877501991, 0.9120516927035263,
-		0.9170040432046711, 0.9219832844793128, 0.9269895625416926, 0.9320230241988943,
-		0.9370838170551498, 0.9421720895161669, 0.9472879907934827, 0.9524316709088368,
-		0.9576032806985735, 0.9628029718180622, 0.9680308967461471, 0.9732872087896164,
-		0.9785720620876999, 0.9838856116165875, 0.9892280131939752, 0.9945994234836328,
-	},
-	// Schema 8:
-	{
-		0.5, 0.5013556375251013, 0.5027149505564014, 0.5040779490592088,
-		0.5054446430258502, 0.5068150424757447, 0.5081891574554764, 0.509566998038869,
-		0.5109485743270583, 0.5123338964485679, 0.5137229745593818, 0.5151158188430205,
-		0.5165124395106142, 0.5179128468009786, 0.5193170509806894, 0.520725062344158,
-		0.5221368912137069, 0.5235525479396449, 0.5249720429003435, 0.526395386502313,
-		0.5278225891802786, 0.5292536613972564, 0.5306886136446309, 0.5321274564422321,
-		0.5335702003384117, 0.5350168559101208, 0.5364674337629877, 0.5379219445313954,
-		0.5393803988785598, 0.5408428074966075, 0.5423091811066545, 0.5437795304588847,
-		0.5452538663326288, 0.5467321995364429, 0.5482145409081883, 0.549700901315111,
-		0.5511912916539204, 0.5526857228508706, 0.5541842058618393, 0.5556867516724088,
-		0.5571933712979462, 0.5587040757836845, 0.5602188762048033, 0.5617377836665098,
-		0.5632608093041209, 0.564787964283144, 0.5663192597993595, 0.5678547070789026,
-		0.5693943173783458, 0.5709381019847808, 0.572486072215902, 0.5740382394200894,
-		0.5755946149764913, 0.5771552102951081, 0.5787200368168754, 0.5802891060137493,
-		0.5818624293887887, 0.5834400184762408, 0.585021884841625, 0.5866080400818185,
-		0.5881984958251406, 0.5897932637314379, 0.5913923554921704, 0.5929957828304968,
-		0.5946035575013605, 0.5962156912915756, 0.5978321960199137, 0.5994530835371903,
-		0.6010783657263515, 0.6027080545025619, 0.6043421618132907, 0.6059806996384005,
-		0.6076236799902344, 0.6092711149137041, 0.6109230164863786, 0.6125793968185725,
-		0.6142402680534349, 0.6159056423670379, 0.6175755319684665, 0.6192499490999082,
-		0.620928906036742, 0.622612415087629, 0.6243004885946023, 0.6259931389331581,
-		0.6276903785123455, 0.6293922197748583, 0.6310986751971253, 0.6328097572894031,
-		0.6345254785958666, 0.6362458516947014, 0.637970889198196, 0.6397006037528346,
-		0.6414350080393891, 0.6431741147730128, 0.6449179367033329, 0.6466664866145447,
-		0.6484197773255048, 0.6501778216898253, 0.6519406325959679, 0.6537082229673385,
-		0.6554806057623822, 0.6572577939746774, 0.659039800633032, 0.6608266388015788,
-		0.6626183215798706, 0.6644148621029772, 0.6662162735415805, 0.6680225691020727,
-		0.6698337620266515, 0.6716498655934177, 0.6734708931164728, 0.6752968579460171,
-		0.6771277734684463, 0.6789636531064505, 0.6808045103191123, 0.6826503586020058,
-		0.6845012114872953, 0.6863570825438342, 0.688217985377265, 0.690083933630119,
-		0.6919549409819159, 0.6938310211492645, 0.6957121878859629, 0.6975984549830999,
-		0.6994898362691555, 0.7013863456101023, 0.7032879969095076, 0.7051948041086352,
-		0.7071067811865475, 0.7090239421602076, 0.7109463010845827, 0.7128738720527471,
-		0.7148066691959849, 0.7167447066838943, 0.718687998724491, 0.7206365595643126,
-		0.7225904034885232, 0.7245495448210174, 0.7265139979245261, 0.7284837772007218,
-		0.7304588970903234, 0.7324393720732029, 0.7344252166684908, 0.7364164454346837,
-		0.7384130729697496, 0.7404151139112358, 0.7424225829363761, 0.7444354947621984,
-		0.7464538641456323, 0.7484777058836176, 0.7505070348132126, 0.7525418658117031,
-		0.7545822137967112, 0.7566280937263048, 0.7586795205991071, 0.7607365094544071,
-		0.762799075372269, 0.7648672334736434, 0.7669409989204777, 0.7690203869158282,
-		0.7711054127039704, 0.7731960915705107, 0.7752924388424999, 0.7773944698885442,
-		0.7795022001189185, 0.7816156449856788, 0.7837348199827764, 0.7858597406461707,
-		0.7879904225539431, 0.7901268813264122, 0.7922691326262467, 0.7944171921585818,
-		0.7965710756711334, 0.7987307989543135, 0.8008963778413465, 0.8030678282083853,
-		0.805245165974627, 0.8074284071024302, 0.8096175675974316, 0.8118126635086642,
-		0.8140137109286738, 0.8162207259936375, 0.8184337248834821, 0.820652723822003,
-		0.8228777390769823, 0.8251087869603088, 0.8273458838280969, 0.8295890460808079,
-		0.8318382901633681, 0.8340936325652911, 0.8363550898207981, 0.8386226785089391,
-		0.8408964152537144, 0.8431763167241966, 0.8454623996346523, 0.8477546807446661,
-		0.8500531768592616, 0.8523579048290255, 0.8546688815502312, 0.8569861239649629,
-		0.8593096490612387, 0.8616394738731368, 0.8639756154809185, 0.8663180910111553,
-		0.8686669176368529, 0.871022112577578, 0.8733836930995842, 0.8757516765159389,
-		0.8781260801866495, 0.8805069215187917, 0.8828942179666361, 0.8852879870317771,
-		0.8876882462632604, 0.890095013257712, 0.8925083056594671, 0.8949281411607002,
-		0.8973545375015533, 0.8997875124702672, 0.9022270839033115, 0.9046732696855155,
-		0.9071260877501991, 0.909585556079304, 0.9120516927035263, 0.9145245157024483,
-		0.9170040432046711, 0.9194902933879467, 0.9219832844793128, 0.9244830347552253,
-		0.9269895625416926, 0.92950288621441, 0.9320230241988943, 0.9345499949706191,
-		0.9370838170551498, 0.93962450902828, 0.9421720895161669, 0.9447265771954693,
-		0.9472879907934827, 0.9498563490882775, 0.9524316709088368, 0.9550139751351947,
-		0.9576032806985735, 0.9601996065815236, 0.9628029718180622, 0.9654133954938133,
-		0.9680308967461471, 0.9706554947643201, 0.9732872087896164, 0.9759260581154889,
-		0.9785720620876999, 0.9812252401044634, 0.9838856116165875, 0.9865531961276168,
-		0.9892280131939752, 0.9919100824251095, 0.9945994234836328, 0.9972960560854698,
-	},
-}
diff --git a/promql/quantile.go b/promql/quantile.go
index dc5472e49a..1561a2ce88 100644
--- a/promql/quantile.go
+++ b/promql/quantile.go
@@ -185,9 +185,9 @@ func histogramQuantile(q float64, h *histogram.FloatHistogram) float64 {
 		count = h.Count
 	}
 	// We could have hit the highest bucket without even reaching the rank
-	// (observations not counted in any bucket are considered "overflow"
-	// observations above the highest bucket), in which case we simple
-	// return the upper limit of the highest explicit bucket.
+	// (this should only happen if the histogram contains observations of
+	// the value NaN), in which case we simply return the upper limit of the
+	// highest explicit bucket.
 	if count < rank {
 		return bucket.Upper
 	}