apitech
/
prometheus
mirror of https://github.com/prometheus/prometheus
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Change Validate to be a method on histogram structs

Browse Source 
Signed-off-by: Linas Medziunas <linas.medziunas@gmail.com>
pull/12977/head
Linas Medziunas 2 years ago
parent 1f8aea11d6
commit ebed7d0612
8 changed files with 288 additions and 315 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 27
      model/histogram/float_histogram.go
  2. 56
      model/histogram/generic.go
  3. 45
      model/histogram/histogram.go
  4. 156
      model/histogram/histogram_test.go
  5. 136
      model/histogram/validate.go
  6. 175
      model/histogram/validate_test.go
  7. 4
      tsdb/agent/db.go
  8. 4
      tsdb/head_append.go

27
model/histogram/float_histogram.go
Unescape View File

@ -17,6 +17,8 @@ import (
"fmt"
"math"
"strings"
"github.com/pkg/errors"
)
// FloatHistogram is similar to Histogram but uses float64 for all
@ -593,6 +595,31 @@ func (h *FloatHistogram) AllReverseBucketIterator() BucketIterator[float64] {
}
}
// Validate validates consistency between span and bucket slices. Also, buckets are checked
// against negative values.
// We do not check for h.Count being at least as large as the sum of the
// counts in the buckets because floating point precision issues can
// create false positives here.
func (h *FloatHistogram) Validate() error {
if err := checkHistogramSpans(h.NegativeSpans, len(h.NegativeBuckets)); err != nil {
return errors.Wrap(err, "negative side")
}
if err := checkHistogramSpans(h.PositiveSpans, len(h.PositiveBuckets)); err != nil {
return errors.Wrap(err, "positive side")
}
var nCount, pCount float64
err := checkHistogramBuckets(h.NegativeBuckets, &nCount, false)
if err != nil {
return errors.Wrap(err, "negative side")
}
err = checkHistogramBuckets(h.PositiveBuckets, &pCount, false)
if err != nil {
return errors.Wrap(err, "positive side")
}
return nil
}
// zeroCountForLargerThreshold returns what the histogram's zero count would be
// if the ZeroThreshold had the provided larger (or equal) value. If the
// provided value is less than the histogram's ZeroThreshold, the method panics.

56
model/histogram/generic.go
Unescape View File

@ -17,6 +17,16 @@ import (
"fmt"
"math"
"strings"
"github.com/pkg/errors"
)
var (
ErrHistogramCountNotBigEnough = errors.New("histogram's observation count should be at least the number of observations found in the buckets")
ErrHistogramCountMismatch = errors.New("histogram's observation count should equal the number of observations found in the buckets (in absence of NaN)")
ErrHistogramNegativeBucketCount = errors.New("histogram has a bucket whose observation count is negative")
ErrHistogramSpanNegativeOffset = errors.New("histogram has a span whose offset is negative")
ErrHistogramSpansBucketsMismatch = errors.New("histogram spans specify different number of buckets than provided")
)
// BucketCount is a type constraint for the count in a bucket, which can be
@ -347,6 +357,52 @@ func compactBuckets[IBC InternalBucketCount](buckets []IBC, spans []Span, maxEmp
return buckets, spans
}
func checkHistogramSpans(spans []Span, numBuckets int) error {
var spanBuckets int
for n, span := range spans {
if n > 0 && span.Offset < 0 {
return errors.Wrap(
ErrHistogramSpanNegativeOffset,
fmt.Sprintf("span number %d with offset %d", n+1, span.Offset),
)
}
spanBuckets += int(span.Length)
}
if spanBuckets != numBuckets {
return errors.Wrap(
ErrHistogramSpansBucketsMismatch,
fmt.Sprintf("spans need %d buckets, have %d buckets", spanBuckets, numBuckets),
)
}
return nil
}
func checkHistogramBuckets[BC BucketCount, IBC InternalBucketCount](buckets []IBC, count *BC, deltas bool) error {
if len(buckets) == 0 {
return nil
}
var last IBC
for i := 0; i < len(buckets); i++ {
var c IBC
if deltas {
c = last + buckets[i]
} else {
c = buckets[i]
}
if c < 0 {
return errors.Wrap(
ErrHistogramNegativeBucketCount,
fmt.Sprintf("bucket number %d has observation count of %v", i+1, c),
)
}
last = c
*count += BC(c)
}
return nil
}
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

45
model/histogram/histogram.go
Unescape View File

@ -18,6 +18,7 @@ import (
"math"
"strings"
"github.com/pkg/errors"
"golang.org/x/exp/slices"
)
@ -328,6 +329,50 @@ func (h *Histogram) ToFloat() *FloatHistogram {
}
}
// Validate validates consistency between span and bucket slices. Also, buckets are checked
// against negative values.
// For histograms that have not observed any NaN values (based on IsNaN(h.Sum) check), a
// strict h.Count = nCount + pCount + h.ZeroCount check is performed.
// Otherwise, only a lower bound check will be done (h.Count >= nCount + pCount + h.ZeroCount),
// because NaN observations do not increment the values of buckets (but they do increment
// the total h.Count).
func (h *Histogram) Validate() error {
if err := checkHistogramSpans(h.NegativeSpans, len(h.NegativeBuckets)); err != nil {
return errors.Wrap(err, "negative side")
}
if err := checkHistogramSpans(h.PositiveSpans, len(h.PositiveBuckets)); err != nil {
return errors.Wrap(err, "positive side")
}
var nCount, pCount uint64
err := checkHistogramBuckets(h.NegativeBuckets, &nCount, true)
if err != nil {
return errors.Wrap(err, "negative side")
}
err = checkHistogramBuckets(h.PositiveBuckets, &pCount, true)
if err != nil {
return errors.Wrap(err, "positive side")
}
sumOfBuckets := nCount + pCount + h.ZeroCount
if math.IsNaN(h.Sum) {
if sumOfBuckets > h.Count {
return errors.Wrap(
ErrHistogramCountNotBigEnough,
fmt.Sprintf("%d observations found in buckets, but the Count field is %d", sumOfBuckets, h.Count),
)
}
} else {
if sumOfBuckets != h.Count {
return errors.Wrap(
ErrHistogramCountMismatch,
fmt.Sprintf("%d observations found in buckets, but the Count field is %d", sumOfBuckets, h.Count),
)
}
}
return nil
}
type regularBucketIterator struct {
baseBucketIterator[uint64, int64]
}

156
model/histogram/histogram_test.go
Unescape View File

@ -811,3 +811,159 @@ func TestHistogramCompact(t *testing.T) {
})
}
}
func TestHistogramValidation(t *testing.T) {
tests := map[string]struct {
h *Histogram
errMsg string
skipFloat bool
}{
"valid histogram": {
h: &Histogram{
Count: 12,
ZeroCount: 2,
ZeroThreshold: 0.001,
Sum: 19.4,
Schema: 1,
PositiveSpans: []Span{
{Offset: 0, Length: 2},
{Offset: 1, Length: 2},
},
PositiveBuckets: []int64{1, 1, -1, 0},
NegativeSpans: []Span{
{Offset: 0, Length: 2},
{Offset: 1, Length: 2},
},
NegativeBuckets: []int64{1, 1, -1, 0},
},
},
"valid histogram with NaN observations that has its Count (4) higher than the actual total of buckets (2 + 1)": {
// This case is possible if NaN values (which do not fall into any bucket) are observed.
h: &Histogram{
ZeroCount: 2,
Count: 4,
Sum: math.NaN(),
PositiveSpans: []Span{{Offset: 0, Length: 1}},
PositiveBuckets: []int64{1},
},
},
"rejects histogram without NaN observations that has its Count (4) higher than the actual total of buckets (2 + 1)": {
h: &Histogram{
ZeroCount: 2,
Count: 4,
Sum: 333,
PositiveSpans: []Span{{Offset: 0, Length: 1}},
PositiveBuckets: []int64{1},
},
errMsg: `3 observations found in buckets, but the Count field is 4: histogram's observation count should equal the number of observations found in the buckets (in absence of NaN)`,
skipFloat: true,
},
"rejects histogram that has too few negative buckets": {
h: &Histogram{
NegativeSpans: []Span{{Offset: 0, Length: 1}},
NegativeBuckets: []int64{},
},
errMsg: `negative side: spans need 1 buckets, have 0 buckets: histogram spans specify different number of buckets than provided`,
},
"rejects histogram that has too few positive buckets": {
h: &Histogram{
PositiveSpans: []Span{{Offset: 0, Length: 1}},
PositiveBuckets: []int64{},
},
errMsg: `positive side: spans need 1 buckets, have 0 buckets: histogram spans specify different number of buckets than provided`,
},
"rejects histogram that has too many negative buckets": {
h: &Histogram{
NegativeSpans: []Span{{Offset: 0, Length: 1}},
NegativeBuckets: []int64{1, 2},
},
errMsg: `negative side: spans need 1 buckets, have 2 buckets: histogram spans specify different number of buckets than provided`,
},
"rejects histogram that has too many positive buckets": {
h: &Histogram{
PositiveSpans: []Span{{Offset: 0, Length: 1}},
PositiveBuckets: []int64{1, 2},
},
errMsg: `positive side: spans need 1 buckets, have 2 buckets: histogram spans specify different number of buckets than provided`,
},
"rejects a histogram that has a negative span with a negative offset": {
h: &Histogram{
NegativeSpans: []Span{{Offset: -1, Length: 1}, {Offset: -1, Length: 1}},
NegativeBuckets: []int64{1, 2},
},
errMsg: `negative side: span number 2 with offset -1: histogram has a span whose offset is negative`,
},
"rejects a histogram which has a positive span with a negative offset": {
h: &Histogram{
PositiveSpans: []Span{{Offset: -1, Length: 1}, {Offset: -1, Length: 1}},
PositiveBuckets: []int64{1, 2},
},
errMsg: `positive side: span number 2 with offset -1: histogram has a span whose offset is negative`,
},
"rejects a histogram that has a negative bucket with a negative count": {
h: &Histogram{
NegativeSpans: []Span{{Offset: -1, Length: 1}},
NegativeBuckets: []int64{-1},
},
errMsg: `negative side: bucket number 1 has observation count of -1: histogram has a bucket whose observation count is negative`,
},
"rejects a histogram that has a positive bucket with a negative count": {
h: &Histogram{
PositiveSpans: []Span{{Offset: -1, Length: 1}},
PositiveBuckets: []int64{-1},
},
errMsg: `positive side: bucket number 1 has observation count of -1: histogram has a bucket whose observation count is negative`,
},
"rejects a histogram that has a lower count than count in buckets": {
h: &Histogram{
Count: 0,
NegativeSpans: []Span{{Offset: -1, Length: 1}},
PositiveSpans: []Span{{Offset: -1, Length: 1}},
NegativeBuckets: []int64{1},
PositiveBuckets: []int64{1},
},
errMsg: `2 observations found in buckets, but the Count field is 0: histogram's observation count should equal the number of observations found in the buckets (in absence of NaN)`,
skipFloat: true,
},
"rejects a histogram that doesn't count the zero bucket in its count": {
h: &Histogram{
Count: 2,
ZeroCount: 1,
NegativeSpans: []Span{{Offset: -1, Length: 1}},
PositiveSpans: []Span{{Offset: -1, Length: 1}},
NegativeBuckets: []int64{1},
PositiveBuckets: []int64{1},
},
errMsg: `3 observations found in buckets, but the Count field is 2: histogram's observation count should equal the number of observations found in the buckets (in absence of NaN)`,
skipFloat: true,
},
}
for testName, tc := range tests {
t.Run(testName, func(t *testing.T) {
if err := tc.h.Validate(); tc.errMsg != "" {
require.EqualError(t, err, tc.errMsg)
} else {
require.NoError(t, err)
}
if tc.skipFloat {
return
}
fh := tc.h.ToFloat()
if err := fh.Validate(); tc.errMsg != "" {
require.EqualError(t, err, tc.errMsg)
} else {
require.NoError(t, err)
}
})
}
}
func BenchmarkHistogramValidation(b *testing.B) {
histograms := GenerateBigTestHistograms(b.N, 500)
b.ResetTimer()
for _, h := range histograms {
require.NoError(b, h.Validate())
}
}

136
model/histogram/validate.go
Unescape View File

@ -1,136 +0,0 @@
// 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 histogram
import (
"fmt"
"math"
"github.com/pkg/errors"
)
var (
ErrHistogramCountNotBigEnough = errors.New("histogram's observation count should be at least the number of observations found in the buckets")
ErrHistogramCountMismatch = errors.New("histogram's observation count should equal the number of observations found in the buckets (in absence of NaN)")
ErrHistogramNegativeBucketCount = errors.New("histogram has a bucket whose observation count is negative")
ErrHistogramSpanNegativeOffset = errors.New("histogram has a span whose offset is negative")
ErrHistogramSpansBucketsMismatch = errors.New("histogram spans specify different number of buckets than provided")
)
func ValidateHistogram(h *Histogram) error {
if err := checkHistogramSpans(h.NegativeSpans, len(h.NegativeBuckets)); err != nil {
return errors.Wrap(err, "negative side")
}
if err := checkHistogramSpans(h.PositiveSpans, len(h.PositiveBuckets)); err != nil {
return errors.Wrap(err, "positive side")
}
var nCount, pCount uint64
err := checkHistogramBuckets(h.NegativeBuckets, &nCount, true)
if err != nil {
return errors.Wrap(err, "negative side")
}
err = checkHistogramBuckets(h.PositiveBuckets, &pCount, true)
if err != nil {
return errors.Wrap(err, "positive side")
}
sumOfBuckets := nCount + pCount + h.ZeroCount
if math.IsNaN(h.Sum) {
if sumOfBuckets > h.Count {
return errors.Wrap(
ErrHistogramCountNotBigEnough,
fmt.Sprintf("%d observations found in buckets, but the Count field is %d", sumOfBuckets, h.Count),
)
}
} else {
if sumOfBuckets != h.Count {
return errors.Wrap(
ErrHistogramCountMismatch,
fmt.Sprintf("%d observations found in buckets, but the Count field is %d", sumOfBuckets, h.Count),
)
}
}
return nil
}
func ValidateFloatHistogram(h *FloatHistogram) error {
if err := checkHistogramSpans(h.NegativeSpans, len(h.NegativeBuckets)); err != nil {
return errors.Wrap(err, "negative side")
}
if err := checkHistogramSpans(h.PositiveSpans, len(h.PositiveBuckets)); err != nil {
return errors.Wrap(err, "positive side")
}
var nCount, pCount float64
err := checkHistogramBuckets(h.NegativeBuckets, &nCount, false)
if err != nil {
return errors.Wrap(err, "negative side")
}
err = checkHistogramBuckets(h.PositiveBuckets, &pCount, false)
if err != nil {
return errors.Wrap(err, "positive side")
}
// We do not check for h.Count being at least as large as the sum of the
// counts in the buckets because floating point precision issues can
// create false positives here.
return nil
}
func checkHistogramSpans(spans []Span, numBuckets int) error {
var spanBuckets int
for n, span := range spans {
if n > 0 && span.Offset < 0 {
return errors.Wrap(
ErrHistogramSpanNegativeOffset,
fmt.Sprintf("span number %d with offset %d", n+1, span.Offset),
)
}
spanBuckets += int(span.Length)
}
if spanBuckets != numBuckets {
return errors.Wrap(
ErrHistogramSpansBucketsMismatch,
fmt.Sprintf("spans need %d buckets, have %d buckets", spanBuckets, numBuckets),
)
}
return nil
}
func checkHistogramBuckets[BC BucketCount, IBC InternalBucketCount](buckets []IBC, count *BC, deltas bool) error {
if len(buckets) == 0 {
return nil
}
var last IBC
for i := 0; i < len(buckets); i++ {
var c IBC
if deltas {
c = last + buckets[i]
} else {
c = buckets[i]
}
if c < 0 {
return errors.Wrap(
ErrHistogramNegativeBucketCount,
fmt.Sprintf("bucket number %d has observation count of %v", i+1, c),
)
}
last = c
*count += BC(c)
}
return nil
}

175
model/histogram/validate_test.go
Unescape View File

@ -1,175 +0,0 @@
// 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 histogram
import (
"math"
"testing"
"github.com/stretchr/testify/require"
)
func TestHistogramValidation(t *testing.T) {
tests := map[string]struct {
h *Histogram
errMsg string
skipFloat bool
}{
"valid histogram": {
h: &Histogram{
Count: 12,
ZeroCount: 2,
ZeroThreshold: 0.001,
Sum: 19.4,
Schema: 1,
PositiveSpans: []Span{
{Offset: 0, Length: 2},
{Offset: 1, Length: 2},
},
PositiveBuckets: []int64{1, 1, -1, 0},
NegativeSpans: []Span{
{Offset: 0, Length: 2},
{Offset: 1, Length: 2},
},
NegativeBuckets: []int64{1, 1, -1, 0},
},
},
"valid histogram with NaN observations that has its Count (4) higher than the actual total of buckets (2 + 1)": {
// This case is possible if NaN values (which do not fall into any bucket) are observed.
h: &Histogram{
ZeroCount: 2,
Count: 4,
Sum: math.NaN(),
PositiveSpans: []Span{{Offset: 0, Length: 1}},
PositiveBuckets: []int64{1},
},
},
"rejects histogram without NaN observations that has its Count (4) higher than the actual total of buckets (2 + 1)": {
h: &Histogram{
ZeroCount: 2,
Count: 4,
Sum: 333,
PositiveSpans: []Span{{Offset: 0, Length: 1}},
PositiveBuckets: []int64{1},
},
errMsg: `3 observations found in buckets, but the Count field is 4: histogram's observation count should equal the number of observations found in the buckets (in absence of NaN)`,
skipFloat: true,
},
"rejects histogram that has too few negative buckets": {
h: &Histogram{
NegativeSpans: []Span{{Offset: 0, Length: 1}},
NegativeBuckets: []int64{},
},
errMsg: `negative side: spans need 1 buckets, have 0 buckets: histogram spans specify different number of buckets than provided`,
},
"rejects histogram that has too few positive buckets": {
h: &Histogram{
PositiveSpans: []Span{{Offset: 0, Length: 1}},
PositiveBuckets: []int64{},
},
errMsg: `positive side: spans need 1 buckets, have 0 buckets: histogram spans specify different number of buckets than provided`,
},
"rejects histogram that has too many negative buckets": {
h: &Histogram{
NegativeSpans: []Span{{Offset: 0, Length: 1}},
NegativeBuckets: []int64{1, 2},
},
errMsg: `negative side: spans need 1 buckets, have 2 buckets: histogram spans specify different number of buckets than provided`,
},
"rejects histogram that has too many positive buckets": {
h: &Histogram{
PositiveSpans: []Span{{Offset: 0, Length: 1}},
PositiveBuckets: []int64{1, 2},
},
errMsg: `positive side: spans need 1 buckets, have 2 buckets: histogram spans specify different number of buckets than provided`,
},
"rejects a histogram that has a negative span with a negative offset": {
h: &Histogram{
NegativeSpans: []Span{{Offset: -1, Length: 1}, {Offset: -1, Length: 1}},
NegativeBuckets: []int64{1, 2},
},
errMsg: `negative side: span number 2 with offset -1: histogram has a span whose offset is negative`,
},
"rejects a histogram which has a positive span with a negative offset": {
h: &Histogram{
PositiveSpans: []Span{{Offset: -1, Length: 1}, {Offset: -1, Length: 1}},
PositiveBuckets: []int64{1, 2},
},
errMsg: `positive side: span number 2 with offset -1: histogram has a span whose offset is negative`,
},
"rejects a histogram that has a negative bucket with a negative count": {
h: &Histogram{
NegativeSpans: []Span{{Offset: -1, Length: 1}},
NegativeBuckets: []int64{-1},
},
errMsg: `negative side: bucket number 1 has observation count of -1: histogram has a bucket whose observation count is negative`,
},
"rejects a histogram that has a positive bucket with a negative count": {
h: &Histogram{
PositiveSpans: []Span{{Offset: -1, Length: 1}},
PositiveBuckets: []int64{-1},
},
errMsg: `positive side: bucket number 1 has observation count of -1: histogram has a bucket whose observation count is negative`,
},
"rejects a histogram that has a lower count than count in buckets": {
h: &Histogram{
Count: 0,
NegativeSpans: []Span{{Offset: -1, Length: 1}},
PositiveSpans: []Span{{Offset: -1, Length: 1}},
NegativeBuckets: []int64{1},
PositiveBuckets: []int64{1},
},
errMsg: `2 observations found in buckets, but the Count field is 0: histogram's observation count should equal the number of observations found in the buckets (in absence of NaN)`,
skipFloat: true,
},
"rejects a histogram that doesn't count the zero bucket in its count": {
h: &Histogram{
Count: 2,
ZeroCount: 1,
NegativeSpans: []Span{{Offset: -1, Length: 1}},
PositiveSpans: []Span{{Offset: -1, Length: 1}},
NegativeBuckets: []int64{1},
PositiveBuckets: []int64{1},
},
errMsg: `3 observations found in buckets, but the Count field is 2: histogram's observation count should equal the number of observations found in the buckets (in absence of NaN)`,
skipFloat: true,
},
}
for testName, tc := range tests {
t.Run(testName, func(t *testing.T) {
if err := ValidateHistogram(tc.h); tc.errMsg != "" {
require.EqualError(t, err, tc.errMsg)
} else {
require.NoError(t, err)
}
if tc.skipFloat {
return
}
if err := ValidateFloatHistogram(tc.h.ToFloat()); tc.errMsg != "" {
require.EqualError(t, err, tc.errMsg)
} else {
require.NoError(t, err)
}
})
}
}
func BenchmarkHistogramValidation(b *testing.B) {
histograms := GenerateBigTestHistograms(b.N, 500)
b.ResetTimer()
for _, h := range histograms {
require.NoError(b, ValidateHistogram(h))
}
}

4
tsdb/agent/db.go
Unescape View File

@ -883,13 +883,13 @@ func (a *appender) AppendExemplar(ref storage.SeriesRef, _ labels.Labels, e exem
func (a *appender) AppendHistogram(ref storage.SeriesRef, l labels.Labels, t int64, h *histogram.Histogram, fh *histogram.FloatHistogram) (storage.SeriesRef, error) {
if h != nil {
if err := histogram.ValidateHistogram(h); err != nil {
if err := h.Validate(); err != nil {
return 0, err
}
}
if fh != nil {
if err := histogram.ValidateFloatHistogram(fh); err != nil {
if err := fh.Validate(); err != nil {
return 0, err
}
}

4
tsdb/head_append.go
Unescape View File

@ -521,13 +521,13 @@ func (a *headAppender) AppendHistogram(ref storage.SeriesRef, lset labels.Labels
}
if h != nil {
if err := histogram.ValidateHistogram(h); err != nil {
if err := h.Validate(); err != nil {
return 0, err
}
}
if fh != nil {
if err := histogram.ValidateFloatHistogram(fh); err != nil {
if err := fh.Validate(); err != nil {
return 0, err
}
}

Write Preview
Loading…
Cancel
Save