prometheus/tsdb/chunkenc/float_histogram_test.go
beorn7 1cfc8f65a3 histograms: Return actually useful counter reset hints
This is a bit more conservative than we could be. As long as a chunk
isn't the first in a block, we can be pretty sure that the previous
chunk won't disappear. However, the incremental gain of returning
NotCounterReset in these cases is probably very small and might not be
worth the code complications.

Wwith this, we now also pay attention to an explicitly set counter
reset during ingestion. While the case doesn't show up in practice
yet, there could be scenarios where the metric source knows there was
a counter reset even if it might not be visible from the values in the
histogram. It is also useful for testing.

Signed-off-by: beorn7 <beorn@grafana.com>
2023-01-25 16:57:21 +01:00

535 lines
15 KiB
Go

// Copyright 2021 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 chunkenc
import (
"testing"
"github.com/stretchr/testify/require"
"github.com/prometheus/prometheus/model/histogram"
)
type floatResult struct {
t int64
h *histogram.FloatHistogram
}
func TestFloatHistogramChunkSameBuckets(t *testing.T) {
c := NewFloatHistogramChunk()
var exp []floatResult
// Create fresh appender and add the first histogram.
app, err := c.Appender()
require.NoError(t, err)
require.Equal(t, 0, c.NumSamples())
ts := int64(1234567890)
h := &histogram.Histogram{
Count: 15,
ZeroCount: 2,
Sum: 18.4,
ZeroThreshold: 1e-100,
Schema: 1,
PositiveSpans: []histogram.Span{
{Offset: 0, Length: 2},
{Offset: 1, Length: 2},
},
PositiveBuckets: []int64{1, 1, -1, 0}, // counts: 1, 2, 1, 1 (total 5)
NegativeSpans: []histogram.Span{
{Offset: 1, Length: 1},
{Offset: 2, Length: 3},
},
NegativeBuckets: []int64{2, 1, -1, -1}, // counts: 2, 3, 2, 1 (total 8)
}
app.AppendFloatHistogram(ts, h.ToFloat())
exp = append(exp, floatResult{t: ts, h: h.ToFloat()})
require.Equal(t, 1, c.NumSamples())
// Add an updated histogram.
ts += 16
h = h.Copy()
h.Count = 32
h.ZeroCount++
h.Sum = 24.4
h.PositiveBuckets = []int64{5, -2, 1, -2} // counts: 5, 3, 4, 2 (total 14)
h.NegativeBuckets = []int64{4, -1, 1, -1} // counts: 4, 3, 4, 4 (total 15)
app.AppendFloatHistogram(ts, h.ToFloat())
expH := h.ToFloat()
expH.CounterResetHint = histogram.NotCounterReset
exp = append(exp, floatResult{t: ts, h: expH})
require.Equal(t, 2, c.NumSamples())
// Add update with new appender.
app, err = c.Appender()
require.NoError(t, err)
ts += 14
h = h.Copy()
h.Count = 54
h.ZeroCount += 2
h.Sum = 24.4
h.PositiveBuckets = []int64{6, 1, -3, 6} // counts: 6, 7, 4, 10 (total 27)
h.NegativeBuckets = []int64{5, 1, -2, 3} // counts: 5, 6, 4, 7 (total 22)
app.AppendFloatHistogram(ts, h.ToFloat())
expH = h.ToFloat()
expH.CounterResetHint = histogram.NotCounterReset
exp = append(exp, floatResult{t: ts, h: expH})
require.Equal(t, 3, c.NumSamples())
// 1. Expand iterator in simple case.
it := c.Iterator(nil)
require.NoError(t, it.Err())
var act []floatResult
for it.Next() == ValFloatHistogram {
fts, fh := it.AtFloatHistogram()
act = append(act, floatResult{t: fts, h: fh})
}
require.NoError(t, it.Err())
require.Equal(t, exp, act)
// 2. Expand second iterator while reusing first one.
it2 := c.Iterator(it)
var act2 []floatResult
for it2.Next() == ValFloatHistogram {
fts, fh := it2.AtFloatHistogram()
act2 = append(act2, floatResult{t: fts, h: fh})
}
require.NoError(t, it2.Err())
require.Equal(t, exp, act2)
// 3. Now recycle an iterator that was never used to access anything.
itX := c.Iterator(nil)
for itX.Next() == ValFloatHistogram {
// Just iterate through without accessing anything.
}
it3 := c.iterator(itX)
var act3 []floatResult
for it3.Next() == ValFloatHistogram {
fts, fh := it3.AtFloatHistogram()
act3 = append(act3, floatResult{t: fts, h: fh})
}
require.NoError(t, it3.Err())
require.Equal(t, exp, act3)
// 4. Test iterator Seek.
mid := len(exp) / 2
it4 := c.Iterator(nil)
var act4 []floatResult
require.Equal(t, ValFloatHistogram, it4.Seek(exp[mid].t))
// Below ones should not matter.
require.Equal(t, ValFloatHistogram, it4.Seek(exp[mid].t))
require.Equal(t, ValFloatHistogram, it4.Seek(exp[mid].t))
fts, fh := it4.AtFloatHistogram()
act4 = append(act4, floatResult{t: fts, h: fh})
for it4.Next() == ValFloatHistogram {
fts, fh := it4.AtFloatHistogram()
act4 = append(act4, floatResult{t: fts, h: fh})
}
require.NoError(t, it4.Err())
require.Equal(t, exp[mid:], act4)
require.Equal(t, ValNone, it4.Seek(exp[len(exp)-1].t+1))
}
// Mimics the scenario described for expandSpansForward.
func TestFloatHistogramChunkBucketChanges(t *testing.T) {
c := Chunk(NewFloatHistogramChunk())
// Create fresh appender and add the first histogram.
app, err := c.Appender()
require.NoError(t, err)
require.Equal(t, 0, c.NumSamples())
ts1 := int64(1234567890)
h1 := &histogram.Histogram{
Count: 27,
ZeroCount: 2,
Sum: 18.4,
ZeroThreshold: 1e-125,
Schema: 1,
PositiveSpans: []histogram.Span{
{Offset: 0, Length: 2},
{Offset: 2, Length: 1},
{Offset: 3, Length: 2},
{Offset: 3, Length: 1},
{Offset: 1, Length: 1},
},
PositiveBuckets: []int64{6, -3, 0, -1, 2, 1, -4}, // counts: 6, 3, 3, 2, 4, 5, 1 (total 24)
NegativeSpans: []histogram.Span{{Offset: 1, Length: 1}},
NegativeBuckets: []int64{1},
}
app.AppendFloatHistogram(ts1, h1.ToFloat())
require.Equal(t, 1, c.NumSamples())
// Add a new histogram that has expanded buckets.
ts2 := ts1 + 16
h2 := h1.Copy()
h2.PositiveSpans = []histogram.Span{
{Offset: 0, Length: 3},
{Offset: 1, Length: 1},
{Offset: 1, Length: 4},
{Offset: 3, Length: 3},
}
h2.NegativeSpans = []histogram.Span{{Offset: 0, Length: 2}}
h2.Count = 35
h2.ZeroCount++
h2.Sum = 30
// Existing histogram should get values converted from the above to:
// 6 3 0 3 0 0 2 4 5 0 1 (previous values with some new empty buckets in between)
// so the new histogram should have new counts >= these per-bucket counts, e.g.:
h2.PositiveBuckets = []int64{7, -2, -4, 2, -2, -1, 2, 3, 0, -5, 1} // 7 5 1 3 1 0 2 5 5 0 1 (total 30)
// Existing histogram should get values converted from the above to:
// 0 1 (previous values with some new empty buckets in between)
// so the new histogram should have new counts >= these per-bucket counts, e.g.:
h2.NegativeBuckets = []int64{2, -1} // 2 1 (total 3)
// This is how span changes will be handled.
hApp, _ := app.(*FloatHistogramAppender)
posInterjections, negInterjections, ok, cr := hApp.Appendable(h2.ToFloat())
require.Greater(t, len(posInterjections), 0)
require.Greater(t, len(negInterjections), 0)
require.True(t, ok) // Only new buckets came in.
require.False(t, cr)
c, app = hApp.Recode(posInterjections, negInterjections, h2.PositiveSpans, h2.NegativeSpans)
app.AppendFloatHistogram(ts2, h2.ToFloat())
require.Equal(t, 2, c.NumSamples())
// Because the 2nd histogram has expanded buckets, we should expect all
// histograms (in particular the first) to come back using the new spans
// metadata as well as the expanded buckets.
h1.PositiveSpans = h2.PositiveSpans
h1.PositiveBuckets = []int64{6, -3, -3, 3, -3, 0, 2, 2, 1, -5, 1}
h1.NegativeSpans = h2.NegativeSpans
h1.NegativeBuckets = []int64{0, 1}
expH2 := h2.ToFloat()
expH2.CounterResetHint = histogram.NotCounterReset
exp := []floatResult{
{t: ts1, h: h1.ToFloat()},
{t: ts2, h: expH2},
}
it := c.Iterator(nil)
var act []floatResult
for it.Next() == ValFloatHistogram {
fts, fh := it.AtFloatHistogram()
act = append(act, floatResult{t: fts, h: fh})
}
require.NoError(t, it.Err())
require.Equal(t, exp, act)
}
func TestFloatHistogramChunkAppendable(t *testing.T) {
c := Chunk(NewFloatHistogramChunk())
// Create fresh appender and add the first histogram.
app, err := c.Appender()
require.NoError(t, err)
require.Equal(t, 0, c.NumSamples())
ts := int64(1234567890)
h1 := &histogram.FloatHistogram{
Count: 5,
ZeroCount: 2,
Sum: 18.4,
ZeroThreshold: 1e-125,
Schema: 1,
PositiveSpans: []histogram.Span{
{Offset: 0, Length: 2},
{Offset: 2, Length: 1},
{Offset: 3, Length: 2},
{Offset: 3, Length: 1},
{Offset: 1, Length: 1},
},
PositiveBuckets: []float64{6, 3, 3, 2, 4, 5, 1},
}
app.AppendFloatHistogram(ts, h1.Copy())
require.Equal(t, 1, c.NumSamples())
hApp, _ := app.(*FloatHistogramAppender)
{ // Schema change.
h2 := h1.Copy()
h2.Schema++
_, _, ok, _ := hApp.Appendable(h2)
require.False(t, ok)
}
{ // Zero threshold change.
h2 := h1.Copy()
h2.ZeroThreshold += 0.1
_, _, ok, _ := hApp.Appendable(h2)
require.False(t, ok)
}
{ // New histogram that has more buckets.
h2 := h1.Copy()
h2.PositiveSpans = []histogram.Span{
{Offset: 0, Length: 3},
{Offset: 1, Length: 1},
{Offset: 1, Length: 4},
{Offset: 3, Length: 3},
}
h2.Count += 9
h2.ZeroCount++
h2.Sum = 30
h2.PositiveBuckets = []float64{7, 5, 1, 3, 1, 0, 2, 5, 5, 0, 1}
posInterjections, negInterjections, ok, cr := hApp.Appendable(h2)
require.Greater(t, len(posInterjections), 0)
require.Equal(t, 0, len(negInterjections))
require.True(t, ok) // Only new buckets came in.
require.False(t, cr)
}
{ // New histogram that has a bucket missing.
h2 := h1.Copy()
h2.PositiveSpans = []histogram.Span{
{Offset: 0, Length: 2},
{Offset: 5, Length: 2},
{Offset: 3, Length: 1},
{Offset: 1, Length: 1},
}
h2.Sum = 21
h2.PositiveBuckets = []float64{6, 3, 2, 4, 5, 1}
posInterjections, negInterjections, ok, cr := hApp.Appendable(h2)
require.Equal(t, 0, len(posInterjections))
require.Equal(t, 0, len(negInterjections))
require.False(t, ok) // Need to cut a new chunk.
require.True(t, cr)
}
{ // New histogram that has a counter reset while buckets are same.
h2 := h1.Copy()
h2.Sum = 23
h2.PositiveBuckets = []float64{6, 2, 3, 2, 4, 5, 1}
posInterjections, negInterjections, ok, cr := hApp.Appendable(h2)
require.Equal(t, 0, len(posInterjections))
require.Equal(t, 0, len(negInterjections))
require.False(t, ok) // Need to cut a new chunk.
require.True(t, cr)
}
{ // New histogram that has a counter reset while new buckets were added.
h2 := h1.Copy()
h2.PositiveSpans = []histogram.Span{
{Offset: 0, Length: 3},
{Offset: 1, Length: 1},
{Offset: 1, Length: 4},
{Offset: 3, Length: 3},
}
h2.Sum = 29
h2.PositiveBuckets = []float64{7, 5, 1, 3, 1, 0, 2, 5, 5, 0, 0}
posInterjections, negInterjections, ok, cr := hApp.Appendable(h2)
require.Equal(t, 0, len(posInterjections))
require.Equal(t, 0, len(negInterjections))
require.False(t, ok) // Need to cut a new chunk.
require.True(t, cr)
}
{
// New histogram that has a counter reset while new buckets were
// added before the first bucket and reset on first bucket. (to
// catch the edge case where the new bucket should be forwarded
// ahead until first old bucket at start)
h2 := h1.Copy()
h2.PositiveSpans = []histogram.Span{
{Offset: -3, Length: 2},
{Offset: 1, Length: 2},
{Offset: 2, Length: 1},
{Offset: 3, Length: 2},
{Offset: 3, Length: 1},
{Offset: 1, Length: 1},
}
h2.Sum = 26
h2.PositiveBuckets = []float64{1, 2, 5, 3, 3, 2, 4, 5, 1}
posInterjections, negInterjections, ok, cr := hApp.Appendable(h2)
require.Equal(t, 0, len(posInterjections))
require.Equal(t, 0, len(negInterjections))
require.False(t, ok) // Need to cut a new chunk.
require.True(t, cr)
}
}
func TestFloatHistogramChunkAppendableGauge(t *testing.T) {
c := Chunk(NewFloatHistogramChunk())
// Create fresh appender and add the first histogram.
app, err := c.Appender()
require.NoError(t, err)
require.Equal(t, 0, c.NumSamples())
ts := int64(1234567890)
h1 := &histogram.FloatHistogram{
Count: 5,
ZeroCount: 2,
Sum: 18.4,
ZeroThreshold: 1e-125,
Schema: 1,
PositiveSpans: []histogram.Span{
{Offset: 0, Length: 2},
{Offset: 2, Length: 1},
{Offset: 3, Length: 2},
{Offset: 3, Length: 1},
{Offset: 1, Length: 1},
},
PositiveBuckets: []float64{6, 3, 3, 2, 4, 5, 1},
}
app.AppendFloatHistogram(ts, h1.Copy())
require.Equal(t, 1, c.NumSamples())
c.(*FloatHistogramChunk).SetCounterResetHeader(GaugeType)
{ // Schema change.
h2 := h1.Copy()
h2.Schema++
hApp, _ := app.(*FloatHistogramAppender)
_, _, _, _, _, _, ok := hApp.AppendableGauge(h2)
require.False(t, ok)
}
{ // Zero threshold change.
h2 := h1.Copy()
h2.ZeroThreshold += 0.1
hApp, _ := app.(*FloatHistogramAppender)
_, _, _, _, _, _, ok := hApp.AppendableGauge(h2)
require.False(t, ok)
}
{ // New histogram that has more buckets.
h2 := h1.Copy()
h2.PositiveSpans = []histogram.Span{
{Offset: 0, Length: 3},
{Offset: 1, Length: 1},
{Offset: 1, Length: 4},
{Offset: 3, Length: 3},
}
h2.Count += 9
h2.ZeroCount++
h2.Sum = 30
h2.PositiveBuckets = []float64{7, 5, 1, 3, 1, 0, 2, 5, 5, 0, 1}
hApp, _ := app.(*FloatHistogramAppender)
pI, nI, pBackwardI, nBackwardI, _, _, ok := hApp.AppendableGauge(h2)
require.Greater(t, len(pI), 0)
require.Len(t, nI, 0)
require.Len(t, pBackwardI, 0)
require.Len(t, nBackwardI, 0)
require.True(t, ok)
}
{ // New histogram that has buckets missing.
h2 := h1.Copy()
h2.PositiveSpans = []histogram.Span{
{Offset: 0, Length: 2},
{Offset: 2, Length: 1},
{Offset: 3, Length: 1},
{Offset: 4, Length: 1},
{Offset: 1, Length: 1},
}
h2.Count -= 4
h2.Sum--
h2.PositiveBuckets = []float64{6, 3, 3, 2, 5, 1}
hApp, _ := app.(*FloatHistogramAppender)
pI, nI, pBackwardI, nBackwardI, _, _, ok := hApp.AppendableGauge(h2)
require.Len(t, pI, 0)
require.Len(t, nI, 0)
require.Greater(t, len(pBackwardI), 0)
require.Len(t, nBackwardI, 0)
require.True(t, ok)
}
{ // New histogram that has a bucket missing and new buckets.
h2 := h1.Copy()
h2.PositiveSpans = []histogram.Span{
{Offset: 0, Length: 2},
{Offset: 5, Length: 2},
{Offset: 3, Length: 1},
{Offset: 1, Length: 1},
}
h2.Sum = 21
h2.PositiveBuckets = []float64{6, 3, 2, 4, 5, 1}
hApp, _ := app.(*FloatHistogramAppender)
pI, nI, pBackwardI, nBackwardI, _, _, ok := hApp.AppendableGauge(h2)
require.Greater(t, len(pI), 0)
require.Greater(t, len(pBackwardI), 0)
require.Len(t, nI, 0)
require.Len(t, nBackwardI, 0)
require.True(t, ok)
}
{ // New histogram that has a counter reset while buckets are same.
h2 := h1.Copy()
h2.Sum = 23
h2.PositiveBuckets = []float64{6, 2, 3, 2, 4, 5, 1}
hApp, _ := app.(*FloatHistogramAppender)
pI, nI, pBackwardI, nBackwardI, _, _, ok := hApp.AppendableGauge(h2)
require.Len(t, pI, 0)
require.Len(t, nI, 0)
require.Len(t, pBackwardI, 0)
require.Len(t, nBackwardI, 0)
require.True(t, ok)
}
{ // New histogram that has a counter reset while new buckets were added.
h2 := h1.Copy()
h2.PositiveSpans = []histogram.Span{
{Offset: 0, Length: 3},
{Offset: 1, Length: 1},
{Offset: 1, Length: 4},
{Offset: 3, Length: 3},
}
h2.Sum = 29
h2.PositiveBuckets = []float64{7, 5, 1, 3, 1, 0, 2, 5, 5, 0, 0}
hApp, _ := app.(*FloatHistogramAppender)
pI, nI, pBackwardI, nBackwardI, _, _, ok := hApp.AppendableGauge(h2)
require.Greater(t, len(pI), 0)
require.Len(t, nI, 0)
require.Len(t, pBackwardI, 0)
require.Len(t, nBackwardI, 0)
require.True(t, ok)
}
{
// New histogram that has a counter reset while new buckets were
// added before the first bucket and reset on first bucket.
h2 := h1.Copy()
h2.PositiveSpans = []histogram.Span{
{Offset: -3, Length: 2},
{Offset: 1, Length: 2},
{Offset: 2, Length: 1},
{Offset: 3, Length: 2},
{Offset: 3, Length: 1},
{Offset: 1, Length: 1},
}
h2.Sum = 26
h2.PositiveBuckets = []float64{1, 2, 5, 3, 3, 2, 4, 5, 1}
hApp, _ := app.(*FloatHistogramAppender)
pI, nI, pBackwardI, nBackwardI, _, _, ok := hApp.AppendableGauge(h2)
require.Greater(t, len(pI), 0)
require.Len(t, nI, 0)
require.Len(t, pBackwardI, 0)
require.Len(t, nBackwardI, 0)
require.True(t, ok)
}
}