prometheus/tsdb/chunkenc/float_histogram_test.go
beorn7 c3c7d44d84 lint: Adjust to the lint warnings raised by current versions of golint-ci
We haven't updated golint-ci in our CI yet, but this commit prepares
for that.

There are a lot of new warnings, and it is mostly because the "revive"
linter got updated. I agree with most of the new warnings, mostly
around not naming unused function parameters (although it is justified
in some cases for documentation purposes – while things like mocks are
a good example where not naming the parameter is clearer).

I'm pretty upset about the "empty block" warning to include `for`
loops. It's such a common pattern to do something in the head of the
`for` loop and then have an empty block. There is still an open issue
about this: https://github.com/mgechev/revive/issues/810 I have
disabled "revive" altogether in files where empty blocks are used
excessively, and I have made the effort to add individual
`// nolint:revive` where empty blocks are used just once or twice.
It's borderline noisy, though, but let's go with it for now.

I should mention that none of the "empty block" warnings for `for`
loop bodies were legitimate.

Signed-off-by: beorn7 <beorn@grafana.com>
2023-04-19 17:10:10 +02:00

535 lines
16 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 { // nolint:revive
// 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)
}
}