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prometheus/tsdb/wlog/watcher_test.go

811 lines
23 KiB

// Copyright 2018 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 wlog
import (
"fmt"
"math/rand"
"os"
"path"
"runtime"
"sync"
"testing"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/promslog"
"github.com/stretchr/testify/require"
"golang.org/x/sync/errgroup"
"github.com/prometheus/prometheus/model/histogram"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/tsdb/chunks"
"github.com/prometheus/prometheus/tsdb/record"
)
var (
defaultRetryInterval = 100 * time.Millisecond
defaultRetries = 100
wMetrics = NewWatcherMetrics(prometheus.DefaultRegisterer)
)
// retry executes f() n times at each interval until it returns true.
func retry(t *testing.T, interval time.Duration, n int, f func() bool) {
t.Helper()
ticker := time.NewTicker(interval)
for i := 0; i <= n; i++ {
if f() {
return
}
<-ticker.C
}
ticker.Stop()
t.Logf("function returned false")
}
// Overwrite readTimeout defined in watcher.go.
func overwriteReadTimeout(t *testing.T, val time.Duration) {
initialVal := readTimeout
readTimeout = val
t.Cleanup(func() { readTimeout = initialVal })
}
type writeToMock struct {
samplesAppended int
exemplarsAppended int
histogramsAppended int
floatHistogramsAppended int
seriesLock sync.Mutex
seriesSegmentIndexes map[chunks.HeadSeriesRef]int
// If nonzero, delay reads with a short sleep.
delay time.Duration
}
func (wtm *writeToMock) Append(s []record.RefSample) bool {
time.Sleep(wtm.delay)
wtm.samplesAppended += len(s)
return true
}
func (wtm *writeToMock) AppendExemplars(e []record.RefExemplar) bool {
time.Sleep(wtm.delay)
wtm.exemplarsAppended += len(e)
return true
}
func (wtm *writeToMock) AppendHistograms(h []record.RefHistogramSample) bool {
time.Sleep(wtm.delay)
wtm.histogramsAppended += len(h)
return true
}
func (wtm *writeToMock) AppendFloatHistograms(fh []record.RefFloatHistogramSample) bool {
time.Sleep(wtm.delay)
wtm.floatHistogramsAppended += len(fh)
return true
}
func (wtm *writeToMock) StoreSeries(series []record.RefSeries, index int) {
time.Sleep(wtm.delay)
wtm.UpdateSeriesSegment(series, index)
}
func (wtm *writeToMock) StoreMetadata(_ []record.RefMetadata) { /* no-op */ }
func (wtm *writeToMock) UpdateSeriesSegment(series []record.RefSeries, index int) {
wtm.seriesLock.Lock()
defer wtm.seriesLock.Unlock()
for _, s := range series {
wtm.seriesSegmentIndexes[s.Ref] = index
}
}
func (wtm *writeToMock) SeriesReset(index int) {
// Check for series that are in segments older than the checkpoint
// that were not also present in the checkpoint.
wtm.seriesLock.Lock()
defer wtm.seriesLock.Unlock()
for k, v := range wtm.seriesSegmentIndexes {
if v < index {
delete(wtm.seriesSegmentIndexes, k)
}
}
}
func (wtm *writeToMock) checkNumSeries() int {
wtm.seriesLock.Lock()
defer wtm.seriesLock.Unlock()
return len(wtm.seriesSegmentIndexes)
}
func newWriteToMock(delay time.Duration) *writeToMock {
return &writeToMock{
seriesSegmentIndexes: make(map[chunks.HeadSeriesRef]int),
delay: delay,
}
}
func TestTailSamples(t *testing.T) {
pageSize := 32 * 1024
const seriesCount = 10
const samplesCount = 250
const exemplarsCount = 25
const histogramsCount = 50
for _, compress := range []CompressionType{CompressionNone, CompressionSnappy, CompressionZstd} {
t.Run(fmt.Sprintf("compress=%s", compress), func(t *testing.T) {
now := time.Now()
dir := t.TempDir()
wdir := path.Join(dir, "wal")
err := os.Mkdir(wdir, 0o777)
require.NoError(t, err)
enc := record.Encoder{}
w, err := NewSize(nil, nil, wdir, 128*pageSize, compress)
require.NoError(t, err)
defer func() {
require.NoError(t, w.Close())
}()
// Write to the initial segment then checkpoint.
for i := 0; i < seriesCount; i++ {
ref := i + 100
series := enc.Series([]record.RefSeries{
{
Ref: chunks.HeadSeriesRef(ref),
Labels: labels.FromStrings("__name__", fmt.Sprintf("metric_%d", i)),
},
}, nil)
require.NoError(t, w.Log(series))
for j := 0; j < samplesCount; j++ {
inner := rand.Intn(ref + 1)
sample := enc.Samples([]record.RefSample{
{
Ref: chunks.HeadSeriesRef(inner),
T: now.UnixNano() + 1,
V: float64(i),
},
}, nil)
require.NoError(t, w.Log(sample))
}
for j := 0; j < exemplarsCount; j++ {
inner := rand.Intn(ref + 1)
exemplar := enc.Exemplars([]record.RefExemplar{
{
Ref: chunks.HeadSeriesRef(inner),
T: now.UnixNano() + 1,
V: float64(i),
Labels: labels.FromStrings("trace_id", fmt.Sprintf("trace-%d", inner)),
},
}, nil)
require.NoError(t, w.Log(exemplar))
}
for j := 0; j < histogramsCount; j++ {
inner := rand.Intn(ref + 1)
hist := &histogram.Histogram{
Schema: 2,
ZeroThreshold: 1e-128,
ZeroCount: 0,
Count: 2,
Sum: 0,
PositiveSpans: []histogram.Span{{Offset: 0, Length: 1}},
PositiveBuckets: []int64{int64(i) + 1},
NegativeSpans: []histogram.Span{{Offset: 0, Length: 1}},
NegativeBuckets: []int64{int64(-i) - 1},
}
histogram := enc.HistogramSamples([]record.RefHistogramSample{{
Ref: chunks.HeadSeriesRef(inner),
T: now.UnixNano() + 1,
H: hist,
}}, nil)
require.NoError(t, w.Log(histogram))
floatHistogram := enc.FloatHistogramSamples([]record.RefFloatHistogramSample{{
Ref: chunks.HeadSeriesRef(inner),
T: now.UnixNano() + 1,
FH: hist.ToFloat(nil),
}}, nil)
require.NoError(t, w.Log(floatHistogram))
}
}
// Start read after checkpoint, no more data written.
first, last, err := Segments(w.Dir())
require.NoError(t, err)
wt := newWriteToMock(0)
watcher := NewWatcher(wMetrics, nil, nil, "", wt, dir, true, true, true)
watcher.SetStartTime(now)
// Set the Watcher's metrics so they're not nil pointers.
watcher.setMetrics()
for i := first; i <= last; i++ {
segment, err := OpenReadSegment(SegmentName(watcher.walDir, i))
require.NoError(t, err)
reader := NewLiveReader(nil, NewLiveReaderMetrics(nil), segment)
// Use tail true so we can ensure we got the right number of samples.
watcher.readSegment(reader, i, true)
require.NoError(t, segment.Close())
}
expectedSeries := seriesCount
expectedSamples := seriesCount * samplesCount
expectedExemplars := seriesCount * exemplarsCount
expectedHistograms := seriesCount * histogramsCount
retry(t, defaultRetryInterval, defaultRetries, func() bool {
return wt.checkNumSeries() >= expectedSeries
})
require.Equal(t, expectedSeries, wt.checkNumSeries(), "did not receive the expected number of series")
require.Equal(t, expectedSamples, wt.samplesAppended, "did not receive the expected number of samples")
require.Equal(t, expectedExemplars, wt.exemplarsAppended, "did not receive the expected number of exemplars")
require.Equal(t, expectedHistograms, wt.histogramsAppended, "did not receive the expected number of histograms")
require.Equal(t, expectedHistograms, wt.floatHistogramsAppended, "did not receive the expected number of float histograms")
})
}
}
func TestReadToEndNoCheckpoint(t *testing.T) {
pageSize := 32 * 1024
const seriesCount = 10
const samplesCount = 250
for _, compress := range []CompressionType{CompressionNone, CompressionSnappy, CompressionZstd} {
t.Run(fmt.Sprintf("compress=%s", compress), func(t *testing.T) {
dir := t.TempDir()
wdir := path.Join(dir, "wal")
err := os.Mkdir(wdir, 0o777)
require.NoError(t, err)
w, err := NewSize(nil, nil, wdir, 128*pageSize, compress)
require.NoError(t, err)
defer func() {
require.NoError(t, w.Close())
}()
var recs [][]byte
enc := record.Encoder{}
for i := 0; i < seriesCount; i++ {
series := enc.Series([]record.RefSeries{
{
Ref: chunks.HeadSeriesRef(i),
Labels: labels.FromStrings("__name__", fmt.Sprintf("metric_%d", i)),
},
}, nil)
recs = append(recs, series)
for j := 0; j < samplesCount; j++ {
sample := enc.Samples([]record.RefSample{
{
Ref: chunks.HeadSeriesRef(j),
T: int64(i),
V: float64(i),
},
}, nil)
recs = append(recs, sample)
// Randomly batch up records.
if rand.Intn(4) < 3 {
require.NoError(t, w.Log(recs...))
recs = recs[:0]
}
}
}
require.NoError(t, w.Log(recs...))
overwriteReadTimeout(t, time.Second)
_, _, err = Segments(w.Dir())
require.NoError(t, err)
wt := newWriteToMock(0)
watcher := NewWatcher(wMetrics, nil, nil, "", wt, dir, false, false, false)
go watcher.Start()
expected := seriesCount
require.Eventually(t, func() bool {
return wt.checkNumSeries() == expected
}, 20*time.Second, 1*time.Second)
watcher.Stop()
})
}
}
func TestReadToEndWithCheckpoint(t *testing.T) {
segmentSize := 32 * 1024
// We need something similar to this # of series and samples
// in order to get enough segments for us to checkpoint.
const seriesCount = 10
const samplesCount = 250
for _, compress := range []CompressionType{CompressionNone, CompressionSnappy, CompressionZstd} {
t.Run(fmt.Sprintf("compress=%s", compress), func(t *testing.T) {
dir := t.TempDir()
wdir := path.Join(dir, "wal")
err := os.Mkdir(wdir, 0o777)
require.NoError(t, err)
enc := record.Encoder{}
w, err := NewSize(nil, nil, wdir, segmentSize, compress)
require.NoError(t, err)
defer func() {
require.NoError(t, w.Close())
}()
// Write to the initial segment then checkpoint.
for i := 0; i < seriesCount; i++ {
ref := i + 100
series := enc.Series([]record.RefSeries{
{
Ref: chunks.HeadSeriesRef(ref),
Labels: labels.FromStrings("__name__", fmt.Sprintf("metric_%d", i)),
},
}, nil)
require.NoError(t, w.Log(series))
// Add in an unknown record type, which should be ignored.
require.NoError(t, w.Log([]byte{255}))
for j := 0; j < samplesCount; j++ {
inner := rand.Intn(ref + 1)
sample := enc.Samples([]record.RefSample{
{
Ref: chunks.HeadSeriesRef(inner),
T: int64(i),
V: float64(i),
},
}, nil)
require.NoError(t, w.Log(sample))
}
}
Checkpoint(promslog.NewNopLogger(), w, 0, 1, func(x chunks.HeadSeriesRef) bool { return true }, 0)
w.Truncate(1)
// Write more records after checkpointing.
for i := 0; i < seriesCount; i++ {
series := enc.Series([]record.RefSeries{
{
Ref: chunks.HeadSeriesRef(i),
Labels: labels.FromStrings("__name__", fmt.Sprintf("metric_%d", i)),
},
}, nil)
require.NoError(t, w.Log(series))
for j := 0; j < samplesCount; j++ {
sample := enc.Samples([]record.RefSample{
{
Ref: chunks.HeadSeriesRef(j),
T: int64(i),
V: float64(i),
},
}, nil)
require.NoError(t, w.Log(sample))
}
}
_, _, err = Segments(w.Dir())
require.NoError(t, err)
overwriteReadTimeout(t, time.Second)
wt := newWriteToMock(0)
watcher := NewWatcher(wMetrics, nil, nil, "", wt, dir, false, false, false)
go watcher.Start()
expected := seriesCount * 2
require.Eventually(t, func() bool {
return wt.checkNumSeries() == expected
}, 10*time.Second, 1*time.Second)
watcher.Stop()
})
}
}
func TestReadCheckpoint(t *testing.T) {
pageSize := 32 * 1024
const seriesCount = 10
const samplesCount = 250
for _, compress := range []CompressionType{CompressionNone, CompressionSnappy, CompressionZstd} {
t.Run(fmt.Sprintf("compress=%s", compress), func(t *testing.T) {
dir := t.TempDir()
wdir := path.Join(dir, "wal")
err := os.Mkdir(wdir, 0o777)
require.NoError(t, err)
f, err := os.Create(SegmentName(wdir, 30))
require.NoError(t, err)
require.NoError(t, f.Close())
enc := record.Encoder{}
w, err := NewSize(nil, nil, wdir, 128*pageSize, compress)
require.NoError(t, err)
t.Cleanup(func() {
require.NoError(t, w.Close())
})
// Write to the initial segment then checkpoint.
for i := 0; i < seriesCount; i++ {
ref := i + 100
series := enc.Series([]record.RefSeries{
{
Ref: chunks.HeadSeriesRef(ref),
Labels: labels.FromStrings("__name__", fmt.Sprintf("metric_%d", i)),
},
}, nil)
require.NoError(t, w.Log(series))
for j := 0; j < samplesCount; j++ {
inner := rand.Intn(ref + 1)
sample := enc.Samples([]record.RefSample{
{
Ref: chunks.HeadSeriesRef(inner),
T: int64(i),
V: float64(i),
},
}, nil)
require.NoError(t, w.Log(sample))
}
}
_, err = w.NextSegmentSync()
require.NoError(t, err)
_, err = Checkpoint(promslog.NewNopLogger(), w, 30, 31, func(x chunks.HeadSeriesRef) bool { return true }, 0)
require.NoError(t, err)
require.NoError(t, w.Truncate(32))
// Start read after checkpoint, no more data written.
_, _, err = Segments(w.Dir())
require.NoError(t, err)
wt := newWriteToMock(0)
watcher := NewWatcher(wMetrics, nil, nil, "", wt, dir, false, false, false)
go watcher.Start()
expectedSeries := seriesCount
retry(t, defaultRetryInterval, defaultRetries, func() bool {
return wt.checkNumSeries() >= expectedSeries
})
watcher.Stop()
require.Equal(t, expectedSeries, wt.checkNumSeries())
})
}
}
func TestReadCheckpointMultipleSegments(t *testing.T) {
pageSize := 32 * 1024
const segments = 1
const seriesCount = 20
const samplesCount = 300
for _, compress := range []CompressionType{CompressionNone, CompressionSnappy, CompressionZstd} {
t.Run(fmt.Sprintf("compress=%s", compress), func(t *testing.T) {
dir := t.TempDir()
wdir := path.Join(dir, "wal")
err := os.Mkdir(wdir, 0o777)
require.NoError(t, err)
enc := record.Encoder{}
w, err := NewSize(nil, nil, wdir, pageSize, compress)
require.NoError(t, err)
// Write a bunch of data.
for i := 0; i < segments; i++ {
for j := 0; j < seriesCount; j++ {
ref := j + (i * 100)
series := enc.Series([]record.RefSeries{
{
Ref: chunks.HeadSeriesRef(ref),
Labels: labels.FromStrings("__name__", fmt.Sprintf("metric_%d", i)),
},
}, nil)
require.NoError(t, w.Log(series))
for k := 0; k < samplesCount; k++ {
inner := rand.Intn(ref + 1)
sample := enc.Samples([]record.RefSample{
{
Ref: chunks.HeadSeriesRef(inner),
T: int64(i),
V: float64(i),
},
}, nil)
require.NoError(t, w.Log(sample))
}
}
}
require.NoError(t, w.Close())
// At this point we should have at least 6 segments, lets create a checkpoint dir of the first 5.
checkpointDir := dir + "/wal/checkpoint.000004"
err = os.Mkdir(checkpointDir, 0o777)
require.NoError(t, err)
for i := 0; i <= 4; i++ {
err := os.Rename(SegmentName(dir+"/wal", i), SegmentName(checkpointDir, i))
require.NoError(t, err)
}
wt := newWriteToMock(0)
watcher := NewWatcher(wMetrics, nil, nil, "", wt, dir, false, false, false)
watcher.MaxSegment = -1
// Set the Watcher's metrics so they're not nil pointers.
watcher.setMetrics()
lastCheckpoint, _, err := LastCheckpoint(watcher.walDir)
require.NoError(t, err)
err = watcher.readCheckpoint(lastCheckpoint, (*Watcher).readSegment)
require.NoError(t, err)
})
}
}
func TestCheckpointSeriesReset(t *testing.T) {
segmentSize := 32 * 1024
// We need something similar to this # of series and samples
// in order to get enough segments for us to checkpoint.
const seriesCount = 20
const samplesCount = 350
testCases := []struct {
compress CompressionType
segments int
}{
{compress: CompressionNone, segments: 14},
{compress: CompressionSnappy, segments: 13},
}
for _, tc := range testCases {
t.Run(fmt.Sprintf("compress=%s", tc.compress), func(t *testing.T) {
dir := t.TempDir()
wdir := path.Join(dir, "wal")
err := os.Mkdir(wdir, 0o777)
require.NoError(t, err)
enc := record.Encoder{}
w, err := NewSize(nil, nil, wdir, segmentSize, tc.compress)
require.NoError(t, err)
defer func() {
require.NoError(t, w.Close())
}()
// Write to the initial segment, then checkpoint later.
for i := 0; i < seriesCount; i++ {
ref := i + 100
series := enc.Series([]record.RefSeries{
{
Ref: chunks.HeadSeriesRef(ref),
Labels: labels.FromStrings("__name__", fmt.Sprintf("metric_%d", i)),
},
}, nil)
require.NoError(t, w.Log(series))
for j := 0; j < samplesCount; j++ {
inner := rand.Intn(ref + 1)
sample := enc.Samples([]record.RefSample{
{
Ref: chunks.HeadSeriesRef(inner),
T: int64(i),
V: float64(i),
},
}, nil)
require.NoError(t, w.Log(sample))
}
}
_, _, err = Segments(w.Dir())
require.NoError(t, err)
overwriteReadTimeout(t, time.Second)
wt := newWriteToMock(0)
watcher := NewWatcher(wMetrics, nil, nil, "", wt, dir, false, false, false)
watcher.MaxSegment = -1
go watcher.Start()
expected := seriesCount
retry(t, defaultRetryInterval, defaultRetries, func() bool {
return wt.checkNumSeries() >= expected
})
require.Eventually(t, func() bool {
return wt.checkNumSeries() == seriesCount
}, 10*time.Second, 1*time.Second)
_, err = Checkpoint(promslog.NewNopLogger(), w, 2, 4, func(x chunks.HeadSeriesRef) bool { return true }, 0)
require.NoError(t, err)
err = w.Truncate(5)
require.NoError(t, err)
_, cpi, err := LastCheckpoint(path.Join(dir, "wal"))
require.NoError(t, err)
err = watcher.garbageCollectSeries(cpi + 1)
require.NoError(t, err)
watcher.Stop()
// If you modify the checkpoint and truncate segment #'s run the test to see how
// many series records you end up with and change the last Equals check accordingly
// or modify the Equals to Assert(len(wt.seriesLabels) < seriesCount*10)
require.Eventually(t, func() bool {
return wt.checkNumSeries() == tc.segments
}, 20*time.Second, 1*time.Second)
})
}
}
func TestRun_StartupTime(t *testing.T) {
const pageSize = 32 * 1024
const segments = 10
const seriesCount = 20
const samplesCount = 300
for _, compress := range []CompressionType{CompressionNone, CompressionSnappy, CompressionZstd} {
t.Run(string(compress), func(t *testing.T) {
dir := t.TempDir()
wdir := path.Join(dir, "wal")
err := os.Mkdir(wdir, 0o777)
require.NoError(t, err)
enc := record.Encoder{}
w, err := NewSize(nil, nil, wdir, pageSize, compress)
require.NoError(t, err)
for i := 0; i < segments; i++ {
for j := 0; j < seriesCount; j++ {
ref := j + (i * 100)
series := enc.Series([]record.RefSeries{
{
Ref: chunks.HeadSeriesRef(ref),
Labels: labels.FromStrings("__name__", fmt.Sprintf("metric_%d", i)),
},
}, nil)
require.NoError(t, w.Log(series))
for k := 0; k < samplesCount; k++ {
inner := rand.Intn(ref + 1)
sample := enc.Samples([]record.RefSample{
{
Ref: chunks.HeadSeriesRef(inner),
T: int64(i),
V: float64(i),
},
}, nil)
require.NoError(t, w.Log(sample))
}
}
}
require.NoError(t, w.Close())
wt := newWriteToMock(0)
watcher := NewWatcher(wMetrics, nil, nil, "", wt, dir, false, false, false)
watcher.MaxSegment = segments
watcher.setMetrics()
startTime := time.Now()
err = watcher.Run()
require.Less(t, time.Since(startTime), readTimeout)
require.NoError(t, err)
})
}
}
func generateWALRecords(w *WL, segment, seriesCount, samplesCount int) error {
enc := record.Encoder{}
for j := 0; j < seriesCount; j++ {
ref := j + (segment * 100)
series := enc.Series([]record.RefSeries{
{
Ref: chunks.HeadSeriesRef(ref),
Labels: labels.FromStrings("__name__", fmt.Sprintf("metric_%d", segment)),
},
}, nil)
if err := w.Log(series); err != nil {
return err
}
for k := 0; k < samplesCount; k++ {
inner := rand.Intn(ref + 1)
sample := enc.Samples([]record.RefSample{
{
Ref: chunks.HeadSeriesRef(inner),
T: int64(segment),
V: float64(segment),
},
}, nil)
if err := w.Log(sample); err != nil {
return err
}
}
}
return nil
}
func TestRun_AvoidNotifyWhenBehind(t *testing.T) {
if runtime.GOOS == "windows" { // Takes a really long time, perhaps because min sleep time is 15ms.
t.SkipNow()
}
const segmentSize = pageSize // Smallest allowed segment size.
const segmentsToWrite = 5
const segmentsToRead = segmentsToWrite - 1
const seriesCount = 10
const samplesCount = 50
for _, compress := range []CompressionType{CompressionNone, CompressionSnappy, CompressionZstd} {
t.Run(string(compress), func(t *testing.T) {
dir := t.TempDir()
wdir := path.Join(dir, "wal")
err := os.Mkdir(wdir, 0o777)
require.NoError(t, err)
w, err := NewSize(nil, nil, wdir, segmentSize, compress)
require.NoError(t, err)
// Write to 00000000, the watcher will read series from it.
require.NoError(t, generateWALRecords(w, 0, seriesCount, samplesCount))
// Create 00000001, the watcher will tail it once started.
w.NextSegment()
// Set up the watcher and run it in the background.
wt := newWriteToMock(time.Millisecond)
watcher := NewWatcher(wMetrics, nil, nil, "", wt, dir, false, false, false)
watcher.setMetrics()
watcher.MaxSegment = segmentsToRead
var g errgroup.Group
g.Go(func() error {
startTime := time.Now()
err = watcher.Run()
if err != nil {
return err
}
// If the watcher was to wait for readTicker to read every new segment, it would need readTimeout * segmentsToRead.
d := time.Since(startTime)
if d > readTimeout {
return fmt.Errorf("watcher ran for %s, it shouldn't rely on readTicker=%s to read the new segments", d, readTimeout)
}
return nil
})
// The watcher went through 00000000 and is tailing the next one.
retry(t, defaultRetryInterval, defaultRetries, func() bool {
return wt.checkNumSeries() == seriesCount
})
// In the meantime, add some new segments in bulk.
// We should end up with segmentsToWrite + 1 segments now.
for i := 1; i < segmentsToWrite; i++ {
require.NoError(t, generateWALRecords(w, i, seriesCount, samplesCount))
w.NextSegment()
}
// Wait for the watcher.
require.NoError(t, g.Wait())
// All series and samples were read.
require.Equal(t, (segmentsToRead+1)*seriesCount, wt.checkNumSeries()) // Series from 00000000 are also read.
require.Equal(t, segmentsToRead*seriesCount*samplesCount, wt.samplesAppended)
require.NoError(t, w.Close())
})
}
}