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Remote Write: fix checkpoint reading (#5429)

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* Fix ReadCheckpoint to ensure that it actually reads all the contents of
each segment in a checkpoint dir, or returns an error.

Signed-off-by: Callum Styan <callumstyan@gmail.com>
This commit is contained in:
Callum Styan 2019-04-09 02:52:44 -07:00 committed by Brian Brazil
parent f7184978f4
commit c2b88992a3
2 changed files with 104 additions and 50 deletions
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65
storage/remote/wal_watcher.go
View File

@ -216,7 +216,7 @@ func (w *WALWatcher) run() error {
// findSegmentForIndex finds the first segment greater than or equal to index.
func (w *WALWatcher) findSegmentForIndex(index int) (int, error) {
refs, err := w.segments()
refs, err := w.segments(w.walDir)
if err != nil {
return -1, nil
}
@ -231,7 +231,7 @@ func (w *WALWatcher) findSegmentForIndex(index int) (int, error) {
}
func (w *WALWatcher) firstAndLast() (int, int, error) {
refs, err := w.segments()
refs, err := w.segments(w.walDir)
if err != nil {
return -1, -1, nil
}
@ -244,8 +244,8 @@ func (w *WALWatcher) firstAndLast() (int, int, error) {
// Copied from tsdb/wal/wal.go so we do not have to open a WAL.
// Plan is to move WAL watcher to TSDB and dedupe these implementations.
func (w *WALWatcher) segments() ([]int, error) {
files, err := fileutil.ReadDir(w.walDir)
func (w *WALWatcher) segments(dir string) ([]int, error) {
files, err := fileutil.ReadDir(dir)
if err != nil {
return nil, err
}
@ -476,27 +476,34 @@ func (w *WALWatcher) readCheckpoint(checkpointDir string) error {
return errors.Wrap(err, "checkpointNum")
}
sr, err := wal.NewSegmentsReader(checkpointDir)
// Ensure we read the whole contents of every segment in the checkpoint dir.
segs, err := w.segments(checkpointDir)
if err != nil {
return errors.Wrap(err, "NewSegmentsReader")
return errors.Wrap(err, "Unable to get segments checkpoint dir")
}
defer sr.Close()
for _, seg := range segs {
size, err := getSegmentSize(checkpointDir, seg)
if err != nil {
return errors.Wrap(err, "getSegmentSize")
}
size, err := getCheckpointSize(checkpointDir)
if err != nil {
return errors.Wrap(err, "getCheckpointSize")
sr, err := wal.OpenReadSegment(wal.SegmentName(checkpointDir, seg))
if err != nil {
return errors.Wrap(err, "unable to open segment")
}
defer sr.Close()
r := wal.NewLiveReader(w.logger, sr)
if err := w.readSegment(r, index, false); err != io.EOF && err != nil {
return errors.Wrap(err, "readSegment")
}
if r.Offset() != size {
return fmt.Errorf("readCheckpoint wasn't able to read all data from the checkpoint %s/%08d, size: %d, totalRead: %d", checkpointDir, seg, size, r.Offset())
}
}
r := wal.NewLiveReader(w.logger, sr)
if err := w.readSegment(r, index, false); err != io.EOF {
return errors.Wrap(err, "readSegment")
}
if r.Offset() != size {
level.Warn(w.logger).Log("msg", "may not have read all data from checkpoint", "totalRead", r.Offset(), "size", size)
}
level.Debug(w.logger).Log("msg", "read series references from checkpoint", "checkpoint", checkpointDir)
return nil
}
@ -515,26 +522,6 @@ func checkpointNum(dir string) (int, error) {
return result, nil
}
func getCheckpointSize(dir string) (int64, error) {
i := int64(0)
segs, err := fileutil.ReadDir(dir)
if err != nil {
return 0, err
}
for _, fn := range segs {
num, err := strconv.Atoi(fn)
if err != nil {
return i, err
}
sz, err := getSegmentSize(dir, num)
if err != nil {
return i, err
}
i += sz
}
return i, nil
}
// Get size of segment.
func getSegmentSize(dir string, index int) (int64, error) {
i := int64(-1)

89
storage/remote/wal_watcher_test.go
View File

@ -88,7 +88,7 @@ func newWriteToMock() *writeToMock {
}
}
func Test_tail_samples(t *testing.T) {
func TestTailSamples(t *testing.T) {
pageSize := 32 * 1024
const seriesCount = 10
const samplesCount = 250
@ -160,7 +160,7 @@ func Test_tail_samples(t *testing.T) {
testutil.Equals(t, expectedSamples, wt.samplesAppended)
}
func Test_readToEnd_noCheckpoint(t *testing.T) {
func TestReadToEndNoCheckpoint(t *testing.T) {
pageSize := 32 * 1024
const seriesCount = 10
const samplesCount = 250
@ -222,7 +222,7 @@ func Test_readToEnd_noCheckpoint(t *testing.T) {
testutil.Equals(t, expected, wt.checkNumLabels())
}
func Test_readToEnd_withCheckpoint(t *testing.T) {
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.
@ -304,7 +304,7 @@ func Test_readToEnd_withCheckpoint(t *testing.T) {
testutil.Equals(t, expected, wt.checkNumLabels())
}
func Test_readCheckpoint(t *testing.T) {
func TestReadCheckpoint(t *testing.T) {
pageSize := 32 * 1024
const seriesCount = 10
const samplesCount = 250
@ -366,12 +366,77 @@ func Test_readCheckpoint(t *testing.T) {
testutil.Equals(t, expectedSeries, wt.checkNumLabels())
}
func Test_checkpoint_seriesReset(t *testing.T) {
func TestReadCheckpointMultipleSegments(t *testing.T) {
pageSize := 32 * 1024
const segments = 1
const seriesCount = 20
const samplesCount = 300
dir, err := ioutil.TempDir("", "readCheckpoint")
testutil.Ok(t, err)
defer os.RemoveAll(dir)
wdir := path.Join(dir, "wal")
err = os.Mkdir(wdir, 0777)
testutil.Ok(t, err)
enc := tsdb.RecordEncoder{}
w, err := wal.NewSize(nil, nil, wdir, pageSize)
testutil.Ok(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([]tsdb.RefSeries{
tsdb.RefSeries{
Ref: uint64(ref),
Labels: labels.Labels{labels.Label{"__name__", fmt.Sprintf("metric_%d", j)}},
},
}, nil)
testutil.Ok(t, w.Log(series))
for k := 0; k < samplesCount; k++ {
inner := rand.Intn(ref + 1)
sample := enc.Samples([]tsdb.RefSample{
tsdb.RefSample{
Ref: uint64(inner),
T: int64(i),
V: float64(i),
},
}, nil)
testutil.Ok(t, w.Log(sample))
}
}
}
// 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, 0777)
testutil.Ok(t, err)
for i := 0; i <= 4; i++ {
err := os.Rename(wal.SegmentName(dir+"/wal", i), wal.SegmentName(checkpointDir, i))
testutil.Ok(t, err)
}
wt := newWriteToMock()
watcher := NewWALWatcher(nil, "", wt, dir)
watcher.maxSegment = -1
lastCheckpoint, _, err := tsdb.LastCheckpoint(watcher.walDir)
testutil.Ok(t, err)
err = watcher.readCheckpoint(lastCheckpoint)
testutil.Ok(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 = 10
const samplesCount = 250
const seriesCount = 20
const samplesCount = 350
dir, err := ioutil.TempDir("", "seriesReset")
testutil.Ok(t, err)
@ -421,20 +486,22 @@ func Test_checkpoint_seriesReset(t *testing.T) {
retry(t, defaultRetryInterval, defaultRetries, func() bool {
return wt.checkNumLabels() >= expected
})
watcher.Stop()
testutil.Equals(t, seriesCount, wt.checkNumLabels())
_, err = tsdb.Checkpoint(w, 0, 1, func(x uint64) bool { return true }, 0)
_, err = tsdb.Checkpoint(w, 2, 4, func(x uint64) bool { return true }, 0)
testutil.Ok(t, err)
w.Truncate(1)
err = w.Truncate(5)
testutil.Ok(t, err)
_, cpi, err := tsdb.LastCheckpoint(path.Join(dir, "wal"))
testutil.Ok(t, err)
err = watcher.garbageCollectSeries(cpi + 1)
testutil.Ok(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)
testutil.Equals(t, 6, wt.checkNumLabels())
testutil.Equals(t, 14, wt.checkNumLabels())
}