/
db.go
867 lines (731 loc) · 24.4 KB
/
db.go
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// 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 agent
import (
"context"
"fmt"
"math"
"path/filepath"
"sync"
"time"
"unicode/utf8"
"github.com/go-kit/log"
"github.com/go-kit/log/level"
"github.com/pkg/errors"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/model"
"go.uber.org/atomic"
"github.com/prometheus/prometheus/model/exemplar"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/model/timestamp"
"github.com/prometheus/prometheus/storage"
"github.com/prometheus/prometheus/storage/remote"
"github.com/prometheus/prometheus/tsdb"
"github.com/prometheus/prometheus/tsdb/chunks"
tsdb_errors "github.com/prometheus/prometheus/tsdb/errors"
"github.com/prometheus/prometheus/tsdb/record"
"github.com/prometheus/prometheus/tsdb/tsdbutil"
"github.com/prometheus/prometheus/tsdb/wal"
)
var ErrUnsupported = errors.New("unsupported operation with WAL-only storage")
// Default values for options.
var (
DefaultTruncateFrequency = 2 * time.Hour
DefaultMinWALTime = int64(5 * time.Minute / time.Millisecond)
DefaultMaxWALTime = int64(4 * time.Hour / time.Millisecond)
)
// Options of the WAL storage.
type Options struct {
// Segments (wal files) max size.
// WALSegmentSize <= 0, segment size is default size.
// WALSegmentSize > 0, segment size is WALSegmentSize.
WALSegmentSize int
// WALCompression will turn on Snappy compression for records on the WAL.
WALCompression bool
// StripeSize is the size (power of 2) in entries of the series hash map. Reducing the size will save memory but impact performance.
StripeSize int
// TruncateFrequency determines how frequently to truncate data from the WAL.
TruncateFrequency time.Duration
// Shortest and longest amount of time data can exist in the WAL before being
// deleted.
MinWALTime, MaxWALTime int64
// NoLockfile disables creation and consideration of a lock file.
NoLockfile bool
}
// DefaultOptions used for the WAL storage. They are sane for setups using
// millisecond-precision timestamps.
func DefaultOptions() *Options {
return &Options{
WALSegmentSize: wal.DefaultSegmentSize,
WALCompression: false,
StripeSize: tsdb.DefaultStripeSize,
TruncateFrequency: DefaultTruncateFrequency,
MinWALTime: DefaultMinWALTime,
MaxWALTime: DefaultMaxWALTime,
NoLockfile: false,
}
}
type dbMetrics struct {
r prometheus.Registerer
numActiveSeries prometheus.Gauge
numWALSeriesPendingDeletion prometheus.Gauge
totalAppendedSamples prometheus.Counter
totalAppendedExemplars prometheus.Counter
totalOutOfOrderSamples prometheus.Counter
walTruncateDuration prometheus.Summary
walCorruptionsTotal prometheus.Counter
walTotalReplayDuration prometheus.Gauge
checkpointDeleteFail prometheus.Counter
checkpointDeleteTotal prometheus.Counter
checkpointCreationFail prometheus.Counter
checkpointCreationTotal prometheus.Counter
}
func newDBMetrics(r prometheus.Registerer) *dbMetrics {
m := dbMetrics{r: r}
m.numActiveSeries = prometheus.NewGauge(prometheus.GaugeOpts{
Name: "prometheus_agent_active_series",
Help: "Number of active series being tracked by the WAL storage",
})
m.numWALSeriesPendingDeletion = prometheus.NewGauge(prometheus.GaugeOpts{
Name: "prometheus_agent_deleted_series",
Help: "Number of series pending deletion from the WAL",
})
m.totalAppendedSamples = prometheus.NewCounter(prometheus.CounterOpts{
Name: "prometheus_agent_samples_appended_total",
Help: "Total number of samples appended to the storage",
})
m.totalAppendedExemplars = prometheus.NewCounter(prometheus.CounterOpts{
Name: "prometheus_agent_exemplars_appended_total",
Help: "Total number of exemplars appended to the storage",
})
m.totalOutOfOrderSamples = prometheus.NewCounter(prometheus.CounterOpts{
Name: "prometheus_agent_out_of_order_samples_total",
Help: "Total number of out of order samples ingestion failed attempts.",
})
m.walTruncateDuration = prometheus.NewSummary(prometheus.SummaryOpts{
Name: "prometheus_agent_truncate_duration_seconds",
Help: "Duration of WAL truncation.",
})
m.walCorruptionsTotal = prometheus.NewCounter(prometheus.CounterOpts{
Name: "prometheus_agent_corruptions_total",
Help: "Total number of WAL corruptions.",
})
m.walTotalReplayDuration = prometheus.NewGauge(prometheus.GaugeOpts{
Name: "prometheus_agent_data_replay_duration_seconds",
Help: "Time taken to replay the data on disk.",
})
m.checkpointDeleteFail = prometheus.NewCounter(prometheus.CounterOpts{
Name: "prometheus_agent_checkpoint_deletions_failed_total",
Help: "Total number of checkpoint deletions that failed.",
})
m.checkpointDeleteTotal = prometheus.NewCounter(prometheus.CounterOpts{
Name: "prometheus_agent_checkpoint_deletions_total",
Help: "Total number of checkpoint deletions attempted.",
})
m.checkpointCreationFail = prometheus.NewCounter(prometheus.CounterOpts{
Name: "prometheus_agent_checkpoint_creations_failed_total",
Help: "Total number of checkpoint creations that failed.",
})
m.checkpointCreationTotal = prometheus.NewCounter(prometheus.CounterOpts{
Name: "prometheus_agent_checkpoint_creations_total",
Help: "Total number of checkpoint creations attempted.",
})
if r != nil {
r.MustRegister(
m.numActiveSeries,
m.numWALSeriesPendingDeletion,
m.totalAppendedSamples,
m.totalAppendedExemplars,
m.totalOutOfOrderSamples,
m.walTruncateDuration,
m.walCorruptionsTotal,
m.walTotalReplayDuration,
m.checkpointDeleteFail,
m.checkpointDeleteTotal,
m.checkpointCreationFail,
m.checkpointCreationTotal,
)
}
return &m
}
func (m *dbMetrics) Unregister() {
if m.r == nil {
return
}
cs := []prometheus.Collector{
m.numActiveSeries,
m.numWALSeriesPendingDeletion,
m.totalAppendedSamples,
m.totalAppendedExemplars,
m.totalOutOfOrderSamples,
m.walTruncateDuration,
m.walCorruptionsTotal,
m.walTotalReplayDuration,
m.checkpointDeleteFail,
m.checkpointDeleteTotal,
m.checkpointCreationFail,
m.checkpointCreationTotal,
}
for _, c := range cs {
m.r.Unregister(c)
}
}
// DB represents a WAL-only storage. It implements storage.DB.
type DB struct {
mtx sync.RWMutex
logger log.Logger
opts *Options
rs *remote.Storage
wal *wal.WAL
locker *tsdbutil.DirLocker
appenderPool sync.Pool
bufPool sync.Pool
nextRef *atomic.Uint64
series *stripeSeries
// deleted is a map of (ref IDs that should be deleted from WAL) to (the WAL segment they
// must be kept around to).
deleted map[chunks.HeadSeriesRef]int
donec chan struct{}
stopc chan struct{}
metrics *dbMetrics
}
// Open returns a new agent.DB in the given directory.
func Open(l log.Logger, reg prometheus.Registerer, rs *remote.Storage, dir string, opts *Options) (*DB, error) {
opts = validateOptions(opts)
locker, err := tsdbutil.NewDirLocker(dir, "agent", l, reg)
if err != nil {
return nil, err
}
if !opts.NoLockfile {
if err := locker.Lock(); err != nil {
return nil, err
}
}
// remote_write expects WAL to be stored in a "wal" subdirectory of the main storage.
dir = filepath.Join(dir, "wal")
w, err := wal.NewSize(l, reg, dir, opts.WALSegmentSize, opts.WALCompression)
if err != nil {
return nil, errors.Wrap(err, "creating WAL")
}
db := &DB{
logger: l,
opts: opts,
rs: rs,
wal: w,
locker: locker,
nextRef: atomic.NewUint64(0),
series: newStripeSeries(opts.StripeSize),
deleted: make(map[chunks.HeadSeriesRef]int),
donec: make(chan struct{}),
stopc: make(chan struct{}),
metrics: newDBMetrics(reg),
}
db.bufPool.New = func() interface{} {
return make([]byte, 0, 1024)
}
db.appenderPool.New = func() interface{} {
return &appender{
DB: db,
pendingSeries: make([]record.RefSeries, 0, 100),
pendingSamples: make([]record.RefSample, 0, 100),
pendingExamplars: make([]record.RefExemplar, 0, 10),
}
}
if err := db.replayWAL(); err != nil {
level.Warn(db.logger).Log("msg", "encountered WAL read error, attempting repair", "err", err)
if err := w.Repair(err); err != nil {
return nil, errors.Wrap(err, "repair corrupted WAL")
}
}
go db.run()
return db, nil
}
func validateOptions(opts *Options) *Options {
if opts == nil {
opts = DefaultOptions()
}
if opts.WALSegmentSize <= 0 {
opts.WALSegmentSize = wal.DefaultSegmentSize
}
// Revert Stripesize to DefaultStripsize if Stripsize is either 0 or not a power of 2.
if opts.StripeSize <= 0 || ((opts.StripeSize & (opts.StripeSize - 1)) != 0) {
opts.StripeSize = tsdb.DefaultStripeSize
}
if opts.TruncateFrequency <= 0 {
opts.TruncateFrequency = DefaultTruncateFrequency
}
if opts.MinWALTime <= 0 {
opts.MinWALTime = 0
}
if opts.MaxWALTime <= 0 {
opts.MaxWALTime = DefaultMaxWALTime
}
if t := int64(opts.TruncateFrequency * time.Hour / time.Millisecond); opts.MaxWALTime < t {
opts.MaxWALTime = t
}
return opts
}
func (db *DB) replayWAL() error {
level.Info(db.logger).Log("msg", "replaying WAL, this may take a while", "dir", db.wal.Dir())
start := time.Now()
dir, startFrom, err := wal.LastCheckpoint(db.wal.Dir())
if err != nil && err != record.ErrNotFound {
return errors.Wrap(err, "find last checkpoint")
}
multiRef := map[chunks.HeadSeriesRef]chunks.HeadSeriesRef{}
if err == nil {
sr, err := wal.NewSegmentsReader(dir)
if err != nil {
return errors.Wrap(err, "open checkpoint")
}
defer func() {
if err := sr.Close(); err != nil {
level.Warn(db.logger).Log("msg", "error while closing the wal segments reader", "err", err)
}
}()
// A corrupted checkpoint is a hard error for now and requires user
// intervention. There's likely little data that can be recovered anyway.
if err := db.loadWAL(wal.NewReader(sr), multiRef); err != nil {
return errors.Wrap(err, "backfill checkpoint")
}
startFrom++
level.Info(db.logger).Log("msg", "WAL checkpoint loaded")
}
// Find the last segment.
_, last, err := wal.Segments(db.wal.Dir())
if err != nil {
return errors.Wrap(err, "finding WAL segments")
}
// Backfil segments from the most recent checkpoint onwards.
for i := startFrom; i <= last; i++ {
seg, err := wal.OpenReadSegment(wal.SegmentName(db.wal.Dir(), i))
if err != nil {
return errors.Wrap(err, fmt.Sprintf("open WAL segment: %d", i))
}
sr := wal.NewSegmentBufReader(seg)
err = db.loadWAL(wal.NewReader(sr), multiRef)
if err := sr.Close(); err != nil {
level.Warn(db.logger).Log("msg", "error while closing the wal segments reader", "err", err)
}
if err != nil {
return err
}
level.Info(db.logger).Log("msg", "WAL segment loaded", "segment", i, "maxSegment", last)
}
walReplayDuration := time.Since(start)
db.metrics.walTotalReplayDuration.Set(walReplayDuration.Seconds())
return nil
}
func (db *DB) loadWAL(r *wal.Reader, multiRef map[chunks.HeadSeriesRef]chunks.HeadSeriesRef) (err error) {
var (
dec record.Decoder
lastRef = chunks.HeadSeriesRef(db.nextRef.Load())
decoded = make(chan interface{}, 10)
errCh = make(chan error, 1)
seriesPool = sync.Pool{
New: func() interface{} {
return []record.RefSeries{}
},
}
samplesPool = sync.Pool{
New: func() interface{} {
return []record.RefSample{}
},
}
)
go func() {
defer close(decoded)
var err error
for r.Next() {
rec := r.Record()
switch dec.Type(rec) {
case record.Series:
series := seriesPool.Get().([]record.RefSeries)[:0]
series, err = dec.Series(rec, series)
if err != nil {
errCh <- &wal.CorruptionErr{
Err: errors.Wrap(err, "decode series"),
Segment: r.Segment(),
Offset: r.Offset(),
}
return
}
decoded <- series
case record.Samples:
samples := samplesPool.Get().([]record.RefSample)[:0]
samples, err = dec.Samples(rec, samples)
if err != nil {
errCh <- &wal.CorruptionErr{
Err: errors.Wrap(err, "decode samples"),
Segment: r.Segment(),
Offset: r.Offset(),
}
return
}
decoded <- samples
case record.Tombstones, record.Exemplars:
// We don't care about tombstones or exemplars during replay.
// TODO: If decide to decode exemplars, we should make sure to prepopulate
// stripeSeries.exemplars in the next block by using setLatestExemplar.
continue
default:
errCh <- &wal.CorruptionErr{
Err: errors.Errorf("invalid record type %v", dec.Type(rec)),
Segment: r.Segment(),
Offset: r.Offset(),
}
}
}
}()
var nonExistentSeriesRefs atomic.Uint64
for d := range decoded {
switch v := d.(type) {
case []record.RefSeries:
for _, entry := range v {
// If this is a new series, create it in memory. If we never read in a
// sample for this series, its timestamp will remain at 0 and it will
// be deleted at the next GC.
if db.series.GetByID(entry.Ref) == nil {
series := &memSeries{ref: entry.Ref, lset: entry.Labels, lastTs: 0}
db.series.Set(entry.Labels.Hash(), series)
multiRef[entry.Ref] = series.ref
db.metrics.numActiveSeries.Inc()
if entry.Ref > lastRef {
lastRef = entry.Ref
}
}
}
//nolint:staticcheck
seriesPool.Put(v)
case []record.RefSample:
for _, entry := range v {
// Update the lastTs for the series based
ref, ok := multiRef[entry.Ref]
if !ok {
nonExistentSeriesRefs.Inc()
continue
}
series := db.series.GetByID(ref)
if entry.T > series.lastTs {
series.lastTs = entry.T
}
}
//nolint:staticcheck
samplesPool.Put(v)
default:
panic(fmt.Errorf("unexpected decoded type: %T", d))
}
}
if v := nonExistentSeriesRefs.Load(); v > 0 {
level.Warn(db.logger).Log("msg", "found sample referencing non-existing series", "skipped_series", v)
}
db.nextRef.Store(uint64(lastRef))
select {
case err := <-errCh:
return err
default:
if r.Err() != nil {
return errors.Wrap(r.Err(), "read records")
}
return nil
}
}
func (db *DB) run() {
defer close(db.donec)
Loop:
for {
select {
case <-db.stopc:
break Loop
case <-time.After(db.opts.TruncateFrequency):
// The timestamp ts is used to determine which series are not receiving
// samples and may be deleted from the WAL. Their most recent append
// timestamp is compared to ts, and if that timestamp is older then ts,
// they are considered inactive and may be deleted.
//
// Subtracting a duration from ts will add a buffer for when series are
// considered inactive and safe for deletion.
ts := db.rs.LowestSentTimestamp() - db.opts.MinWALTime
if ts < 0 {
ts = 0
}
// Network issues can prevent the result of getRemoteWriteTimestamp from
// changing. We don't want data in the WAL to grow forever, so we set a cap
// on the maximum age data can be. If our ts is older than this cutoff point,
// we'll shift it forward to start deleting very stale data.
if maxTS := timestamp.FromTime(time.Now()) - db.opts.MaxWALTime; ts < maxTS {
ts = maxTS
}
level.Debug(db.logger).Log("msg", "truncating the WAL", "ts", ts)
if err := db.truncate(ts); err != nil {
level.Warn(db.logger).Log("msg", "failed to truncate WAL", "err", err)
}
}
}
}
func (db *DB) truncate(mint int64) error {
db.mtx.RLock()
defer db.mtx.RUnlock()
start := time.Now()
db.gc(mint)
level.Info(db.logger).Log("msg", "series GC completed", "duration", time.Since(start))
first, last, err := wal.Segments(db.wal.Dir())
if err != nil {
return errors.Wrap(err, "get segment range")
}
// Start a new segment so low ingestion volume instances don't have more WAL
// than needed.
err = db.wal.NextSegment()
if err != nil {
return errors.Wrap(err, "next segment")
}
last-- // Never consider most recent segment for checkpoint
if last < 0 {
return nil // no segments yet
}
// The lower two-thirds of segments should contain mostly obsolete samples.
// If we have less than two segments, it's not worth checkpointing yet.
last = first + (last-first)*2/3
if last <= first {
return nil
}
keep := func(id chunks.HeadSeriesRef) bool {
if db.series.GetByID(id) != nil {
return true
}
seg, ok := db.deleted[id]
return ok && seg >= first
}
db.metrics.checkpointCreationTotal.Inc()
if _, err = wal.Checkpoint(db.logger, db.wal, first, last, keep, mint); err != nil {
db.metrics.checkpointCreationFail.Inc()
if _, ok := errors.Cause(err).(*wal.CorruptionErr); ok {
db.metrics.walCorruptionsTotal.Inc()
}
return errors.Wrap(err, "create checkpoint")
}
if err := db.wal.Truncate(last + 1); err != nil {
// If truncating fails, we'll just try it again at the next checkpoint.
// Leftover segments will still just be ignored in the future if there's a
// checkpoint that supersedes them.
level.Error(db.logger).Log("msg", "truncating segments failed", "err", err)
}
// The checkpoint is written and segments before it are truncated, so we
// no longer need to track deleted series that were being kept around.
for ref, segment := range db.deleted {
if segment < first {
delete(db.deleted, ref)
}
}
db.metrics.checkpointDeleteTotal.Inc()
db.metrics.numWALSeriesPendingDeletion.Set(float64(len(db.deleted)))
if err := wal.DeleteCheckpoints(db.wal.Dir(), last); err != nil {
// Leftover old checkpoints do not cause problems down the line beyond
// occupying disk space. They will just be ignored since a newer checkpoint
// exists.
level.Error(db.logger).Log("msg", "delete old checkpoints", "err", err)
db.metrics.checkpointDeleteFail.Inc()
}
db.metrics.walTruncateDuration.Observe(time.Since(start).Seconds())
level.Info(db.logger).Log("msg", "WAL checkpoint complete", "first", first, "last", last, "duration", time.Since(start))
return nil
}
// gc marks ref IDs that have not received a sample since mint as deleted in
// s.deleted, along with the segment where they originally got deleted.
func (db *DB) gc(mint int64) {
deleted := db.series.GC(mint)
db.metrics.numActiveSeries.Sub(float64(len(deleted)))
_, last, _ := wal.Segments(db.wal.Dir())
// We want to keep series records for any newly deleted series
// until we've passed the last recorded segment. This prevents
// the WAL having samples for series records that no longer exist.
for ref := range deleted {
db.deleted[ref] = last
}
db.metrics.numWALSeriesPendingDeletion.Set(float64(len(db.deleted)))
}
// StartTime implements the Storage interface.
func (db *DB) StartTime() (int64, error) {
return int64(model.Latest), nil
}
// Querier implements the Storage interface.
func (db *DB) Querier(ctx context.Context, mint, maxt int64) (storage.Querier, error) {
return nil, ErrUnsupported
}
// ChunkQuerier implements the Storage interface.
func (db *DB) ChunkQuerier(ctx context.Context, mint, maxt int64) (storage.ChunkQuerier, error) {
return nil, ErrUnsupported
}
// ExemplarQuerier implements the Storage interface.
func (db *DB) ExemplarQuerier(ctx context.Context) (storage.ExemplarQuerier, error) {
return nil, ErrUnsupported
}
// Appender implements storage.Storage.
func (db *DB) Appender(_ context.Context) storage.Appender {
return db.appenderPool.Get().(storage.Appender)
}
// Close implements the Storage interface.
func (db *DB) Close() error {
db.mtx.Lock()
defer db.mtx.Unlock()
close(db.stopc)
<-db.donec
db.metrics.Unregister()
return tsdb_errors.NewMulti(db.locker.Release(), db.wal.Close()).Err()
}
type appender struct {
*DB
pendingSeries []record.RefSeries
pendingSamples []record.RefSample
pendingExamplars []record.RefExemplar
// Pointers to the series referenced by each element of pendingSamples.
// Series lock is not held on elements.
sampleSeries []*memSeries
}
func (a *appender) Append(ref storage.SeriesRef, l labels.Labels, t int64, v float64) (storage.SeriesRef, error) {
// series references and chunk references are identical for agent mode.
headRef := chunks.HeadSeriesRef(ref)
series := a.series.GetByID(headRef)
if series == nil {
// Ensure no empty or duplicate labels have gotten through. This mirrors the
// equivalent validation code in the TSDB's headAppender.
l = l.WithoutEmpty()
if len(l) == 0 {
return 0, errors.Wrap(tsdb.ErrInvalidSample, "empty labelset")
}
if lbl, dup := l.HasDuplicateLabelNames(); dup {
return 0, errors.Wrap(tsdb.ErrInvalidSample, fmt.Sprintf(`label name "%s" is not unique`, lbl))
}
var created bool
series, created = a.getOrCreate(l)
if created {
a.pendingSeries = append(a.pendingSeries, record.RefSeries{
Ref: series.ref,
Labels: l,
})
a.metrics.numActiveSeries.Inc()
}
}
series.Lock()
defer series.Unlock()
if t < series.lastTs {
a.metrics.totalOutOfOrderSamples.Inc()
return 0, storage.ErrOutOfOrderSample
}
// NOTE: always modify pendingSamples and sampleSeries together
a.pendingSamples = append(a.pendingSamples, record.RefSample{
Ref: series.ref,
T: t,
V: v,
})
a.sampleSeries = append(a.sampleSeries, series)
a.metrics.totalAppendedSamples.Inc()
return storage.SeriesRef(series.ref), nil
}
func (a *appender) getOrCreate(l labels.Labels) (series *memSeries, created bool) {
hash := l.Hash()
series = a.series.GetByHash(hash, l)
if series != nil {
return series, false
}
ref := chunks.HeadSeriesRef(a.nextRef.Inc())
series = &memSeries{ref: ref, lset: l, lastTs: math.MinInt64}
a.series.Set(hash, series)
return series, true
}
func (a *appender) AppendExemplar(ref storage.SeriesRef, l labels.Labels, e exemplar.Exemplar) (storage.SeriesRef, error) {
// series references and chunk references are identical for agent mode.
headRef := chunks.HeadSeriesRef(ref)
s := a.series.GetByID(headRef)
if s == nil {
return 0, fmt.Errorf("unknown series ref when trying to add exemplar: %d", ref)
}
// Ensure no empty labels have gotten through.
e.Labels = e.Labels.WithoutEmpty()
if lbl, dup := e.Labels.HasDuplicateLabelNames(); dup {
return 0, errors.Wrap(tsdb.ErrInvalidExemplar, fmt.Sprintf(`label name "%s" is not unique`, lbl))
}
// Exemplar label length does not include chars involved in text rendering such as quotes
// equals sign, or commas. See definition of const ExemplarMaxLabelLength.
labelSetLen := 0
for _, l := range e.Labels {
labelSetLen += utf8.RuneCountInString(l.Name)
labelSetLen += utf8.RuneCountInString(l.Value)
if labelSetLen > exemplar.ExemplarMaxLabelSetLength {
return 0, storage.ErrExemplarLabelLength
}
}
// Check for duplicate vs last stored exemplar for this series, and discard those.
// Otherwise, record the current exemplar as the latest.
// Prometheus' TSDB returns 0 when encountering duplicates, so we do the same here.
prevExemplar := a.series.GetLatestExemplar(s.ref)
if prevExemplar != nil && prevExemplar.Equals(e) {
// Duplicate, don't return an error but don't accept the exemplar.
return 0, nil
}
a.series.SetLatestExemplar(s.ref, &e)
a.pendingExamplars = append(a.pendingExamplars, record.RefExemplar{
Ref: s.ref,
T: e.Ts,
V: e.Value,
Labels: e.Labels,
})
a.metrics.totalAppendedExemplars.Inc()
return storage.SeriesRef(s.ref), nil
}
// Commit submits the collected samples and purges the batch.
func (a *appender) Commit() error {
a.mtx.RLock()
defer a.mtx.RUnlock()
var encoder record.Encoder
buf := a.bufPool.Get().([]byte)
if len(a.pendingSeries) > 0 {
buf = encoder.Series(a.pendingSeries, buf)
if err := a.wal.Log(buf); err != nil {
return err
}
buf = buf[:0]
}
if len(a.pendingSamples) > 0 {
buf = encoder.Samples(a.pendingSamples, buf)
if err := a.wal.Log(buf); err != nil {
return err
}
buf = buf[:0]
}
if len(a.pendingExamplars) > 0 {
buf = encoder.Exemplars(a.pendingExamplars, buf)
if err := a.wal.Log(buf); err != nil {
return err
}
buf = buf[:0]
}
var series *memSeries
for i, s := range a.pendingSamples {
series = a.sampleSeries[i]
if !series.updateTimestamp(s.T) {
a.metrics.totalOutOfOrderSamples.Inc()
}
}
//nolint:staticcheck
a.bufPool.Put(buf)
return a.Rollback()
}
func (a *appender) Rollback() error {
a.pendingSeries = a.pendingSeries[:0]
a.pendingSamples = a.pendingSamples[:0]
a.pendingExamplars = a.pendingExamplars[:0]
a.sampleSeries = a.sampleSeries[:0]
a.appenderPool.Put(a)
return nil
}