prometheus/tsdb/head_append.go

927 lines
29 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 tsdb
import (
"context"
"fmt"
"math"
"github.com/go-kit/log/level"
"github.com/pkg/errors"
"github.com/prometheus/prometheus/model/exemplar"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/model/metadata"
"github.com/prometheus/prometheus/storage"
"github.com/prometheus/prometheus/tsdb/chunkenc"
"github.com/prometheus/prometheus/tsdb/chunks"
"github.com/prometheus/prometheus/tsdb/record"
)
// initAppender is a helper to initialize the time bounds of the head
// upon the first sample it receives.
type initAppender struct {
app storage.Appender
head *Head
}
var _ storage.GetRef = &initAppender{}
func (a *initAppender) Append(ref storage.SeriesRef, lset labels.Labels, t int64, v float64) (storage.SeriesRef, error) {
if a.app != nil {
return a.app.Append(ref, lset, t, v)
}
a.head.initTime(t)
a.app = a.head.appender()
return a.app.Append(ref, lset, t, v)
}
func (a *initAppender) AppendExemplar(ref storage.SeriesRef, l labels.Labels, e exemplar.Exemplar) (storage.SeriesRef, error) {
// Check if exemplar storage is enabled.
if !a.head.opts.EnableExemplarStorage || a.head.opts.MaxExemplars.Load() <= 0 {
return 0, nil
}
if a.app != nil {
return a.app.AppendExemplar(ref, l, e)
}
// We should never reach here given we would call Append before AppendExemplar
// and we probably want to always base head/WAL min time on sample times.
a.head.initTime(e.Ts)
a.app = a.head.appender()
return a.app.AppendExemplar(ref, l, e)
}
func (a *initAppender) UpdateMetadata(ref storage.SeriesRef, l labels.Labels, m metadata.Metadata) (storage.SeriesRef, error) {
if a.app != nil {
return a.app.UpdateMetadata(ref, l, m)
}
a.app = a.head.appender()
return a.app.UpdateMetadata(ref, l, m)
}
// initTime initializes a head with the first timestamp. This only needs to be called
// for a completely fresh head with an empty WAL.
func (h *Head) initTime(t int64) {
if !h.minTime.CompareAndSwap(math.MaxInt64, t) {
return
}
// Ensure that max time is initialized to at least the min time we just set.
// Concurrent appenders may already have set it to a higher value.
h.maxTime.CompareAndSwap(math.MinInt64, t)
}
func (a *initAppender) GetRef(lset labels.Labels) (storage.SeriesRef, labels.Labels) {
if g, ok := a.app.(storage.GetRef); ok {
return g.GetRef(lset)
}
return 0, nil
}
func (a *initAppender) Commit() error {
if a.app == nil {
a.head.metrics.activeAppenders.Dec()
return nil
}
return a.app.Commit()
}
func (a *initAppender) Rollback() error {
if a.app == nil {
a.head.metrics.activeAppenders.Dec()
return nil
}
return a.app.Rollback()
}
// Appender returns a new Appender on the database.
func (h *Head) Appender(_ context.Context) storage.Appender {
h.metrics.activeAppenders.Inc()
// The head cache might not have a starting point yet. The init appender
// picks up the first appended timestamp as the base.
if h.MinTime() == math.MaxInt64 {
return &initAppender{
head: h,
}
}
return h.appender()
}
func (h *Head) appender() *headAppender {
appendID, cleanupAppendIDsBelow := h.iso.newAppendID() // Every appender gets an ID that is cleared upon commit/rollback.
// Allocate the exemplars buffer only if exemplars are enabled.
var exemplarsBuf []exemplarWithSeriesRef
if h.opts.EnableExemplarStorage {
exemplarsBuf = h.getExemplarBuffer()
}
return &headAppender{
head: h,
minValidTime: h.appendableMinValidTime(),
mint: math.MaxInt64,
maxt: math.MinInt64,
headMaxt: h.MaxTime(),
oooTimeWindow: h.opts.OutOfOrderTimeWindow.Load(),
samples: h.getAppendBuffer(),
sampleSeries: h.getSeriesBuffer(),
exemplars: exemplarsBuf,
metadata: h.getMetadataBuffer(),
appendID: appendID,
cleanupAppendIDsBelow: cleanupAppendIDsBelow,
}
}
// appendableMinValidTime returns the minimum valid timestamp for appends,
// such that samples stay ahead of prior blocks and the head compaction window.
func (h *Head) appendableMinValidTime() int64 {
// This boundary ensures that no samples will be added to the compaction window.
// This allows race-free, concurrent appending and compaction.
cwEnd := h.MaxTime() - h.chunkRange.Load()/2
// This boundary ensures that we avoid overlapping timeframes from one block to the next.
// While not necessary for correctness, it means we're not required to use vertical compaction.
minValid := h.minValidTime.Load()
return max(cwEnd, minValid)
}
// AppendableMinValidTime returns the minimum valid time for samples to be appended to the Head.
// Returns false if Head hasn't been initialized yet and the minimum time isn't known yet.
func (h *Head) AppendableMinValidTime() (int64, bool) {
if h.MinTime() == math.MaxInt64 {
return 0, false
}
return h.appendableMinValidTime(), true
}
func max(a, b int64) int64 {
if a > b {
return a
}
return b
}
func (h *Head) getAppendBuffer() []record.RefSample {
b := h.appendPool.Get()
if b == nil {
return make([]record.RefSample, 0, 512)
}
return b.([]record.RefSample)
}
func (h *Head) putAppendBuffer(b []record.RefSample) {
//nolint:staticcheck // Ignore SA6002 safe to ignore and actually fixing it has some performance penalty.
h.appendPool.Put(b[:0])
}
func (h *Head) getExemplarBuffer() []exemplarWithSeriesRef {
b := h.exemplarsPool.Get()
if b == nil {
return make([]exemplarWithSeriesRef, 0, 512)
}
return b.([]exemplarWithSeriesRef)
}
func (h *Head) putExemplarBuffer(b []exemplarWithSeriesRef) {
if b == nil {
return
}
//nolint:staticcheck // Ignore SA6002 safe to ignore and actually fixing it has some performance penalty.
h.exemplarsPool.Put(b[:0])
}
func (h *Head) getMetadataBuffer() []record.RefMetadata {
b := h.metadataPool.Get()
if b == nil {
return make([]record.RefMetadata, 0, 512)
}
return b.([]record.RefMetadata)
}
func (h *Head) putMetadataBuffer(b []record.RefMetadata) {
//nolint:staticcheck // Ignore SA6002 safe to ignore and actually fixing it has some performance penalty.
h.metadataPool.Put(b[:0])
}
func (h *Head) getSeriesBuffer() []*memSeries {
b := h.seriesPool.Get()
if b == nil {
return make([]*memSeries, 0, 512)
}
return b.([]*memSeries)
}
func (h *Head) putSeriesBuffer(b []*memSeries) {
//nolint:staticcheck // Ignore SA6002 safe to ignore and actually fixing it has some performance penalty.
h.seriesPool.Put(b[:0])
}
func (h *Head) getBytesBuffer() []byte {
b := h.bytesPool.Get()
if b == nil {
return make([]byte, 0, 1024)
}
return b.([]byte)
}
func (h *Head) putBytesBuffer(b []byte) {
//nolint:staticcheck // Ignore SA6002 safe to ignore and actually fixing it has some performance penalty.
h.bytesPool.Put(b[:0])
}
type exemplarWithSeriesRef struct {
ref storage.SeriesRef
exemplar exemplar.Exemplar
}
type headAppender struct {
head *Head
minValidTime int64 // No samples below this timestamp are allowed.
mint, maxt int64
headMaxt int64 // We track it here to not take the lock for every sample appended.
oooTimeWindow int64 // Use the same for the entire append, and don't load the atomic for each sample.
series []record.RefSeries // New series held by this appender.
metadata []record.RefMetadata // New metadata held by this appender.
samples []record.RefSample // New samples held by this appender.
exemplars []exemplarWithSeriesRef // New exemplars held by this appender.
sampleSeries []*memSeries // Series corresponding to the samples held by this appender (using corresponding slice indices - same series may appear more than once).
metadataSeries []*memSeries // Series corresponding to the metadata held by this appender.
appendID, cleanupAppendIDsBelow uint64
closed bool
}
func (a *headAppender) Append(ref storage.SeriesRef, lset labels.Labels, t int64, v float64) (storage.SeriesRef, error) {
// For OOO inserts, this restriction is irrelevant and will be checked later once we confirm the sample is an in-order append.
// If OOO inserts are disabled, we may as well as check this as early as we can and avoid more work.
if a.oooTimeWindow == 0 && t < a.minValidTime {
a.head.metrics.outOfBoundSamples.Inc()
return 0, storage.ErrOutOfBounds
}
s := a.head.series.getByID(chunks.HeadSeriesRef(ref))
if s == nil {
// Ensure no empty labels have gotten through.
lset = lset.WithoutEmpty()
if len(lset) == 0 {
return 0, errors.Wrap(ErrInvalidSample, "empty labelset")
}
if l, dup := lset.HasDuplicateLabelNames(); dup {
return 0, errors.Wrap(ErrInvalidSample, fmt.Sprintf(`label name "%s" is not unique`, l))
}
var created bool
var err error
s, created, err = a.head.getOrCreate(lset.Hash(), lset)
if err != nil {
return 0, err
}
if created {
a.series = append(a.series, record.RefSeries{
Ref: s.ref,
Labels: lset,
})
}
}
s.Lock()
// TODO(codesome): If we definitely know at this point that the sample is ooo, then optimise
// to skip that sample from the WAL and write only in the WBL.
_, delta, err := s.appendable(t, v, a.headMaxt, a.minValidTime, a.oooTimeWindow)
if err == nil {
s.pendingCommit = true
}
s.Unlock()
if delta > 0 {
a.head.metrics.oooHistogram.Observe(float64(delta))
}
if err != nil {
switch err {
case storage.ErrOutOfOrderSample:
a.head.metrics.outOfOrderSamples.Inc()
case storage.ErrTooOldSample:
a.head.metrics.tooOldSamples.Inc()
}
return 0, err
}
if t < a.mint {
a.mint = t
}
if t > a.maxt {
a.maxt = t
}
a.samples = append(a.samples, record.RefSample{
Ref: s.ref,
T: t,
V: v,
})
a.sampleSeries = append(a.sampleSeries, s)
return storage.SeriesRef(s.ref), nil
}
// appendable checks whether the given sample is valid for appending to the series. (if we return false and no error)
// The sample belongs to the out of order chunk if we return true and no error.
// An error signifies the sample cannot be handled.
func (s *memSeries) appendable(t int64, v float64, headMaxt, minValidTime, oooTimeWindow int64) (isOOO bool, oooDelta int64, err error) {
// Check if we can append in the in-order chunk.
if t >= minValidTime {
if s.head() == nil {
// The series has no sample and was freshly created.
return false, 0, nil
}
msMaxt := s.maxTime()
if t > msMaxt {
return false, 0, nil
}
if t == msMaxt {
// We are allowing exact duplicates as we can encounter them in valid cases
// like federation and erroring out at that time would be extremely noisy.
// This only checks against the latest in-order sample.
// The OOO headchunk has its own method to detect these duplicates.
if math.Float64bits(s.sampleBuf[3].v) != math.Float64bits(v) {
return false, 0, storage.ErrDuplicateSampleForTimestamp
}
// Sample is identical (ts + value) with most current (highest ts) sample in sampleBuf.
return false, 0, nil
}
}
// The sample cannot go in the in-order chunk. Check if it can go in the out-of-order chunk.
if oooTimeWindow > 0 && t >= headMaxt-oooTimeWindow {
return true, headMaxt - t, nil
}
// The sample cannot go in both in-order and out-of-order chunk.
if oooTimeWindow > 0 {
return true, headMaxt - t, storage.ErrTooOldSample
}
if t < minValidTime {
return false, headMaxt - t, storage.ErrOutOfBounds
}
return false, headMaxt - t, storage.ErrOutOfOrderSample
}
// AppendExemplar for headAppender assumes the series ref already exists, and so it doesn't
// use getOrCreate or make any of the lset sanity checks that Append does.
func (a *headAppender) AppendExemplar(ref storage.SeriesRef, lset labels.Labels, e exemplar.Exemplar) (storage.SeriesRef, error) {
// Check if exemplar storage is enabled.
if !a.head.opts.EnableExemplarStorage || a.head.opts.MaxExemplars.Load() <= 0 {
return 0, nil
}
// Get Series
s := a.head.series.getByID(chunks.HeadSeriesRef(ref))
if s == nil {
s = a.head.series.getByHash(lset.Hash(), lset)
if s != nil {
ref = storage.SeriesRef(s.ref)
}
}
if s == nil {
return 0, fmt.Errorf("unknown HeadSeriesRef when trying to add exemplar: %d", ref)
}
// Ensure no empty labels have gotten through.
e.Labels = e.Labels.WithoutEmpty()
err := a.head.exemplars.ValidateExemplar(s.lset, e)
if err != nil {
if err == storage.ErrDuplicateExemplar || err == storage.ErrExemplarsDisabled {
// Duplicate, don't return an error but don't accept the exemplar.
return 0, nil
}
return 0, err
}
a.exemplars = append(a.exemplars, exemplarWithSeriesRef{ref, e})
return storage.SeriesRef(s.ref), nil
}
// UpdateMetadata for headAppender assumes the series ref already exists, and so it doesn't
// use getOrCreate or make any of the lset sanity checks that Append does.
func (a *headAppender) UpdateMetadata(ref storage.SeriesRef, lset labels.Labels, meta metadata.Metadata) (storage.SeriesRef, error) {
s := a.head.series.getByID(chunks.HeadSeriesRef(ref))
if s == nil {
s = a.head.series.getByHash(lset.Hash(), lset)
if s != nil {
ref = storage.SeriesRef(s.ref)
}
}
if s == nil {
return 0, fmt.Errorf("unknown series when trying to add metadata with HeadSeriesRef: %d and labels: %s", ref, lset)
}
s.RLock()
hasNewMetadata := s.meta == nil || *s.meta != meta
s.RUnlock()
if hasNewMetadata {
a.metadata = append(a.metadata, record.RefMetadata{
Ref: s.ref,
Type: record.GetMetricType(meta.Type),
Unit: meta.Unit,
Help: meta.Help,
})
a.metadataSeries = append(a.metadataSeries, s)
}
return ref, nil
}
var _ storage.GetRef = &headAppender{}
func (a *headAppender) GetRef(lset labels.Labels) (storage.SeriesRef, labels.Labels) {
s := a.head.series.getByHash(lset.Hash(), lset)
if s == nil {
return 0, nil
}
// returned labels must be suitable to pass to Append()
return storage.SeriesRef(s.ref), s.lset
}
// log writes all headAppender's data to the WAL.
func (a *headAppender) log() error {
if a.head.wal == nil {
return nil
}
buf := a.head.getBytesBuffer()
defer func() { a.head.putBytesBuffer(buf) }()
var rec []byte
var enc record.Encoder
if len(a.series) > 0 {
rec = enc.Series(a.series, buf)
buf = rec[:0]
if err := a.head.wal.Log(rec); err != nil {
return errors.Wrap(err, "log series")
}
}
if len(a.metadata) > 0 {
rec = enc.Metadata(a.metadata, buf)
buf = rec[:0]
if err := a.head.wal.Log(rec); err != nil {
return errors.Wrap(err, "log metadata")
}
}
if len(a.samples) > 0 {
rec = enc.Samples(a.samples, buf)
buf = rec[:0]
if err := a.head.wal.Log(rec); err != nil {
return errors.Wrap(err, "log samples")
}
}
if len(a.exemplars) > 0 {
rec = enc.Exemplars(exemplarsForEncoding(a.exemplars), buf)
buf = rec[:0]
if err := a.head.wal.Log(rec); err != nil {
return errors.Wrap(err, "log exemplars")
}
}
return nil
}
func exemplarsForEncoding(es []exemplarWithSeriesRef) []record.RefExemplar {
ret := make([]record.RefExemplar, 0, len(es))
for _, e := range es {
ret = append(ret, record.RefExemplar{
Ref: chunks.HeadSeriesRef(e.ref),
T: e.exemplar.Ts,
V: e.exemplar.Value,
Labels: e.exemplar.Labels,
})
}
return ret
}
// Commit writes to the WAL and adds the data to the Head.
// TODO(codesome): Refactor this method to reduce indentation and make it more readable.
func (a *headAppender) Commit() (err error) {
if a.closed {
return ErrAppenderClosed
}
defer func() { a.closed = true }()
if err := a.log(); err != nil {
_ = a.Rollback() // Most likely the same error will happen again.
return errors.Wrap(err, "write to WAL")
}
// No errors logging to WAL, so pass the exemplars along to the in memory storage.
for _, e := range a.exemplars {
s := a.head.series.getByID(chunks.HeadSeriesRef(e.ref))
// We don't instrument exemplar appends here, all is instrumented by storage.
if err := a.head.exemplars.AddExemplar(s.lset, e.exemplar); err != nil {
if err == storage.ErrOutOfOrderExemplar {
continue
}
level.Debug(a.head.logger).Log("msg", "Unknown error while adding exemplar", "err", err)
}
}
defer a.head.metrics.activeAppenders.Dec()
defer a.head.putAppendBuffer(a.samples)
defer a.head.putSeriesBuffer(a.sampleSeries)
defer a.head.putExemplarBuffer(a.exemplars)
defer a.head.putMetadataBuffer(a.metadata)
defer a.head.iso.closeAppend(a.appendID)
var (
samplesAppended = len(a.samples)
oooAccepted int // number of samples out of order but accepted: with ooo enabled and within time window
oooRejected int // number of samples rejected due to: out of order but OOO support disabled.
tooOldRejected int // number of samples rejected due to: that are out of order but too old (OOO support enabled, but outside time window)
oobRejected int // number of samples rejected due to: out of bounds: with t < minValidTime (OOO support disabled)
inOrderMint int64 = math.MaxInt64
inOrderMaxt int64 = math.MinInt64
ooomint int64 = math.MaxInt64
ooomaxt int64 = math.MinInt64
wblSamples []record.RefSample
oooMmapMarkers map[chunks.HeadSeriesRef]chunks.ChunkDiskMapperRef
oooRecords [][]byte
series *memSeries
enc record.Encoder
)
defer func() {
for i := range oooRecords {
a.head.putBytesBuffer(oooRecords[i][:0])
}
}()
collectOOORecords := func() {
if a.head.wbl == nil {
// WBL is not enabled. So no need to collect.
wblSamples = nil
oooMmapMarkers = nil
return
}
// The m-map happens before adding a new sample. So we collect
// the m-map markers first, and then samples.
// WBL Graphically:
// WBL Before this Commit(): [old samples before this commit for chunk 1]
// WBL After this Commit(): [old samples before this commit for chunk 1][new samples in this commit for chunk 1]mmapmarker1[samples for chunk 2]mmapmarker2[samples for chunk 3]
if oooMmapMarkers != nil {
markers := make([]record.RefMmapMarker, 0, len(oooMmapMarkers))
for ref, mmapRef := range oooMmapMarkers {
markers = append(markers, record.RefMmapMarker{
Ref: ref,
MmapRef: mmapRef,
})
}
r := enc.MmapMarkers(markers, a.head.getBytesBuffer())
oooRecords = append(oooRecords, r)
}
if len(wblSamples) > 0 {
r := enc.Samples(wblSamples, a.head.getBytesBuffer())
oooRecords = append(oooRecords, r)
}
wblSamples = nil
oooMmapMarkers = nil
}
for i, s := range a.samples {
series = a.sampleSeries[i]
series.Lock()
oooSample, _, err := series.appendable(s.T, s.V, a.headMaxt, a.minValidTime, a.oooTimeWindow)
switch err {
case storage.ErrOutOfOrderSample:
samplesAppended--
oooRejected++
case storage.ErrOutOfBounds:
samplesAppended--
oobRejected++
case storage.ErrTooOldSample:
samplesAppended--
tooOldRejected++
case nil:
// Do nothing.
default:
samplesAppended--
}
var ok, chunkCreated bool
if err == nil && oooSample {
// Sample is OOO and OOO handling is enabled
// and the delta is within the OOO tolerance.
var mmapRef chunks.ChunkDiskMapperRef
ok, chunkCreated, mmapRef = series.insert(s.T, s.V, a.head.chunkDiskMapper)
if chunkCreated {
r, ok := oooMmapMarkers[series.ref]
if !ok || r != 0 {
// !ok means there are no markers collected for these samples yet. So we first flush the samples
// before setting this m-map marker.
// r != 0 means we have already m-mapped a chunk for this series in the same Commit().
// Hence, before we m-map again, we should add the samples and m-map markers
// seen till now to the WBL records.
collectOOORecords()
}
if oooMmapMarkers == nil {
oooMmapMarkers = make(map[chunks.HeadSeriesRef]chunks.ChunkDiskMapperRef)
}
oooMmapMarkers[series.ref] = mmapRef
}
if ok {
wblSamples = append(wblSamples, s)
if s.T < ooomint {
ooomint = s.T
}
if s.T > ooomaxt {
ooomaxt = s.T
}
oooAccepted++
} else {
// Sample is an exact duplicate of the last sample.
// NOTE: We can only detect updates if they clash with a sample in the OOOHeadChunk,
// not with samples in already flushed OOO chunks.
// TODO(codesome): Add error reporting? It depends on addressing https://github.com/prometheus/prometheus/discussions/10305.
samplesAppended--
}
} else if err == nil {
ok, chunkCreated = series.append(s.T, s.V, a.appendID, a.head.chunkDiskMapper)
if ok {
if s.T < inOrderMint {
inOrderMint = s.T
}
if s.T > inOrderMaxt {
inOrderMaxt = s.T
}
} else {
// The sample is an exact duplicate, and should be silently dropped.
samplesAppended--
}
}
if chunkCreated {
a.head.metrics.chunks.Inc()
a.head.metrics.chunksCreated.Inc()
}
series.cleanupAppendIDsBelow(a.cleanupAppendIDsBelow)
series.pendingCommit = false
series.Unlock()
}
for i, m := range a.metadata {
series = a.metadataSeries[i]
series.Lock()
series.meta = &metadata.Metadata{Type: record.ToTextparseMetricType(m.Type), Unit: m.Unit, Help: m.Help}
series.Unlock()
}
a.head.metrics.outOfOrderSamples.Add(float64(oooRejected))
a.head.metrics.outOfBoundSamples.Add(float64(oobRejected))
a.head.metrics.tooOldSamples.Add(float64(tooOldRejected))
a.head.metrics.samplesAppended.Add(float64(samplesAppended))
a.head.metrics.outOfOrderSamplesAppended.Add(float64(oooAccepted))
a.head.updateMinMaxTime(inOrderMint, inOrderMaxt)
a.head.updateMinOOOMaxOOOTime(ooomint, ooomaxt)
collectOOORecords()
if a.head.wbl != nil {
if err := a.head.wbl.Log(oooRecords...); err != nil {
// TODO(codesome): Currently WBL logging of ooo samples is best effort here since we cannot try logging
// until we have found what samples become OOO. We can try having a metric for this failure.
// Returning the error here is not correct because we have already put the samples into the memory,
// hence the append/insert was a success.
level.Error(a.head.logger).Log("msg", "Failed to log out of order samples into the WAL", "err", err)
}
}
return nil
}
// insert is like append, except it inserts. Used for OOO samples.
func (s *memSeries) insert(t int64, v float64, chunkDiskMapper *chunks.ChunkDiskMapper) (inserted, chunkCreated bool, mmapRef chunks.ChunkDiskMapperRef) {
c := s.oooHeadChunk
if c == nil || c.chunk.NumSamples() == int(s.oooCapMax) {
// Note: If no new samples come in then we rely on compaction to clean up stale in-memory OOO chunks.
c, mmapRef = s.cutNewOOOHeadChunk(t, chunkDiskMapper)
chunkCreated = true
}
ok := c.chunk.Insert(t, v)
if ok {
if chunkCreated || t < c.minTime {
c.minTime = t
}
if chunkCreated || t > c.maxTime {
c.maxTime = t
}
}
return ok, chunkCreated, mmapRef
}
// append adds the sample (t, v) to the series. The caller also has to provide
// the appendID for isolation. (The appendID can be zero, which results in no
// isolation for this append.)
// It is unsafe to call this concurrently with s.iterator(...) without holding the series lock.
func (s *memSeries) append(t int64, v float64, appendID uint64, chunkDiskMapper *chunks.ChunkDiskMapper) (sampleInOrder, chunkCreated bool) {
// Based on Gorilla white papers this offers near-optimal compression ratio
// so anything bigger that this has diminishing returns and increases
// the time range within which we have to decompress all samples.
const samplesPerChunk = 120
c := s.head()
if c == nil {
if len(s.mmappedChunks) > 0 && s.mmappedChunks[len(s.mmappedChunks)-1].maxTime >= t {
// Out of order sample. Sample timestamp is already in the mmapped chunks, so ignore it.
return false, false
}
// There is no head chunk in this series yet, create the first chunk for the sample.
c = s.cutNewHeadChunk(t, chunkDiskMapper)
chunkCreated = true
}
// Out of order sample.
if c.maxTime >= t {
return false, chunkCreated
}
numSamples := c.chunk.NumSamples()
if numSamples == 0 {
// It could be the new chunk created after reading the chunk snapshot,
// hence we fix the minTime of the chunk here.
c.minTime = t
s.nextAt = rangeForTimestamp(c.minTime, s.chunkRange)
}
// If we reach 25% of a chunk's desired sample count, predict an end time
// for this chunk that will try to make samples equally distributed within
// the remaining chunks in the current chunk range.
// At latest it must happen at the timestamp set when the chunk was cut.
if numSamples == samplesPerChunk/4 {
s.nextAt = computeChunkEndTime(c.minTime, c.maxTime, s.nextAt)
}
// If numSamples > samplesPerChunk*2 then our previous prediction was invalid,
// most likely because samples rate has changed and now they are arriving more frequently.
// Since we assume that the rate is higher, we're being conservative and cutting at 2*samplesPerChunk
// as we expect more chunks to come.
// Note that next chunk will have its nextAt recalculated for the new rate.
if t >= s.nextAt || numSamples >= samplesPerChunk*2 {
c = s.cutNewHeadChunk(t, chunkDiskMapper)
chunkCreated = true
}
s.app.Append(t, v)
c.maxTime = t
s.sampleBuf[0] = s.sampleBuf[1]
s.sampleBuf[1] = s.sampleBuf[2]
s.sampleBuf[2] = s.sampleBuf[3]
s.sampleBuf[3] = sample{t: t, v: v}
if appendID > 0 && s.txs != nil {
s.txs.add(appendID)
}
return true, chunkCreated
}
// computeChunkEndTime estimates the end timestamp based the beginning of a
// chunk, its current timestamp and the upper bound up to which we insert data.
// It assumes that the time range is 1/4 full.
// Assuming that the samples will keep arriving at the same rate, it will make the
// remaining n chunks within this chunk range (before max) equally sized.
func computeChunkEndTime(start, cur, max int64) int64 {
n := (max - start) / ((cur - start + 1) * 4)
if n <= 1 {
return max
}
return start + (max-start)/n
}
func (s *memSeries) cutNewHeadChunk(mint int64, chunkDiskMapper *chunks.ChunkDiskMapper) *memChunk {
s.mmapCurrentHeadChunk(chunkDiskMapper)
s.headChunk = &memChunk{
chunk: chunkenc.NewXORChunk(),
minTime: mint,
maxTime: math.MinInt64,
}
// Set upper bound on when the next chunk must be started. An earlier timestamp
// may be chosen dynamically at a later point.
s.nextAt = rangeForTimestamp(mint, s.chunkRange)
app, err := s.headChunk.chunk.Appender()
if err != nil {
panic(err)
}
s.app = app
return s.headChunk
}
func (s *memSeries) cutNewOOOHeadChunk(mint int64, chunkDiskMapper *chunks.ChunkDiskMapper) (*oooHeadChunk, chunks.ChunkDiskMapperRef) {
ref := s.mmapCurrentOOOHeadChunk(chunkDiskMapper)
s.oooHeadChunk = &oooHeadChunk{
chunk: NewOOOChunk(),
minTime: mint,
maxTime: math.MinInt64,
}
return s.oooHeadChunk, ref
}
func (s *memSeries) mmapCurrentOOOHeadChunk(chunkDiskMapper *chunks.ChunkDiskMapper) chunks.ChunkDiskMapperRef {
if s.oooHeadChunk == nil {
// There is no head chunk, so nothing to m-map here.
return 0
}
xor, _ := s.oooHeadChunk.chunk.ToXOR() // Encode to XorChunk which is more compact and implements all of the needed functionality.
oooXor := &chunkenc.OOOXORChunk{XORChunk: xor}
chunkRef := chunkDiskMapper.WriteChunk(s.ref, s.oooHeadChunk.minTime, s.oooHeadChunk.maxTime, oooXor, handleChunkWriteError)
s.oooMmappedChunks = append(s.oooMmappedChunks, &mmappedChunk{
ref: chunkRef,
numSamples: uint16(xor.NumSamples()),
minTime: s.oooHeadChunk.minTime,
maxTime: s.oooHeadChunk.maxTime,
})
s.oooHeadChunk = nil
return chunkRef
}
func (s *memSeries) mmapCurrentHeadChunk(chunkDiskMapper *chunks.ChunkDiskMapper) {
if s.headChunk == nil {
// There is no head chunk, so nothing to m-map here.
return
}
chunkRef := chunkDiskMapper.WriteChunk(s.ref, s.headChunk.minTime, s.headChunk.maxTime, s.headChunk.chunk, handleChunkWriteError)
s.mmappedChunks = append(s.mmappedChunks, &mmappedChunk{
ref: chunkRef,
numSamples: uint16(s.headChunk.chunk.NumSamples()),
minTime: s.headChunk.minTime,
maxTime: s.headChunk.maxTime,
})
}
func handleChunkWriteError(err error) {
if err != nil && err != chunks.ErrChunkDiskMapperClosed {
panic(err)
}
}
// Rollback removes the samples and exemplars from headAppender and writes any series to WAL.
func (a *headAppender) Rollback() (err error) {
if a.closed {
return ErrAppenderClosed
}
defer func() { a.closed = true }()
defer a.head.metrics.activeAppenders.Dec()
defer a.head.iso.closeAppend(a.appendID)
defer a.head.putSeriesBuffer(a.sampleSeries)
var series *memSeries
for i := range a.samples {
series = a.sampleSeries[i]
series.Lock()
series.cleanupAppendIDsBelow(a.cleanupAppendIDsBelow)
series.pendingCommit = false
series.Unlock()
}
a.head.putAppendBuffer(a.samples)
a.head.putExemplarBuffer(a.exemplars)
a.head.putMetadataBuffer(a.metadata)
a.samples = nil
a.exemplars = nil
a.metadata = nil
// Series are created in the head memory regardless of rollback. Thus we have
// to log them to the WAL in any case.
return a.log()
}