// Copyright 2017 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"
"crypto/rand"
"errors"
"fmt"
"io"
"log/slog"
"os"
"path/filepath"
"slices"
"time"
"github.com/oklog/ulid"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/promslog"
"github.com/prometheus/prometheus/storage"
"github.com/prometheus/prometheus/tsdb/chunkenc"
"github.com/prometheus/prometheus/tsdb/chunks"
tsdb_errors "github.com/prometheus/prometheus/tsdb/errors"
"github.com/prometheus/prometheus/tsdb/fileutil"
"github.com/prometheus/prometheus/tsdb/index"
"github.com/prometheus/prometheus/tsdb/tombstones"
)
// ExponentialBlockRanges returns the time ranges based on the stepSize.
func ExponentialBlockRanges(minSize int64, steps, stepSize int) []int64 {
ranges := make([]int64, 0, steps)
curRange := minSize
for i := 0; i < steps; i++ {
ranges = append(ranges, curRange)
curRange *= int64(stepSize)
}
return ranges
}
// Compactor provides compaction against an underlying storage
// of time series data.
type Compactor interface {
// Plan returns a set of directories that can be compacted concurrently.
// The directories can be overlapping.
// Results returned when compactions are in progress are undefined.
Plan(dir string) ([]string, error)
// Write persists one or more Blocks into a directory.
// No Block is written when resulting Block has 0 samples and returns an empty slice.
// Prometheus always return one or no block. The interface allows returning more than one
// block for downstream users to experiment with compactor.
Write(dest string, b BlockReader, mint, maxt int64, base *BlockMeta) ([]ulid.ULID, error)
// Compact runs compaction against the provided directories. Must
// only be called concurrently with results of Plan().
// Can optionally pass a list of already open blocks,
// to avoid having to reopen them.
// Prometheus always return one or no block. The interface allows returning more than one
// block for downstream users to experiment with compactor.
// When one resulting Block has 0 samples
// * No block is written.
// * The source dirs are marked Deletable.
// * Block is not included in the result.
Compact(dest string, dirs []string, open []*Block) ([]ulid.ULID, error)
}
// LeveledCompactor implements the Compactor interface.
type LeveledCompactor struct {
metrics *CompactorMetrics
logger *slog.Logger
ranges []int64
chunkPool chunkenc.Pool
ctx context.Context
maxBlockChunkSegmentSize int64
mergeFunc storage.VerticalChunkSeriesMergeFunc
postingsEncoder index.PostingsEncoder
postingsDecoderFactory PostingsDecoderFactory
enableOverlappingCompaction bool
}
type CompactorMetrics struct {
Ran prometheus.Counter
PopulatingBlocks prometheus.Gauge
OverlappingBlocks prometheus.Counter
Duration prometheus.Histogram
ChunkSize prometheus.Histogram
ChunkSamples prometheus.Histogram
ChunkRange prometheus.Histogram
}
// NewCompactorMetrics initializes metrics for Compactor.
func NewCompactorMetrics(r prometheus.Registerer) *CompactorMetrics {
m := &CompactorMetrics{}
m.Ran = prometheus.NewCounter(prometheus.CounterOpts{
Name: "prometheus_tsdb_compactions_total",
Help: "Total number of compactions that were executed for the partition.",
})
m.PopulatingBlocks = prometheus.NewGauge(prometheus.GaugeOpts{
Name: "prometheus_tsdb_compaction_populating_block",
Help: "Set to 1 when a block is currently being written to the disk.",
})
m.OverlappingBlocks = prometheus.NewCounter(prometheus.CounterOpts{
Name: "prometheus_tsdb_vertical_compactions_total",
Help: "Total number of compactions done on overlapping blocks.",
})
m.Duration = prometheus.NewHistogram(prometheus.HistogramOpts{
Name: "prometheus_tsdb_compaction_duration_seconds",
Help: "Duration of compaction runs",
Buckets: prometheus.ExponentialBuckets(1, 2, 14),
NativeHistogramBucketFactor: 1.1,
NativeHistogramMaxBucketNumber: 100,
NativeHistogramMinResetDuration: 1 * time.Hour,
})
m.ChunkSize = prometheus.NewHistogram(prometheus.HistogramOpts{
Name: "prometheus_tsdb_compaction_chunk_size_bytes",
Help: "Final size of chunks on their first compaction",
Buckets: prometheus.ExponentialBuckets(32, 1.5, 12),
})
m.ChunkSamples = prometheus.NewHistogram(prometheus.HistogramOpts{
Name: "prometheus_tsdb_compaction_chunk_samples",
Help: "Final number of samples on their first compaction",
Buckets: prometheus.ExponentialBuckets(4, 1.5, 12),
})
m.ChunkRange = prometheus.NewHistogram(prometheus.HistogramOpts{
Name: "prometheus_tsdb_compaction_chunk_range_seconds",
Help: "Final time range of chunks on their first compaction",
Buckets: prometheus.ExponentialBuckets(100, 4, 10),
})
if r != nil {
r.MustRegister(
m.Ran,
m.PopulatingBlocks,
m.OverlappingBlocks,
m.Duration,
m.ChunkRange,
m.ChunkSamples,
m.ChunkSize,
)
}
return m
}
type LeveledCompactorOptions struct {
// PE specifies the postings encoder. It is called when compactor is writing out the postings for a label name/value pair during compaction.
// If it is nil then the default encoder is used. At the moment that is the "raw" encoder. See index.EncodePostingsRaw for more.
PE index.PostingsEncoder
// PD specifies the postings decoder factory to return different postings decoder based on BlockMeta. It is called when opening a block or opening the index file.
// If it is nil then a default decoder is used, compatible with Prometheus v2.
PD PostingsDecoderFactory
// MaxBlockChunkSegmentSize is the max block chunk segment size. If it is 0 then the default chunks.DefaultChunkSegmentSize is used.
MaxBlockChunkSegmentSize int64
// MergeFunc is used for merging series together in vertical compaction. By default storage.NewCompactingChunkSeriesMerger(storage.ChainedSeriesMerge) is used.
MergeFunc storage.VerticalChunkSeriesMergeFunc
// EnableOverlappingCompaction enables compaction of overlapping blocks. In Prometheus it is always enabled.
// It is useful for downstream projects like Mimir, Cortex, Thanos where they have a separate component that does compaction.
EnableOverlappingCompaction bool
}
type PostingsDecoderFactory func(meta *BlockMeta) index.PostingsDecoder
func DefaultPostingsDecoderFactory(_ *BlockMeta) index.PostingsDecoder {
return index.DecodePostingsRaw
}
func NewLeveledCompactorWithChunkSize(ctx context.Context, r prometheus.Registerer, l *slog.Logger, ranges []int64, pool chunkenc.Pool, maxBlockChunkSegmentSize int64, mergeFunc storage.VerticalChunkSeriesMergeFunc) (*LeveledCompactor, error) {
return NewLeveledCompactorWithOptions(ctx, r, l, ranges, pool, LeveledCompactorOptions{
MaxBlockChunkSegmentSize: maxBlockChunkSegmentSize,
MergeFunc: mergeFunc,
EnableOverlappingCompaction: true,
})
}
func NewLeveledCompactor(ctx context.Context, r prometheus.Registerer, l *slog.Logger, ranges []int64, pool chunkenc.Pool, mergeFunc storage.VerticalChunkSeriesMergeFunc) (*LeveledCompactor, error) {
return NewLeveledCompactorWithOptions(ctx, r, l, ranges, pool, LeveledCompactorOptions{
MergeFunc: mergeFunc,
EnableOverlappingCompaction: true,
})
}
func NewLeveledCompactorWithOptions(ctx context.Context, r prometheus.Registerer, l *slog.Logger, ranges []int64, pool chunkenc.Pool, opts LeveledCompactorOptions) (*LeveledCompactor, error) {
if len(ranges) == 0 {
return nil, errors.New("at least one range must be provided")
}
if pool == nil {
pool = chunkenc.NewPool()
}
if l == nil {
l = promslog.NewNopLogger()
}
mergeFunc := opts.MergeFunc
if mergeFunc == nil {
mergeFunc = storage.NewCompactingChunkSeriesMerger(storage.ChainedSeriesMerge)
}
maxBlockChunkSegmentSize := opts.MaxBlockChunkSegmentSize
if maxBlockChunkSegmentSize == 0 {
maxBlockChunkSegmentSize = chunks.DefaultChunkSegmentSize
}
pe := opts.PE
if pe == nil {
pe = index.EncodePostingsRaw
}
return &LeveledCompactor{
ranges: ranges,
chunkPool: pool,
logger: l,
metrics: NewCompactorMetrics(r),
ctx: ctx,
maxBlockChunkSegmentSize: maxBlockChunkSegmentSize,
mergeFunc: mergeFunc,
postingsEncoder: pe,
postingsDecoderFactory: opts.PD,
enableOverlappingCompaction: opts.EnableOverlappingCompaction,
}, nil
}
type dirMeta struct {
dir string
meta *BlockMeta
}
// Plan returns a list of compactable blocks in the provided directory.
func (c *LeveledCompactor) Plan(dir string) ([]string, error) {
dirs, err := blockDirs(dir)
if err != nil {
return nil, err
}
if len(dirs) < 1 {
return nil, nil
}
var dms []dirMeta
for _, dir := range dirs {
meta, _, err := readMetaFile(dir)
if err != nil {
return nil, err
}
dms = append(dms, dirMeta{dir, meta})
}
return c.plan(dms)
}
func (c *LeveledCompactor) plan(dms []dirMeta) ([]string, error) {
slices.SortFunc(dms, func(a, b dirMeta) int {
switch {
case a.meta.MinTime < b.meta.MinTime:
return -1
case a.meta.MinTime > b.meta.MinTime:
return 1
default:
return 0
}
})
res := c.selectOverlappingDirs(dms)
if len(res) > 0 {
return res, nil
}
// No overlapping blocks, do compaction the usual way.
// We do not include a recently created block with max(minTime), so the block which was just created from WAL.
// This gives users a window of a full block size to piece-wise backup new data without having to care about data overlap.
dms = dms[:len(dms)-1]
for _, dm := range c.selectDirs(dms) {
res = append(res, dm.dir)
}
if len(res) > 0 {
return res, nil
}
// Compact any blocks with big enough time range that have >5% tombstones.
for i := len(dms) - 1; i >= 0; i-- {
meta := dms[i].meta
if meta.MaxTime-meta.MinTime < c.ranges[len(c.ranges)/2] {
// If the block is entirely deleted, then we don't care about the block being big enough.
// TODO: This is assuming a single tombstone is for a distinct series, which might not be true.
if meta.Stats.NumTombstones > 0 && meta.Stats.NumTombstones >= meta.Stats.NumSeries {
return []string{dms[i].dir}, nil
}
break
}
if float64(meta.Stats.NumTombstones)/float64(meta.Stats.NumSeries+1) > 0.05 {
return []string{dms[i].dir}, nil
}
}
return nil, nil
}
// selectDirs returns the dir metas that should be compacted into a single new block.
// If only a single block range is configured, the result is always nil.
func (c *LeveledCompactor) selectDirs(ds []dirMeta) []dirMeta {
if len(c.ranges) < 2 || len(ds) < 1 {
return nil
}
highTime := ds[len(ds)-1].meta.MinTime
for _, iv := range c.ranges[1:] {
parts := splitByRange(ds, iv)
if len(parts) == 0 {
continue
}
Outer:
for _, p := range parts {
// Do not select the range if it has a block whose compaction failed.
for _, dm := range p {
if dm.meta.Compaction.Failed {
continue Outer
}
}
mint := p[0].meta.MinTime
maxt := p[len(p)-1].meta.MaxTime
// Pick the range of blocks if it spans the full range (potentially with gaps)
// or is before the most recent block.
// This ensures we don't compact blocks prematurely when another one of the same
// size still fits in the range.
if (maxt-mint == iv || maxt <= highTime) && len(p) > 1 {
return p
}
}
}
return nil
}
// selectOverlappingDirs returns all dirs with overlapping time ranges.
// It expects sorted input by mint and returns the overlapping dirs in the same order as received.
func (c *LeveledCompactor) selectOverlappingDirs(ds []dirMeta) []string {
if !c.enableOverlappingCompaction {
return nil
}
if len(ds) < 2 {
return nil
}
var overlappingDirs []string
globalMaxt := ds[0].meta.MaxTime
for i, d := range ds[1:] {
if d.meta.MinTime < globalMaxt {
if len(overlappingDirs) == 0 { // When it is the first overlap, need to add the last one as well.
overlappingDirs = append(overlappingDirs, ds[i].dir)
}
overlappingDirs = append(overlappingDirs, d.dir)
} else if len(overlappingDirs) > 0 {
break
}
if d.meta.MaxTime > globalMaxt {
globalMaxt = d.meta.MaxTime
}
}
return overlappingDirs
}
// splitByRange splits the directories by the time range. The range sequence starts at 0.
//
// For example, if we have blocks [0-10, 10-20, 50-60, 90-100] and the split range tr is 30
// it returns [0-10, 10-20], [50-60], [90-100].
func splitByRange(ds []dirMeta, tr int64) [][]dirMeta {
var splitDirs [][]dirMeta
for i := 0; i < len(ds); {
var (
group []dirMeta
t0 int64
m = ds[i].meta
)
// Compute start of aligned time range of size tr closest to the current block's start.
if m.MinTime >= 0 {
t0 = tr * (m.MinTime / tr)
} else {
t0 = tr * ((m.MinTime - tr + 1) / tr)
}
// Skip blocks that don't fall into the range. This can happen via mis-alignment or
// by being a multiple of the intended range.
if m.MaxTime > t0+tr {
i++
continue
}
// Add all dirs to the current group that are within [t0, t0+tr].
for ; i < len(ds); i++ {
// Either the block falls into the next range or doesn't fit at all (checked above).
if ds[i].meta.MaxTime > t0+tr {
break
}
group = append(group, ds[i])
}
if len(group) > 0 {
splitDirs = append(splitDirs, group)
}
}
return splitDirs
}
// CompactBlockMetas merges many block metas into one, combining its source blocks together
// and adjusting compaction level. Min/Max time of result block meta covers all input blocks.
func CompactBlockMetas(uid ulid.ULID, blocks ...*BlockMeta) *BlockMeta {
res := &BlockMeta{
ULID: uid,
}
sources := map[ulid.ULID]struct{}{}
mint := blocks[0].MinTime
maxt := blocks[0].MaxTime
for _, b := range blocks {
if b.MinTime < mint {
mint = b.MinTime
}
if b.MaxTime > maxt {
maxt = b.MaxTime
}
if b.Compaction.Level > res.Compaction.Level {
res.Compaction.Level = b.Compaction.Level
}
for _, s := range b.Compaction.Sources {
sources[s] = struct{}{}
}
res.Compaction.Parents = append(res.Compaction.Parents, BlockDesc{
ULID: b.ULID,
MinTime: b.MinTime,
MaxTime: b.MaxTime,
})
}
res.Compaction.Level++
for s := range sources {
res.Compaction.Sources = append(res.Compaction.Sources, s)
}
slices.SortFunc(res.Compaction.Sources, func(a, b ulid.ULID) int {
return a.Compare(b)
})
res.MinTime = mint
res.MaxTime = maxt
return res
}
// Compact creates a new block in the compactor's directory from the blocks in the
// provided directories.
func (c *LeveledCompactor) Compact(dest string, dirs []string, open []*Block) ([]ulid.ULID, error) {
return c.CompactWithBlockPopulator(dest, dirs, open, DefaultBlockPopulator{})
}
func (c *LeveledCompactor) CompactWithBlockPopulator(dest string, dirs []string, open []*Block, blockPopulator BlockPopulator) ([]ulid.ULID, error) {
var (
blocks []BlockReader
bs []*Block
metas []*BlockMeta
uids []string
)
start := time.Now()
for _, d := range dirs {
meta, _, err := readMetaFile(d)
if err != nil {
return nil, err
}
var b *Block
// Use already open blocks if we can, to avoid
// having the index data in memory twice.
for _, o := range open {
if meta.ULID == o.Meta().ULID {
b = o
break
}
}
if b == nil {
var err error
b, err = OpenBlock(c.logger, d, c.chunkPool, c.postingsDecoderFactory)
if err != nil {
return nil, err
}
defer b.Close()
}
metas = append(metas, meta)
blocks = append(blocks, b)
bs = append(bs, b)
uids = append(uids, meta.ULID.String())
}
uid := ulid.MustNew(ulid.Now(), rand.Reader)
meta := CompactBlockMetas(uid, metas...)
err := c.write(dest, meta, blockPopulator, blocks...)
if err == nil {
if meta.Stats.NumSamples == 0 {
for _, b := range bs {
b.meta.Compaction.Deletable = true
n, err := writeMetaFile(c.logger, b.dir, &b.meta)
if err != nil {
c.logger.Error(
"Failed to write 'Deletable' to meta file after compaction",
"ulid", b.meta.ULID,
)
}
b.numBytesMeta = n
}
c.logger.Info(
"compact blocks resulted in empty block",
"count", len(blocks),
"sources", fmt.Sprintf("%v", uids),
"duration", time.Since(start),
)
return nil, nil
}
c.logger.Info(
"compact blocks",
"count", len(blocks),
"mint", meta.MinTime,
"maxt", meta.MaxTime,
"ulid", meta.ULID,
"sources", fmt.Sprintf("%v", uids),
"duration", time.Since(start),
)
return []ulid.ULID{uid}, nil
}
errs := tsdb_errors.NewMulti(err)
if !errors.Is(err, context.Canceled) {
for _, b := range bs {
if err := b.setCompactionFailed(); err != nil {
errs.Add(fmt.Errorf("setting compaction failed for block: %s: %w", b.Dir(), err))
}
}
}
return nil, errs.Err()
}
func (c *LeveledCompactor) Write(dest string, b BlockReader, mint, maxt int64, base *BlockMeta) ([]ulid.ULID, error) {
start := time.Now()
uid := ulid.MustNew(ulid.Now(), rand.Reader)
meta := &BlockMeta{
ULID: uid,
MinTime: mint,
MaxTime: maxt,
}
meta.Compaction.Level = 1
meta.Compaction.Sources = []ulid.ULID{uid}
if base != nil {
meta.Compaction.Parents = []BlockDesc{
{ULID: base.ULID, MinTime: base.MinTime, MaxTime: base.MaxTime},
}
if base.Compaction.FromOutOfOrder() {
meta.Compaction.SetOutOfOrder()
}
}
err := c.write(dest, meta, DefaultBlockPopulator{}, b)
if err != nil {
return nil, err
}
if meta.Stats.NumSamples == 0 {
c.logger.Info(
"write block resulted in empty block",
"mint", meta.MinTime,
"maxt", meta.MaxTime,
"duration", time.Since(start),
)
return nil, nil
}
c.logger.Info(
"write block",
"mint", meta.MinTime,
"maxt", meta.MaxTime,
"ulid", meta.ULID,
"duration", time.Since(start),
"ooo", meta.Compaction.FromOutOfOrder(),
)
return []ulid.ULID{uid}, nil
}
// instrumentedChunkWriter is used for level 1 compactions to record statistics
// about compacted chunks.
type instrumentedChunkWriter struct {
ChunkWriter
size prometheus.Histogram
samples prometheus.Histogram
trange prometheus.Histogram
}
func (w *instrumentedChunkWriter) WriteChunks(chunks ...chunks.Meta) error {
for _, c := range chunks {
w.size.Observe(float64(len(c.Chunk.Bytes())))
w.samples.Observe(float64(c.Chunk.NumSamples()))
w.trange.Observe(float64(c.MaxTime - c.MinTime))
}
return w.ChunkWriter.WriteChunks(chunks...)
}
// write creates a new block that is the union of the provided blocks into dir.
func (c *LeveledCompactor) write(dest string, meta *BlockMeta, blockPopulator BlockPopulator, blocks ...BlockReader) (err error) {
dir := filepath.Join(dest, meta.ULID.String())
tmp := dir + tmpForCreationBlockDirSuffix
var closers []io.Closer
defer func(t time.Time) {
err = tsdb_errors.NewMulti(err, tsdb_errors.CloseAll(closers)).Err()
// RemoveAll returns no error when tmp doesn't exist so it is safe to always run it.
if err := os.RemoveAll(tmp); err != nil {
c.logger.Error("removed tmp folder after failed compaction", "err", err.Error())
}
c.metrics.Ran.Inc()
c.metrics.Duration.Observe(time.Since(t).Seconds())
}(time.Now())
if err = os.RemoveAll(tmp); err != nil {
return err
}
if err = os.MkdirAll(tmp, 0o777); err != nil {
return err
}
// Populate chunk and index files into temporary directory with
// data of all blocks.
var chunkw ChunkWriter
chunkw, err = chunks.NewWriterWithSegSize(chunkDir(tmp), c.maxBlockChunkSegmentSize)
if err != nil {
return fmt.Errorf("open chunk writer: %w", err)
}
closers = append(closers, chunkw)
// Record written chunk sizes on level 1 compactions.
if meta.Compaction.Level == 1 {
chunkw = &instrumentedChunkWriter{
ChunkWriter: chunkw,
size: c.metrics.ChunkSize,
samples: c.metrics.ChunkSamples,
trange: c.metrics.ChunkRange,
}
}
indexw, err := index.NewWriterWithEncoder(c.ctx, filepath.Join(tmp, indexFilename), c.postingsEncoder)
if err != nil {
return fmt.Errorf("open index writer: %w", err)
}
closers = append(closers, indexw)
if err := blockPopulator.PopulateBlock(c.ctx, c.metrics, c.logger, c.chunkPool, c.mergeFunc, blocks, meta, indexw, chunkw, AllSortedPostings); err != nil {
return fmt.Errorf("populate block: %w", err)
}
select {
case <-c.ctx.Done():
return c.ctx.Err()
default:
}
// We are explicitly closing them here to check for error even
// though these are covered under defer. This is because in Windows,
// you cannot delete these unless they are closed and the defer is to
// make sure they are closed if the function exits due to an error above.
errs := tsdb_errors.NewMulti()
for _, w := range closers {
errs.Add(w.Close())
}
closers = closers[:0] // Avoid closing the writers twice in the defer.
if errs.Err() != nil {
return errs.Err()
}
// Populated block is empty, so exit early.
if meta.Stats.NumSamples == 0 {
return nil
}
if _, err = writeMetaFile(c.logger, tmp, meta); err != nil {
return fmt.Errorf("write merged meta: %w", err)
}
// Create an empty tombstones file.
if _, err := tombstones.WriteFile(c.logger, tmp, tombstones.NewMemTombstones()); err != nil {
return fmt.Errorf("write new tombstones file: %w", err)
}
df, err := fileutil.OpenDir(tmp)
if err != nil {
return fmt.Errorf("open temporary block dir: %w", err)
}
defer func() {
if df != nil {
df.Close()
}
}()
if err := df.Sync(); err != nil {
return fmt.Errorf("sync temporary dir file: %w", err)
}
// Close temp dir before rename block dir (for windows platform).
if err = df.Close(); err != nil {
return fmt.Errorf("close temporary dir: %w", err)
}
df = nil
// Block successfully written, make it visible in destination dir by moving it from tmp one.
if err := fileutil.Replace(tmp, dir); err != nil {
return fmt.Errorf("rename block dir: %w", err)
}
return nil
}
type BlockPopulator interface {
PopulateBlock(ctx context.Context, metrics *CompactorMetrics, logger *slog.Logger, chunkPool chunkenc.Pool, mergeFunc storage.VerticalChunkSeriesMergeFunc, blocks []BlockReader, meta *BlockMeta, indexw IndexWriter, chunkw ChunkWriter, postingsFunc IndexReaderPostingsFunc) error
}
// IndexReaderPostingsFunc is a function to get a sorted posting iterator from a given index reader.
type IndexReaderPostingsFunc func(ctx context.Context, reader IndexReader) index.Postings
// AllSortedPostings returns a sorted all posting iterator from the input index reader.
func AllSortedPostings(ctx context.Context, reader IndexReader) index.Postings {
k, v := index.AllPostingsKey()
all, err := reader.Postings(ctx, k, v)
if err != nil {
return index.ErrPostings(err)
}
return reader.SortedPostings(all)
}
type DefaultBlockPopulator struct{}
// PopulateBlock fills the index and chunk writers with new data gathered as the union
// of the provided blocks. It returns meta information for the new block.
// It expects sorted blocks input by mint.
func (c DefaultBlockPopulator) PopulateBlock(ctx context.Context, metrics *CompactorMetrics, logger *slog.Logger, chunkPool chunkenc.Pool, mergeFunc storage.VerticalChunkSeriesMergeFunc, blocks []BlockReader, meta *BlockMeta, indexw IndexWriter, chunkw ChunkWriter, postingsFunc IndexReaderPostingsFunc) (err error) {
if len(blocks) == 0 {
return errors.New("cannot populate block from no readers")
}
var (
sets []storage.ChunkSeriesSet
symbols index.StringIter
closers []io.Closer
overlapping bool
)
defer func() {
errs := tsdb_errors.NewMulti(err)
if cerr := tsdb_errors.CloseAll(closers); cerr != nil {
errs.Add(fmt.Errorf("close: %w", cerr))
}
err = errs.Err()
metrics.PopulatingBlocks.Set(0)
}()
metrics.PopulatingBlocks.Set(1)
globalMaxt := blocks[0].Meta().MaxTime
for i, b := range blocks {
select {
case <-ctx.Done():
return ctx.Err()
default:
}
if !overlapping {
if i > 0 && b.Meta().MinTime < globalMaxt {
metrics.OverlappingBlocks.Inc()
overlapping = true
logger.Info("Found overlapping blocks during compaction", "ulid", meta.ULID)
}
if b.Meta().MaxTime > globalMaxt {
globalMaxt = b.Meta().MaxTime
}
}
indexr, err := b.Index()
if err != nil {
return fmt.Errorf("open index reader for block %+v: %w", b.Meta(), err)
}
closers = append(closers, indexr)
chunkr, err := b.Chunks()
if err != nil {
return fmt.Errorf("open chunk reader for block %+v: %w", b.Meta(), err)
}
closers = append(closers, chunkr)
tombsr, err := b.Tombstones()
if err != nil {
return fmt.Errorf("open tombstone reader for block %+v: %w", b.Meta(), err)
}
closers = append(closers, tombsr)
postings := postingsFunc(ctx, indexr)
// Blocks meta is half open: [min, max), so subtract 1 to ensure we don't hold samples with exact meta.MaxTime timestamp.
sets = append(sets, NewBlockChunkSeriesSet(b.Meta().ULID, indexr, chunkr, tombsr, postings, meta.MinTime, meta.MaxTime-1, false))
syms := indexr.Symbols()
if i == 0 {
symbols = syms
continue
}
symbols = NewMergedStringIter(symbols, syms)
}
for symbols.Next() {
if err := indexw.AddSymbol(symbols.At()); err != nil {
return fmt.Errorf("add symbol: %w", err)
}
}
if err := symbols.Err(); err != nil {
return fmt.Errorf("next symbol: %w", err)
}
var (
ref = storage.SeriesRef(0)
chks []chunks.Meta
chksIter chunks.Iterator
)
set := sets[0]
if len(sets) > 1 {
// Merge series using specified chunk series merger.
// The default one is the compacting series merger.
set = storage.NewMergeChunkSeriesSet(sets, 0, mergeFunc)
}
// Iterate over all sorted chunk series.
for set.Next() {
select {
case <-ctx.Done():
return ctx.Err()
default:
}
s := set.At()
chksIter = s.Iterator(chksIter)
chks = chks[:0]
for chksIter.Next() {
// We are not iterating in a streaming way over chunks as
// it's more efficient to do bulk write for index and
// chunk file purposes.
chks = append(chks, chksIter.At())
}
if err := chksIter.Err(); err != nil {
return fmt.Errorf("chunk iter: %w", err)
}
// Skip series with all deleted chunks.
if len(chks) == 0 {
continue
}
if err := chunkw.WriteChunks(chks...); err != nil {
return fmt.Errorf("write chunks: %w", err)
}
if err := indexw.AddSeries(ref, s.Labels(), chks...); err != nil {
return fmt.Errorf("add series: %w", err)
}
meta.Stats.NumChunks += uint64(len(chks))
meta.Stats.NumSeries++
for _, chk := range chks {
meta.Stats.NumSamples += uint64(chk.Chunk.NumSamples())
}
for _, chk := range chks {
if err := chunkPool.Put(chk.Chunk); err != nil {
return fmt.Errorf("put chunk: %w", err)
}
}
ref++
}
if err := set.Err(); err != nil {
return fmt.Errorf("iterate compaction set: %w", err)
}
return nil
}