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prometheus/tsdb/index/index.go

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// 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 index
import (
"bufio"
"bytes"
"context"
"encoding/binary"
"fmt"
"hash"
"hash/crc32"
"io"
"math"
"os"
"path/filepath"
"slices"
"sort"
"unsafe"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/storage"
"github.com/prometheus/prometheus/tsdb/chunks"
"github.com/prometheus/prometheus/tsdb/encoding"
tsdb_errors "github.com/prometheus/prometheus/tsdb/errors"
"github.com/prometheus/prometheus/tsdb/fileutil"
)
const (
// MagicIndex 4 bytes at the head of an index file.
MagicIndex = 0xBAAAD700
// HeaderLen represents number of bytes reserved of index for header.
HeaderLen = 5
// FormatV1 represents 1 version of index.
FormatV1 = 1
// FormatV2 represents 2 version of index.
FormatV2 = 2
indexFilename = "index"
seriesByteAlign = 16
)
type indexWriterSeries struct {
labels labels.Labels
chunks []chunks.Meta // series file offset of chunks
}
type indexWriterSeriesSlice []*indexWriterSeries
func (s indexWriterSeriesSlice) Len() int { return len(s) }
func (s indexWriterSeriesSlice) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s indexWriterSeriesSlice) Less(i, j int) bool {
return labels.Compare(s[i].labels, s[j].labels) < 0
}
type indexWriterStage uint8
const (
idxStageNone indexWriterStage = iota
idxStageSymbols
idxStageSeries
idxStageDone
)
func (s indexWriterStage) String() string {
switch s {
case idxStageNone:
return "none"
case idxStageSymbols:
return "symbols"
case idxStageSeries:
return "series"
case idxStageDone:
return "done"
}
return "<unknown>"
}
// The table gets initialized with sync.Once but may still cause a race
// with any other use of the crc32 package anywhere. Thus we initialize it
// before.
var castagnoliTable *crc32.Table
func init() {
castagnoliTable = crc32.MakeTable(crc32.Castagnoli)
}
// newCRC32 initializes a CRC32 hash with a preconfigured polynomial, so the
// polynomial may be easily changed in one location at a later time, if necessary.
func newCRC32() hash.Hash32 {
return crc32.New(castagnoliTable)
}
type symbolCacheEntry struct {
index uint32
lastValueIndex uint32
lastValue string
}
type PostingsEncoder func(*encoding.Encbuf, []uint32) error
// Writer implements the IndexWriter interface for the standard
// serialization format.
type Writer struct {
ctx context.Context
// For the main index file.
f *FileWriter
// Temporary file for postings.
fP *FileWriter
// Temporary file for posting offsets table.
fPO *FileWriter
cntPO uint64
toc TOC
stage indexWriterStage
postingsStart uint64 // Due to padding, can differ from TOC entry.
// Reusable memory.
buf1 encoding.Encbuf
buf2 encoding.Encbuf
numSymbols int
symbols *Symbols
symbolFile *fileutil.MmapFile
lastSymbol string
symbolCache map[string]symbolCacheEntry
labelIndexes []labelIndexHashEntry // Label index offsets.
labelNames map[string]uint64 // Label names, and their usage.
// Hold last series to validate that clients insert new series in order.
lastSeries labels.Labels
lastSeriesRef storage.SeriesRef
// Hold last added chunk reference to make sure that chunks are ordered properly.
lastChunkRef chunks.ChunkRef
crc32 hash.Hash
Version int
postingsEncoder PostingsEncoder
}
// TOC represents index Table Of Content that states where each section of index starts.
type TOC struct {
Symbols uint64
Series uint64
LabelIndices uint64
LabelIndicesTable uint64
Postings uint64
PostingsTable uint64
}
// NewTOCFromByteSlice return parsed TOC from given index byte slice.
func NewTOCFromByteSlice(bs ByteSlice) (*TOC, error) {
if bs.Len() < indexTOCLen {
return nil, encoding.ErrInvalidSize
}
b := bs.Range(bs.Len()-indexTOCLen, bs.Len())
expCRC := binary.BigEndian.Uint32(b[len(b)-4:])
d := encoding.Decbuf{B: b[:len(b)-4]}
if d.Crc32(castagnoliTable) != expCRC {
return nil, fmt.Errorf("read TOC: %w", encoding.ErrInvalidChecksum)
}
toc := &TOC{
Symbols: d.Be64(),
Series: d.Be64(),
LabelIndices: d.Be64(),
LabelIndicesTable: d.Be64(),
Postings: d.Be64(),
PostingsTable: d.Be64(),
}
return toc, d.Err()
}
// NewWriter returns a new Writer to the given filename. It serializes data in format version 2.
// It uses the given encoder to encode each postings list.
func NewWriterWithEncoder(ctx context.Context, fn string, encoder PostingsEncoder) (*Writer, error) {
dir := filepath.Dir(fn)
df, err := fileutil.OpenDir(dir)
if err != nil {
return nil, err
}
defer df.Close() // Close for platform windows.
if err := os.RemoveAll(fn); err != nil {
return nil, fmt.Errorf("remove any existing index at path: %w", err)
}
// Main index file we are building.
f, err := NewFileWriter(fn)
if err != nil {
return nil, err
}
// Temporary file for postings.
fP, err := NewFileWriter(fn + "_tmp_p")
if err != nil {
return nil, err
}
// Temporary file for posting offset table.
fPO, err := NewFileWriter(fn + "_tmp_po")
if err != nil {
return nil, err
}
if err := df.Sync(); err != nil {
return nil, fmt.Errorf("sync dir: %w", err)
}
iw := &Writer{
ctx: ctx,
f: f,
fP: fP,
fPO: fPO,
stage: idxStageNone,
// Reusable memory.
buf1: encoding.Encbuf{B: make([]byte, 0, 1<<22)},
buf2: encoding.Encbuf{B: make([]byte, 0, 1<<22)},
symbolCache: make(map[string]symbolCacheEntry, 1<<8),
labelNames: make(map[string]uint64, 1<<8),
crc32: newCRC32(),
postingsEncoder: encoder,
}
if err := iw.writeMeta(); err != nil {
return nil, err
}
return iw, nil
}
// NewWriter creates a new index writer using the default encoder. See
// NewWriterWithEncoder.
func NewWriter(ctx context.Context, fn string) (*Writer, error) {
return NewWriterWithEncoder(ctx, fn, EncodePostingsRaw)
}
func (w *Writer) write(bufs ...[]byte) error {
return w.f.Write(bufs...)
}
func (w *Writer) writeAt(buf []byte, pos uint64) error {
return w.f.WriteAt(buf, pos)
}
func (w *Writer) addPadding(size int) error {
return w.f.AddPadding(size)
}
type FileWriter struct {
f *os.File
fbuf *bufio.Writer
pos uint64
name string
}
func NewFileWriter(name string) (*FileWriter, error) {
f, err := os.OpenFile(name, os.O_CREATE|os.O_RDWR, 0o666)
if err != nil {
return nil, err
}
return &FileWriter{
f: f,
fbuf: bufio.NewWriterSize(f, 1<<22),
pos: 0,
name: name,
}, nil
}
func (fw *FileWriter) Pos() uint64 {
return fw.pos
}
func (fw *FileWriter) Write(bufs ...[]byte) error {
for _, b := range bufs {
n, err := fw.fbuf.Write(b)
fw.pos += uint64(n)
if err != nil {
return err
}
// For now the index file must not grow beyond 64GiB. Some of the fixed-sized
// offset references in v1 are only 4 bytes large.
// Once we move to compressed/varint representations in those areas, this limitation
// can be lifted.
if fw.pos > 16*math.MaxUint32 {
return fmt.Errorf("%q exceeding max size of 64GiB", fw.name)
}
}
return nil
}
func (fw *FileWriter) Flush() error {
return fw.fbuf.Flush()
}
func (fw *FileWriter) WriteAt(buf []byte, pos uint64) error {
if err := fw.Flush(); err != nil {
return err
}
_, err := fw.f.WriteAt(buf, int64(pos))
return err
}
// AddPadding adds zero byte padding until the file size is a multiple size.
func (fw *FileWriter) AddPadding(size int) error {
p := fw.pos % uint64(size)
if p == 0 {
return nil
}
p = uint64(size) - p
if err := fw.Write(make([]byte, p)); err != nil {
return fmt.Errorf("add padding: %w", err)
}
return nil
}
func (fw *FileWriter) Close() error {
if err := fw.Flush(); err != nil {
return err
}
if err := fw.f.Sync(); err != nil {
return err
}
return fw.f.Close()
}
func (fw *FileWriter) Remove() error {
return os.Remove(fw.name)
}
// ensureStage handles transitions between write stages and ensures that IndexWriter
// methods are called in an order valid for the implementation.
func (w *Writer) ensureStage(s indexWriterStage) error {
select {
case <-w.ctx.Done():
return w.ctx.Err()
default:
}
if w.stage == s {
return nil
}
if w.stage < s-1 {
// A stage has been skipped.
if err := w.ensureStage(s - 1); err != nil {
return err
}
}
if w.stage > s {
return fmt.Errorf("invalid stage %q, currently at %q", s, w.stage)
}
// Mark start of sections in table of contents.
switch s {
case idxStageSymbols:
w.toc.Symbols = w.f.pos
if err := w.startSymbols(); err != nil {
return err
}
case idxStageSeries:
if err := w.finishSymbols(); err != nil {
return err
}
w.toc.Series = w.f.pos
case idxStageDone:
w.toc.LabelIndices = w.f.pos
// LabelIndices generation depends on the posting offset
// table produced at this stage.
if err := w.writePostingsToTmpFiles(); err != nil {
return err
}
if err := w.writeLabelIndices(); err != nil {
return err
}
w.toc.Postings = w.f.pos
if err := w.writePostings(); err != nil {
return err
}
w.toc.LabelIndicesTable = w.f.pos
if err := w.writeLabelIndexesOffsetTable(); err != nil {
return err
}
w.toc.PostingsTable = w.f.pos
if err := w.writePostingsOffsetTable(); err != nil {
return err
}
if err := w.writeTOC(); err != nil {
return err
}
}
w.stage = s
return nil
}
func (w *Writer) writeMeta() error {
w.buf1.Reset()
w.buf1.PutBE32(MagicIndex)
w.buf1.PutByte(FormatV2)
return w.write(w.buf1.Get())
}
// AddSeries adds the series one at a time along with its chunks.
func (w *Writer) AddSeries(ref storage.SeriesRef, lset labels.Labels, chunks ...chunks.Meta) error {
if err := w.ensureStage(idxStageSeries); err != nil {
return err
}
if labels.Compare(lset, w.lastSeries) <= 0 {
return fmt.Errorf("out-of-order series added with label set %q", lset)
}
if ref < w.lastSeriesRef && !w.lastSeries.IsEmpty() {
return fmt.Errorf("series with reference greater than %d already added", ref)
}
lastChunkRef := w.lastChunkRef
lastMaxT := int64(0)
for ix, c := range chunks {
if c.Ref < lastChunkRef {
return fmt.Errorf("unsorted chunk reference: %d, previous: %d", c.Ref, lastChunkRef)
}
lastChunkRef = c.Ref
if ix > 0 && c.MinTime <= lastMaxT {
return fmt.Errorf("chunk minT %d is not higher than previous chunk maxT %d", c.MinTime, lastMaxT)
}
if c.MaxTime < c.MinTime {
return fmt.Errorf("chunk maxT %d is less than minT %d", c.MaxTime, c.MinTime)
}
lastMaxT = c.MaxTime
}
// We add padding to 16 bytes to increase the addressable space we get through 4 byte
// series references.
if err := w.addPadding(seriesByteAlign); err != nil {
return fmt.Errorf("failed to write padding bytes: %w", err)
}
if w.f.pos%seriesByteAlign != 0 {
return fmt.Errorf("series write not 16-byte aligned at %d", w.f.pos)
}
w.buf2.Reset()
w.buf2.PutUvarint(lset.Len())
if err := lset.Validate(func(l labels.Label) error {
var err error
cacheEntry, ok := w.symbolCache[l.Name]
nameIndex := cacheEntry.index
if !ok {
nameIndex, err = w.symbols.ReverseLookup(l.Name)
if err != nil {
return fmt.Errorf("symbol entry for %q does not exist, %w", l.Name, err)
}
}
w.labelNames[l.Name]++
w.buf2.PutUvarint32(nameIndex)
valueIndex := cacheEntry.lastValueIndex
if !ok || cacheEntry.lastValue != l.Value {
valueIndex, err = w.symbols.ReverseLookup(l.Value)
if err != nil {
return fmt.Errorf("symbol entry for %q does not exist, %w", l.Value, err)
}
w.symbolCache[l.Name] = symbolCacheEntry{
index: nameIndex,
lastValueIndex: valueIndex,
lastValue: l.Value,
}
}
w.buf2.PutUvarint32(valueIndex)
return nil
}); err != nil {
return err
}
w.buf2.PutUvarint(len(chunks))
if len(chunks) > 0 {
c := chunks[0]
w.buf2.PutVarint64(c.MinTime)
w.buf2.PutUvarint64(uint64(c.MaxTime - c.MinTime))
w.buf2.PutUvarint64(uint64(c.Ref))
t0 := c.MaxTime
ref0 := int64(c.Ref)
for _, c := range chunks[1:] {
w.buf2.PutUvarint64(uint64(c.MinTime - t0))
w.buf2.PutUvarint64(uint64(c.MaxTime - c.MinTime))
t0 = c.MaxTime
w.buf2.PutVarint64(int64(c.Ref) - ref0)
ref0 = int64(c.Ref)
}
}
w.buf1.Reset()
w.buf1.PutUvarint(w.buf2.Len())
w.buf2.PutHash(w.crc32)
if err := w.write(w.buf1.Get(), w.buf2.Get()); err != nil {
return fmt.Errorf("write series data: %w", err)
}
w.lastSeries.CopyFrom(lset)
w.lastSeriesRef = ref
w.lastChunkRef = lastChunkRef
return nil
}
func (w *Writer) startSymbols() error {
// We are at w.toc.Symbols.
// Leave 4 bytes of space for the length, and another 4 for the number of symbols
// which will both be calculated later.
return w.write([]byte("alenblen"))
}
func (w *Writer) AddSymbol(sym string) error {
if err := w.ensureStage(idxStageSymbols); err != nil {
return err
}
if w.numSymbols != 0 && sym <= w.lastSymbol {
return fmt.Errorf("symbol %q out-of-order", sym)
}
w.lastSymbol = sym
w.numSymbols++
w.buf1.Reset()
w.buf1.PutUvarintStr(sym)
return w.write(w.buf1.Get())
}
func (w *Writer) finishSymbols() error {
symbolTableSize := w.f.pos - w.toc.Symbols - 4
// The symbol table's <len> part is 4 bytes. So the total symbol table size must be less than or equal to 2^32-1
if symbolTableSize > math.MaxUint32 {
return fmt.Errorf("symbol table size exceeds %d bytes: %d", uint32(math.MaxUint32), symbolTableSize)
}
// Write out the length and symbol count.
w.buf1.Reset()
w.buf1.PutBE32int(int(symbolTableSize))
w.buf1.PutBE32int(w.numSymbols)
if err := w.writeAt(w.buf1.Get(), w.toc.Symbols); err != nil {
return err
}
hashPos := w.f.pos
// Leave space for the hash. We can only calculate it
// now that the number of symbols is known, so mmap and do it from there.
if err := w.write([]byte("hash")); err != nil {
return err
}
if err := w.f.Flush(); err != nil {
return err
}
sf, err := fileutil.OpenMmapFile(w.f.name)
if err != nil {
return err
}
w.symbolFile = sf
hash := crc32.Checksum(w.symbolFile.Bytes()[w.toc.Symbols+4:hashPos], castagnoliTable)
w.buf1.Reset()
w.buf1.PutBE32(hash)
if err := w.writeAt(w.buf1.Get(), hashPos); err != nil {
return err
}
// Load in the symbol table efficiently for the rest of the index writing.
w.symbols, err = NewSymbols(realByteSlice(w.symbolFile.Bytes()), FormatV2, int(w.toc.Symbols))
if err != nil {
return fmt.Errorf("read symbols: %w", err)
}
return nil
}
func (w *Writer) writeLabelIndices() error {
if err := w.fPO.Flush(); err != nil {
return err
}
// Find all the label values in the tmp posting offset table.
f, err := fileutil.OpenMmapFile(w.fPO.name)
if err != nil {
return err
}
defer f.Close()
d := encoding.NewDecbufRaw(realByteSlice(f.Bytes()), int(w.fPO.pos))
cnt := w.cntPO
current := []byte{}
values := []uint32{}
for d.Err() == nil && cnt > 0 {
cnt--
d.Uvarint() // Keycount.
name := d.UvarintBytes() // Label name.
value := yoloString(d.UvarintBytes()) // Label value.
d.Uvarint64() // Offset.
if len(name) == 0 {
continue // All index is ignored.
}
if !bytes.Equal(name, current) && len(values) > 0 {
// We've reached a new label name.
if err := w.writeLabelIndex(string(current), values); err != nil {
return err
}
values = values[:0]
}
current = name
sid, err := w.symbols.ReverseLookup(value)
if err != nil {
return err
}
values = append(values, sid)
}
if d.Err() != nil {
return d.Err()
}
// Handle the last label.
if len(values) > 0 {
if err := w.writeLabelIndex(string(current), values); err != nil {
return err
}
}
return nil
}
func (w *Writer) writeLabelIndex(name string, values []uint32) error {
// Align beginning to 4 bytes for more efficient index list scans.
if err := w.addPadding(4); err != nil {
return err
}
w.labelIndexes = append(w.labelIndexes, labelIndexHashEntry{
keys: []string{name},
offset: w.f.pos,
})
startPos := w.f.pos
// Leave 4 bytes of space for the length, which will be calculated later.
if err := w.write([]byte("alen")); err != nil {
return err
}
w.crc32.Reset()
w.buf1.Reset()
w.buf1.PutBE32int(1) // Number of names.
w.buf1.PutBE32int(len(values))
w.buf1.WriteToHash(w.crc32)
if err := w.write(w.buf1.Get()); err != nil {
return err
}
for _, v := range values {
w.buf1.Reset()
w.buf1.PutBE32(v)
w.buf1.WriteToHash(w.crc32)
if err := w.write(w.buf1.Get()); err != nil {
return err
}
}
// Write out the length.
w.buf1.Reset()
l := w.f.pos - startPos - 4
if l > math.MaxUint32 {
return fmt.Errorf("label index size exceeds 4 bytes: %d", l)
}
w.buf1.PutBE32int(int(l))
if err := w.writeAt(w.buf1.Get(), startPos); err != nil {
return err
}
w.buf1.Reset()
w.buf1.PutHashSum(w.crc32)
return w.write(w.buf1.Get())
}
// writeLabelIndexesOffsetTable writes the label indices offset table.
func (w *Writer) writeLabelIndexesOffsetTable() error {
startPos := w.f.pos
// Leave 4 bytes of space for the length, which will be calculated later.
if err := w.write([]byte("alen")); err != nil {
return err
}
w.crc32.Reset()
w.buf1.Reset()
w.buf1.PutBE32int(len(w.labelIndexes))
w.buf1.WriteToHash(w.crc32)
if err := w.write(w.buf1.Get()); err != nil {
return err
}
for _, e := range w.labelIndexes {
w.buf1.Reset()
w.buf1.PutUvarint(len(e.keys))
for _, k := range e.keys {
w.buf1.PutUvarintStr(k)
}
w.buf1.PutUvarint64(e.offset)
w.buf1.WriteToHash(w.crc32)
if err := w.write(w.buf1.Get()); err != nil {
return err
}
}
// Write out the length.
err := w.writeLengthAndHash(startPos)
if err != nil {
return fmt.Errorf("label indexes offset table length/crc32 write error: %w", err)
}
return nil
}
// writePostingsOffsetTable writes the postings offset table.
func (w *Writer) writePostingsOffsetTable() error {
// Ensure everything is in the temporary file.
if err := w.fPO.Flush(); err != nil {
return err
}
startPos := w.f.pos
// Leave 4 bytes of space for the length, which will be calculated later.
if err := w.write([]byte("alen")); err != nil {
return err
}
// Copy over the tmp posting offset table, however we need to
// adjust the offsets.
adjustment := w.postingsStart
w.buf1.Reset()
w.crc32.Reset()
w.buf1.PutBE32int(int(w.cntPO)) // Count.
w.buf1.WriteToHash(w.crc32)
if err := w.write(w.buf1.Get()); err != nil {
return err
}
f, err := fileutil.OpenMmapFile(w.fPO.name)
if err != nil {
return err
}
defer func() {
if f != nil {
f.Close()
}
}()
d := encoding.NewDecbufRaw(realByteSlice(f.Bytes()), int(w.fPO.pos))
cnt := w.cntPO
for d.Err() == nil && cnt > 0 {
w.buf1.Reset()
w.buf1.PutUvarint(d.Uvarint()) // Keycount.
w.buf1.PutUvarintStr(yoloString(d.UvarintBytes())) // Label name.
w.buf1.PutUvarintStr(yoloString(d.UvarintBytes())) // Label value.
w.buf1.PutUvarint64(d.Uvarint64() + adjustment) // Offset.
w.buf1.WriteToHash(w.crc32)
if err := w.write(w.buf1.Get()); err != nil {
return err
}
cnt--
}
if d.Err() != nil {
return d.Err()
}
// Cleanup temporary file.
if err := f.Close(); err != nil {
return err
}
f = nil
if err := w.fPO.Close(); err != nil {
return err
}
if err := w.fPO.Remove(); err != nil {
return err
}
w.fPO = nil
err = w.writeLengthAndHash(startPos)
if err != nil {
return fmt.Errorf("postings offset table length/crc32 write error: %w", err)
}
return nil
}
func (w *Writer) writeLengthAndHash(startPos uint64) error {
w.buf1.Reset()
l := w.f.pos - startPos - 4
if l > math.MaxUint32 {
return fmt.Errorf("length size exceeds 4 bytes: %d", l)
}
w.buf1.PutBE32int(int(l))
if err := w.writeAt(w.buf1.Get(), startPos); err != nil {
return fmt.Errorf("write length from buffer error: %w", err)
}
// Write out the hash.
w.buf1.Reset()
w.buf1.PutHashSum(w.crc32)
if err := w.write(w.buf1.Get()); err != nil {
return fmt.Errorf("write buffer's crc32 error: %w", err)
}
return nil
}
const indexTOCLen = 6*8 + crc32.Size
func (w *Writer) writeTOC() error {
w.buf1.Reset()
w.buf1.PutBE64(w.toc.Symbols)
w.buf1.PutBE64(w.toc.Series)
w.buf1.PutBE64(w.toc.LabelIndices)
w.buf1.PutBE64(w.toc.LabelIndicesTable)
w.buf1.PutBE64(w.toc.Postings)
w.buf1.PutBE64(w.toc.PostingsTable)
w.buf1.PutHash(w.crc32)
return w.write(w.buf1.Get())
}
func (w *Writer) writePostingsToTmpFiles() error {
names := make([]string, 0, len(w.labelNames))
for n := range w.labelNames {
names = append(names, n)
}
slices.Sort(names)
if err := w.f.Flush(); err != nil {
return err
}
f, err := fileutil.OpenMmapFile(w.f.name)
if err != nil {
return err
}
defer f.Close()
// Write out the special all posting.
offsets := []uint32{}
d := encoding.NewDecbufRaw(realByteSlice(f.Bytes()), int(w.toc.LabelIndices))
d.Skip(int(w.toc.Series))
for d.Len() > 0 {
d.ConsumePadding()
startPos := w.toc.LabelIndices - uint64(d.Len())
if startPos%seriesByteAlign != 0 {
return fmt.Errorf("series not 16-byte aligned at %d", startPos)
}
offsets = append(offsets, uint32(startPos/seriesByteAlign))
// Skip to next series.
x := d.Uvarint()
d.Skip(x + crc32.Size)
if err := d.Err(); err != nil {
return err
}
}
if err := w.writePosting("", "", offsets); err != nil {
return err
}
maxPostings := uint64(len(offsets)) // No label name can have more postings than this.
for len(names) > 0 {
batchNames := []string{}
var c uint64
// Try to bunch up label names into one loop, but avoid
// using more memory than a single label name can.
for len(names) > 0 {
if w.labelNames[names[0]]+c > maxPostings {
if c > 0 {
break
}
return fmt.Errorf("corruption detected when writing postings to index: label %q has %d uses, but maxPostings is %d", names[0], w.labelNames[names[0]], maxPostings)
}
batchNames = append(batchNames, names[0])
c += w.labelNames[names[0]]
names = names[1:]
}
nameSymbols := map[uint32]string{}
for _, name := range batchNames {
sid, err := w.symbols.ReverseLookup(name)
if err != nil {
return err
}
nameSymbols[sid] = name
}
// Label name -> label value -> positions.
postings := map[uint32]map[uint32][]uint32{}
d := encoding.NewDecbufRaw(realByteSlice(f.Bytes()), int(w.toc.LabelIndices))
d.Skip(int(w.toc.Series))
for d.Len() > 0 {
d.ConsumePadding()
startPos := w.toc.LabelIndices - uint64(d.Len())
l := d.Uvarint() // Length of this series in bytes.
startLen := d.Len()
// See if label names we want are in the series.
numLabels := d.Uvarint()
for i := 0; i < numLabels; i++ {
lno := uint32(d.Uvarint())
lvo := uint32(d.Uvarint())
if _, ok := nameSymbols[lno]; ok {
if _, ok := postings[lno]; !ok {
postings[lno] = map[uint32][]uint32{}
}
postings[lno][lvo] = append(postings[lno][lvo], uint32(startPos/seriesByteAlign))
}
}
// Skip to next series.
d.Skip(l - (startLen - d.Len()) + crc32.Size)
if err := d.Err(); err != nil {
return err
}
}
for _, name := range batchNames {
// Write out postings for this label name.
sid, err := w.symbols.ReverseLookup(name)
if err != nil {
return err
}
values := make([]uint32, 0, len(postings[sid]))
for v := range postings[sid] {
values = append(values, v)
}
// Symbol numbers are in order, so the strings will also be in order.
slices.Sort(values)
for _, v := range values {
value, err := w.symbols.Lookup(v)
if err != nil {
return err
}
if err := w.writePosting(name, value, postings[sid][v]); err != nil {
return err
}
}
}
select {
case <-w.ctx.Done():
return w.ctx.Err()
default:
}
}
return nil
}
// EncodePostingsRaw uses the "basic" postings list encoding format with no compression:
// <BE uint32 len X><BE uint32 0><BE uint32 1>...<BE uint32 X-1>.
func EncodePostingsRaw(e *encoding.Encbuf, offs []uint32) error {
e.PutBE32int(len(offs))
for _, off := range offs {
if off > (1<<32)-1 {
return fmt.Errorf("series offset %d exceeds 4 bytes", off)
}
e.PutBE32(off)
}
return nil
}
func (w *Writer) writePosting(name, value string, offs []uint32) error {
// Align beginning to 4 bytes for more efficient postings list scans.
if err := w.fP.AddPadding(4); err != nil {
return err
}
// Write out postings offset table to temporary file as we go.
w.buf1.Reset()
w.buf1.PutUvarint(2)
w.buf1.PutUvarintStr(name)
w.buf1.PutUvarintStr(value)
w.buf1.PutUvarint64(w.fP.pos) // This is relative to the postings tmp file, not the final index file.
if err := w.fPO.Write(w.buf1.Get()); err != nil {
return err
}
w.cntPO++
w.buf1.Reset()
if err := w.postingsEncoder(&w.buf1, offs); err != nil {
return err
}
w.buf2.Reset()
l := w.buf1.Len()
// We convert to uint to make code compile on 32-bit systems, as math.MaxUint32 doesn't fit into int there.
if uint(l) > math.MaxUint32 {
return fmt.Errorf("posting size exceeds 4 bytes: %d", l)
}
w.buf2.PutBE32int(l)
w.buf1.PutHash(w.crc32)
return w.fP.Write(w.buf2.Get(), w.buf1.Get())
}
func (w *Writer) writePostings() error {
// There's padding in the tmp file, make sure it actually works.
if err := w.f.AddPadding(4); err != nil {
return err
}
w.postingsStart = w.f.pos
// Copy temporary file into main index.
if err := w.fP.Flush(); err != nil {
return err
}
if _, err := w.fP.f.Seek(0, 0); err != nil {
return err
}
// Don't need to calculate a checksum, so can copy directly.
n, err := io.CopyBuffer(w.f.fbuf, w.fP.f, make([]byte, 1<<20))
if err != nil {
return err
}
if uint64(n) != w.fP.pos {
return fmt.Errorf("wrote %d bytes to posting temporary file, but only read back %d", w.fP.pos, n)
}
w.f.pos += uint64(n)
if err := w.fP.Close(); err != nil {
return err
}
if err := w.fP.Remove(); err != nil {
return err
}
w.fP = nil
return nil
}
type labelIndexHashEntry struct {
keys []string
offset uint64
}
func (w *Writer) Close() error {
// Even if this fails, we need to close all the files.
ensureErr := w.ensureStage(idxStageDone)
if w.symbolFile != nil {
if err := w.symbolFile.Close(); err != nil {
return err
}
}
if w.fP != nil {
if err := w.fP.Close(); err != nil {
return err
}
}
if w.fPO != nil {
if err := w.fPO.Close(); err != nil {
return err
}
}
if err := w.f.Close(); err != nil {
return err
}
return ensureErr
}
// StringIter iterates over a sorted list of strings.
type StringIter interface {
// Next advances the iterator and returns true if another value was found.
Next() bool
// At returns the value at the current iterator position.
At() string
// Err returns the last error of the iterator.
Err() error
}
type Reader struct {
b ByteSlice
toc *TOC
// Close that releases the underlying resources of the byte slice.
c io.Closer
// Map of LabelName to a list of some LabelValues's position in the offset table.
// The first and last values for each name are always present.
postings map[string][]postingOffset
// For the v1 format, labelname -> labelvalue -> offset.
postingsV1 map[string]map[string]uint64
symbols *Symbols
nameSymbols map[uint32]string // Cache of the label name symbol lookups,
// as there are not many and they are half of all lookups.
st *labels.SymbolTable // TODO: see if we can merge this with nameSymbols.
dec *Decoder
version int
}
type postingOffset struct {
value string
off int
}
// ByteSlice abstracts a byte slice.
type ByteSlice interface {
Len() int
Range(start, end int) []byte
}
type realByteSlice []byte
func (b realByteSlice) Len() int {
return len(b)
}
func (b realByteSlice) Range(start, end int) []byte {
return b[start:end]
}
func (b realByteSlice) Sub(start, end int) ByteSlice {
return b[start:end]
}
// NewReader returns a new index reader on the given byte slice. It automatically
// handles different format versions.
func NewReader(b ByteSlice) (*Reader, error) {
return newReader(b, io.NopCloser(nil))
}
// NewFileReader returns a new index reader against the given index file.
func NewFileReader(path string) (*Reader, error) {
f, err := fileutil.OpenMmapFile(path)
if err != nil {
return nil, err
}
r, err := newReader(realByteSlice(f.Bytes()), f)
if err != nil {
return nil, tsdb_errors.NewMulti(
err,
f.Close(),
).Err()
}
return r, nil
}
func newReader(b ByteSlice, c io.Closer) (*Reader, error) {
r := &Reader{
b: b,
c: c,
postings: map[string][]postingOffset{},
st: labels.NewSymbolTable(),
}
// Verify header.
if r.b.Len() < HeaderLen {
return nil, fmt.Errorf("index header: %w", encoding.ErrInvalidSize)
}
if m := binary.BigEndian.Uint32(r.b.Range(0, 4)); m != MagicIndex {
return nil, fmt.Errorf("invalid magic number %x", m)
}
r.version = int(r.b.Range(4, 5)[0])
if r.version != FormatV1 && r.version != FormatV2 {
return nil, fmt.Errorf("unknown index file version %d", r.version)
}
var err error
r.toc, err = NewTOCFromByteSlice(b)
if err != nil {
return nil, fmt.Errorf("read TOC: %w", err)
}
r.symbols, err = NewSymbols(r.b, r.version, int(r.toc.Symbols))
if err != nil {
return nil, fmt.Errorf("read symbols: %w", err)
}
if r.version == FormatV1 {
// Earlier V1 formats don't have a sorted postings offset table, so
// load the whole offset table into memory.
r.postingsV1 = map[string]map[string]uint64{}
if err := ReadPostingsOffsetTable(r.b, r.toc.PostingsTable, func(name, value []byte, off uint64, _ int) error {
if _, ok := r.postingsV1[string(name)]; !ok {
r.postingsV1[string(name)] = map[string]uint64{}
r.postings[string(name)] = nil // Used to get a list of labelnames in places.
}
r.postingsV1[string(name)][string(value)] = off
return nil
}); err != nil {
return nil, fmt.Errorf("read postings table: %w", err)
}
} else {
var lastName, lastValue []byte
lastOff := 0
valueCount := 0
// For the postings offset table we keep every label name but only every nth
// label value (plus the first and last one), to save memory.
if err := ReadPostingsOffsetTable(r.b, r.toc.PostingsTable, func(name, value []byte, _ uint64, off int) error {
if _, ok := r.postings[string(name)]; !ok {
// Next label name.
r.postings[string(name)] = []postingOffset{}
if lastName != nil {
// Always include last value for each label name.
r.postings[string(lastName)] = append(r.postings[string(lastName)], postingOffset{value: string(lastValue), off: lastOff})
}
valueCount = 0
}
if valueCount%symbolFactor == 0 {
r.postings[string(name)] = append(r.postings[string(name)], postingOffset{value: string(value), off: off})
lastName, lastValue = nil, nil
} else {
lastName, lastValue = name, value
lastOff = off
}
valueCount++
return nil
}); err != nil {
return nil, fmt.Errorf("read postings table: %w", err)
}
if lastName != nil {
r.postings[string(lastName)] = append(r.postings[string(lastName)], postingOffset{value: string(lastValue), off: lastOff})
}
// Trim any extra space in the slices.
for k, v := range r.postings {
l := make([]postingOffset, len(v))
copy(l, v)
r.postings[k] = l
}
}
r.nameSymbols = make(map[uint32]string, len(r.postings))
for k := range r.postings {
if k == "" {
continue
}
off, err := r.symbols.ReverseLookup(k)
if err != nil {
return nil, fmt.Errorf("reverse symbol lookup: %w", err)
}
r.nameSymbols[off] = k
}
r.dec = &Decoder{LookupSymbol: r.lookupSymbol}
return r, nil
}
// Version returns the file format version of the underlying index.
func (r *Reader) Version() int {
return r.version
}
// Range marks a byte range.
type Range struct {
Start, End int64
}
// PostingsRanges returns a new map of byte range in the underlying index file
// for all postings lists.
func (r *Reader) PostingsRanges() (map[labels.Label]Range, error) {
m := map[labels.Label]Range{}
if err := ReadPostingsOffsetTable(r.b, r.toc.PostingsTable, func(name, value []byte, off uint64, _ int) error {
d := encoding.NewDecbufAt(r.b, int(off), castagnoliTable)
if d.Err() != nil {
return d.Err()
}
m[labels.Label{Name: string(name), Value: string(value)}] = Range{
Start: int64(off) + 4,
End: int64(off) + 4 + int64(d.Len()),
}
return nil
}); err != nil {
return nil, fmt.Errorf("read postings table: %w", err)
}
return m, nil
}
type Symbols struct {
bs ByteSlice
version int
off int
offsets []int
seen int
}
const symbolFactor = 32
// NewSymbols returns a Symbols object for symbol lookups.
func NewSymbols(bs ByteSlice, version, off int) (*Symbols, error) {
s := &Symbols{
bs: bs,
version: version,
off: off,
}
d := encoding.NewDecbufAt(bs, off, castagnoliTable)
var (
origLen = d.Len()
cnt = d.Be32int()
basePos = off + 4
)
s.offsets = make([]int, 0, 1+cnt/symbolFactor)
for d.Err() == nil && s.seen < cnt {
if s.seen%symbolFactor == 0 {
s.offsets = append(s.offsets, basePos+origLen-d.Len())
}
d.UvarintBytes() // The symbol.
s.seen++
}
if d.Err() != nil {
return nil, d.Err()
}
return s, nil
}
func (s Symbols) Lookup(o uint32) (string, error) {
d := encoding.Decbuf{
B: s.bs.Range(0, s.bs.Len()),
}
if s.version == FormatV2 {
if int(o) >= s.seen {
return "", fmt.Errorf("unknown symbol offset %d", o)
}
d.Skip(s.offsets[int(o/symbolFactor)])
// Walk until we find the one we want.
for i := o - (o / symbolFactor * symbolFactor); i > 0; i-- {
d.UvarintBytes()
}
} else {
d.Skip(int(o))
}
sym := d.UvarintStr()
if d.Err() != nil {
return "", d.Err()
}
return sym, nil
}
func (s Symbols) ReverseLookup(sym string) (uint32, error) {
if len(s.offsets) == 0 {
return 0, fmt.Errorf("unknown symbol %q - no symbols", sym)
}
i := sort.Search(len(s.offsets), func(i int) bool {
// Any decoding errors here will be lost, however
// we already read through all of this at startup.
d := encoding.Decbuf{
B: s.bs.Range(0, s.bs.Len()),
}
d.Skip(s.offsets[i])
return yoloString(d.UvarintBytes()) > sym
})
d := encoding.Decbuf{
B: s.bs.Range(0, s.bs.Len()),
}
if i > 0 {
i--
}
d.Skip(s.offsets[i])
res := i * symbolFactor
var lastLen int
var lastSymbol string
for d.Err() == nil && res <= s.seen {
lastLen = d.Len()
lastSymbol = yoloString(d.UvarintBytes())
if lastSymbol >= sym {
break
}
res++
}
if d.Err() != nil {
return 0, d.Err()
}
if lastSymbol != sym {
return 0, fmt.Errorf("unknown symbol %q", sym)
}
if s.version == FormatV2 {
return uint32(res), nil
}
return uint32(s.bs.Len() - lastLen), nil
}
func (s Symbols) Size() int {
return len(s.offsets) * 8
}
func (s Symbols) Iter() StringIter {
d := encoding.NewDecbufAt(s.bs, s.off, castagnoliTable)
cnt := d.Be32int()
return &symbolsIter{
d: d,
cnt: cnt,
}
}
// symbolsIter implements StringIter.
type symbolsIter struct {
d encoding.Decbuf
cnt int
cur string
err error
}
func (s *symbolsIter) Next() bool {
if s.cnt == 0 || s.err != nil {
return false
}
s.cur = yoloString(s.d.UvarintBytes())
s.cnt--
if s.d.Err() != nil {
s.err = s.d.Err()
return false
}
return true
}
func (s symbolsIter) At() string { return s.cur }
func (s symbolsIter) Err() error { return s.err }
// ReadPostingsOffsetTable reads the postings offset table and at the given position calls f for each
// found entry.
// The name and value parameters passed to f reuse the backing memory of the underlying byte slice,
// so they shouldn't be persisted without previously copying them.
// If f returns an error it stops decoding and returns the received error.
func ReadPostingsOffsetTable(bs ByteSlice, off uint64, f func(name, value []byte, postingsOffset uint64, labelOffset int) error) error {
d := encoding.NewDecbufAt(bs, int(off), castagnoliTable)
startLen := d.Len()
cnt := d.Be32()
for d.Err() == nil && d.Len() > 0 && cnt > 0 {
offsetPos := startLen - d.Len()
if keyCount := d.Uvarint(); keyCount != 2 {
return fmt.Errorf("unexpected number of keys for postings offset table %d", keyCount)
}
name := d.UvarintBytes()
value := d.UvarintBytes()
o := d.Uvarint64()
if d.Err() != nil {
break
}
if err := f(name, value, o, offsetPos); err != nil {
return err
}
cnt--
}
return d.Err()
}
// Close the reader and its underlying resources.
func (r *Reader) Close() error {
return r.c.Close()
}
func (r *Reader) lookupSymbol(ctx context.Context, o uint32) (string, error) {
if s, ok := r.nameSymbols[o]; ok {
return s, nil
}
return r.symbols.Lookup(o)
}
// Symbols returns an iterator over the symbols that exist within the index.
func (r *Reader) Symbols() StringIter {
return r.symbols.Iter()
}
// SymbolTableSize returns the symbol table size in bytes.
func (r *Reader) SymbolTableSize() uint64 {
return uint64(r.symbols.Size())
}
// SortedLabelValues returns value tuples that exist for the given label name.
// It is not safe to use the return value beyond the lifetime of the byte slice
// passed into the Reader.
func (r *Reader) SortedLabelValues(ctx context.Context, name string, matchers ...*labels.Matcher) ([]string, error) {
values, err := r.LabelValues(ctx, name, matchers...)
if err == nil && r.version == FormatV1 {
slices.Sort(values)
}
return values, err
}
// LabelValues returns value tuples that exist for the given label name.
// It is not safe to use the return value beyond the lifetime of the byte slice
// passed into the Reader.
// TODO(replay): Support filtering by matchers.
func (r *Reader) LabelValues(ctx context.Context, name string, matchers ...*labels.Matcher) ([]string, error) {
if len(matchers) > 0 {
return nil, fmt.Errorf("matchers parameter is not implemented: %+v", matchers)
}
if r.version == FormatV1 {
e, ok := r.postingsV1[name]
if !ok {
return nil, nil
}
values := make([]string, 0, len(e))
for k := range e {
values = append(values, k)
}
return values, nil
}
e, ok := r.postings[name]
if !ok {
return nil, nil
}
if len(e) == 0 {
return nil, nil
}
values := make([]string, 0, len(e)*symbolFactor)
d := encoding.NewDecbufAt(r.b, int(r.toc.PostingsTable), nil)
d.Skip(e[0].off)
lastVal := e[len(e)-1].value
skip := 0
for d.Err() == nil && ctx.Err() == nil {
if skip == 0 {
// These are always the same number of bytes,
// and it's faster to skip than parse.
skip = d.Len()
d.Uvarint() // Keycount.
d.UvarintBytes() // Label name.
skip -= d.Len()
} else {
d.Skip(skip)
}
s := yoloString(d.UvarintBytes()) // Label value.
values = append(values, s)
if s == lastVal {
break
}
d.Uvarint64() // Offset.
}
if d.Err() != nil {
return nil, fmt.Errorf("get postings offset entry: %w", d.Err())
}
return values, ctx.Err()
}
// LabelNamesFor returns all the label names for the series referred to by IDs.
// The names returned are sorted.
func (r *Reader) LabelNamesFor(ctx context.Context, ids ...storage.SeriesRef) ([]string, error) {
// Gather offsetsMap the name offsetsMap in the symbol table first
offsetsMap := make(map[uint32]struct{})
for _, id := range ids {
if ctx.Err() != nil {
return nil, ctx.Err()
}
offset := id
// In version 2 series IDs are no longer exact references but series are 16-byte padded
// and the ID is the multiple of 16 of the actual position.
if r.version == FormatV2 {
offset = id * seriesByteAlign
}
d := encoding.NewDecbufUvarintAt(r.b, int(offset), castagnoliTable)
buf := d.Get()
if d.Err() != nil {
return nil, fmt.Errorf("get buffer for series: %w", d.Err())
}
offsets, err := r.dec.LabelNamesOffsetsFor(buf)
if err != nil {
return nil, fmt.Errorf("get label name offsets: %w", err)
}
for _, off := range offsets {
offsetsMap[off] = struct{}{}
}
}
// Lookup the unique symbols.
names := make([]string, 0, len(offsetsMap))
for off := range offsetsMap {
name, err := r.lookupSymbol(ctx, off)
if err != nil {
return nil, fmt.Errorf("lookup symbol in LabelNamesFor: %w", err)
}
names = append(names, name)
}
slices.Sort(names)
return names, nil
}
// LabelValueFor returns label value for the given label name in the series referred to by ID.
func (r *Reader) LabelValueFor(ctx context.Context, id storage.SeriesRef, label string) (string, error) {
offset := id
// In version 2 series IDs are no longer exact references but series are 16-byte padded
// and the ID is the multiple of 16 of the actual position.
if r.version == FormatV2 {
offset = id * seriesByteAlign
}
d := encoding.NewDecbufUvarintAt(r.b, int(offset), castagnoliTable)
buf := d.Get()
if d.Err() != nil {
return "", fmt.Errorf("label values for: %w", d.Err())
}
value, err := r.dec.LabelValueFor(ctx, buf, label)
if err != nil {
return "", storage.ErrNotFound
}
if value == "" {
return "", storage.ErrNotFound
}
return value, nil
}
// Series reads the series with the given ID and writes its labels and chunks into builder and chks.
func (r *Reader) Series(id storage.SeriesRef, builder *labels.ScratchBuilder, chks *[]chunks.Meta) error {
offset := id
// In version 2 series IDs are no longer exact references but series are 16-byte padded
// and the ID is the multiple of 16 of the actual position.
if r.version == FormatV2 {
offset = id * seriesByteAlign
}
d := encoding.NewDecbufUvarintAt(r.b, int(offset), castagnoliTable)
if d.Err() != nil {
return d.Err()
}
builder.SetSymbolTable(r.st)
builder.Reset()
err := r.dec.Series(d.Get(), builder, chks)
if err != nil {
return fmt.Errorf("read series: %w", err)
}
return nil
}
func (r *Reader) Postings(ctx context.Context, name string, values ...string) (Postings, error) {
if r.version == FormatV1 {
e, ok := r.postingsV1[name]
if !ok {
return EmptyPostings(), nil
}
res := make([]Postings, 0, len(values))
for _, v := range values {
postingsOff, ok := e[v]
if !ok {
continue
}
// Read from the postings table.
d := encoding.NewDecbufAt(r.b, int(postingsOff), castagnoliTable)
_, p, err := r.dec.Postings(d.Get())
if err != nil {
return nil, fmt.Errorf("decode postings: %w", err)
}
res = append(res, p)
}
return Merge(ctx, res...), nil
}
e, ok := r.postings[name]
if !ok {
return EmptyPostings(), nil
}
if len(values) == 0 {
return EmptyPostings(), nil
}
slices.Sort(values) // Values must be in order so we can step through the table on disk.
res := make([]Postings, 0, len(values))
skip := 0
valueIndex := 0
for valueIndex < len(values) && values[valueIndex] < e[0].value {
// Discard values before the start.
valueIndex++
}
for valueIndex < len(values) {
value := values[valueIndex]
i := sort.Search(len(e), func(i int) bool { return e[i].value >= value })
if i == len(e) {
// We're past the end.
break
}
if i > 0 && e[i].value != value {
// Need to look from previous entry.
i--
}
// Don't Crc32 the entire postings offset table, this is very slow
// so hope any issues were caught at startup.
d := encoding.NewDecbufAt(r.b, int(r.toc.PostingsTable), nil)
d.Skip(e[i].off)
// Iterate on the offset table.
var postingsOff uint64 // The offset into the postings table.
for d.Err() == nil && ctx.Err() == nil {
if skip == 0 {
// These are always the same number of bytes,
// and it's faster to skip than parse.
skip = d.Len()
d.Uvarint() // Keycount.
d.UvarintBytes() // Label name.
skip -= d.Len()
} else {
d.Skip(skip)
}
v := d.UvarintBytes() // Label value.
postingsOff = d.Uvarint64() // Offset.
for string(v) >= value {
if string(v) == value {
// Read from the postings table.
d2 := encoding.NewDecbufAt(r.b, int(postingsOff), castagnoliTable)
_, p, err := r.dec.Postings(d2.Get())
if err != nil {
return nil, fmt.Errorf("decode postings: %w", err)
}
res = append(res, p)
}
valueIndex++
if valueIndex == len(values) {
break
}
value = values[valueIndex]
}
if i+1 == len(e) || value >= e[i+1].value || valueIndex == len(values) {
// Need to go to a later postings offset entry, if there is one.
break
}
}
if d.Err() != nil {
return nil, fmt.Errorf("get postings offset entry: %w", d.Err())
}
if ctx.Err() != nil {
return nil, fmt.Errorf("get postings offset entry: %w", ctx.Err())
}
}
return Merge(ctx, res...), nil
}
// SortedPostings returns the given postings list reordered so that the backing series
// are sorted.
func (r *Reader) SortedPostings(p Postings) Postings {
return p
}
// ShardedPostings returns a postings list filtered by the provided shardIndex out of shardCount.
func (r *Reader) ShardedPostings(p Postings, shardIndex, shardCount uint64) Postings {
var (
out = make([]storage.SeriesRef, 0, 128)
bufLbls = labels.ScratchBuilder{}
)
for p.Next() {
id := p.At()
// Get the series labels (no chunks).
err := r.Series(id, &bufLbls, nil)
if err != nil {
return ErrPostings(fmt.Errorf("series %d not found", id))
}
// Check if the series belong to the shard.
if labels.StableHash(bufLbls.Labels())%shardCount != shardIndex {
continue
}
out = append(out, id)
}
return NewListPostings(out)
}
// Size returns the size of an index file.
func (r *Reader) Size() int64 {
return int64(r.b.Len())
}
// LabelNames returns all the unique label names present in the index.
// TODO(twilkie) implement support for matchers.
func (r *Reader) LabelNames(_ context.Context, matchers ...*labels.Matcher) ([]string, error) {
if len(matchers) > 0 {
return nil, fmt.Errorf("matchers parameter is not implemented: %+v", matchers)
}
labelNames := make([]string, 0, len(r.postings))
for name := range r.postings {
if name == allPostingsKey.Name {
// This is not from any metric.
continue
}
labelNames = append(labelNames, name)
}
slices.Sort(labelNames)
return labelNames, nil
}
// NewStringListIter returns a StringIter for the given sorted list of strings.
func NewStringListIter(s []string) StringIter {
return &stringListIter{l: s}
}
// stringListIter implements StringIter.
type stringListIter struct {
l []string
cur string
}
func (s *stringListIter) Next() bool {
if len(s.l) == 0 {
return false
}
s.cur = s.l[0]
s.l = s.l[1:]
return true
}
func (s stringListIter) At() string { return s.cur }
func (s stringListIter) Err() error { return nil }
// Decoder provides decoding methods for the v1 and v2 index file format.
//
// It currently does not contain decoding methods for all entry types but can be extended
// by them if there's demand.
type Decoder struct {
LookupSymbol func(context.Context, uint32) (string, error)
}
// Postings returns a postings list for b and its number of elements.
func (dec *Decoder) Postings(b []byte) (int, Postings, error) {
d := encoding.Decbuf{B: b}
n := d.Be32int()
l := d.Get()
if d.Err() != nil {
return 0, nil, d.Err()
}
if len(l) != 4*n {
return 0, nil, fmt.Errorf("unexpected postings length, should be %d bytes for %d postings, got %d bytes", 4*n, n, len(l))
}
return n, newBigEndianPostings(l), nil
}
// LabelNamesOffsetsFor decodes the offsets of the name symbols for a given series.
// They are returned in the same order they're stored, which should be sorted lexicographically.
func (dec *Decoder) LabelNamesOffsetsFor(b []byte) ([]uint32, error) {
d := encoding.Decbuf{B: b}
k := d.Uvarint()
offsets := make([]uint32, k)
for i := 0; i < k; i++ {
offsets[i] = uint32(d.Uvarint())
_ = d.Uvarint() // skip the label value
if d.Err() != nil {
return nil, fmt.Errorf("read series label offsets: %w", d.Err())
}
}
return offsets, d.Err()
}
// LabelValueFor decodes a label for a given series.
func (dec *Decoder) LabelValueFor(ctx context.Context, b []byte, label string) (string, error) {
d := encoding.Decbuf{B: b}
k := d.Uvarint()
for i := 0; i < k; i++ {
lno := uint32(d.Uvarint())
lvo := uint32(d.Uvarint())
if d.Err() != nil {
return "", fmt.Errorf("read series label offsets: %w", d.Err())
}
ln, err := dec.LookupSymbol(ctx, lno)
if err != nil {
return "", fmt.Errorf("lookup label name: %w", err)
}
if ln == label {
lv, err := dec.LookupSymbol(ctx, lvo)
if err != nil {
return "", fmt.Errorf("lookup label value: %w", err)
}
return lv, nil
}
}
return "", d.Err()
}
// Series decodes a series entry from the given byte slice into builder and chks.
// Previous contents of builder can be overwritten - make sure you copy before retaining.
// Skips reading chunks metadata if chks is nil.
func (dec *Decoder) Series(b []byte, builder *labels.ScratchBuilder, chks *[]chunks.Meta) error {
builder.Reset()
if chks != nil {
*chks = (*chks)[:0]
}
d := encoding.Decbuf{B: b}
k := d.Uvarint()
for i := 0; i < k; i++ {
lno := uint32(d.Uvarint())
lvo := uint32(d.Uvarint())
if d.Err() != nil {
return fmt.Errorf("read series label offsets: %w", d.Err())
}
ln, err := dec.LookupSymbol(context.TODO(), lno)
if err != nil {
return fmt.Errorf("lookup label name: %w", err)
}
lv, err := dec.LookupSymbol(context.TODO(), lvo)
if err != nil {
return fmt.Errorf("lookup label value: %w", err)
}
builder.Add(ln, lv)
}
// Skip reading chunks metadata if chks is nil.
if chks == nil {
return d.Err()
}
// Read the chunks meta data.
k = d.Uvarint()
if k == 0 {
return d.Err()
}
t0 := d.Varint64()
maxt := int64(d.Uvarint64()) + t0
ref0 := int64(d.Uvarint64())
*chks = append(*chks, chunks.Meta{
Ref: chunks.ChunkRef(ref0),
MinTime: t0,
MaxTime: maxt,
})
t0 = maxt
for i := 1; i < k; i++ {
mint := int64(d.Uvarint64()) + t0
maxt := int64(d.Uvarint64()) + mint
ref0 += d.Varint64()
t0 = maxt
if d.Err() != nil {
return fmt.Errorf("read meta for chunk %d: %w", i, d.Err())
}
*chks = append(*chks, chunks.Meta{
Ref: chunks.ChunkRef(ref0),
MinTime: mint,
MaxTime: maxt,
})
}
return d.Err()
}
func yoloString(b []byte) string {
return *((*string)(unsafe.Pointer(&b)))
}
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