prometheus/tsdb/ooo_head_read.go
Jeanette Tan 71a36d2396 Very minor refactor of the integer overflow fix
Signed-off-by: Jeanette Tan <jeanette.tan@grafana.com>
2023-10-19 13:17:46 +08:00

466 lines
14 KiB
Go

// Copyright 2022 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.
// nolint:revive // Many unused function arguments in this file by design.
package tsdb
import (
"context"
"errors"
"math"
"golang.org/x/exp/slices"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/storage"
"github.com/prometheus/prometheus/tsdb/chunkenc"
"github.com/prometheus/prometheus/tsdb/chunks"
"github.com/prometheus/prometheus/tsdb/index"
"github.com/prometheus/prometheus/tsdb/tombstones"
)
var _ IndexReader = &OOOHeadIndexReader{}
// OOOHeadIndexReader implements IndexReader so ooo samples in the head can be
// accessed.
// It also has a reference to headIndexReader so we can leverage on its
// IndexReader implementation for all the methods that remain the same. We
// decided to do this to avoid code duplication.
// The only methods that change are the ones about getting Series and Postings.
type OOOHeadIndexReader struct {
*headIndexReader // A reference to the headIndexReader so we can reuse as many interface implementation as possible.
}
func NewOOOHeadIndexReader(head *Head, mint, maxt int64) *OOOHeadIndexReader {
hr := &headIndexReader{
head: head,
mint: mint,
maxt: maxt,
}
return &OOOHeadIndexReader{hr}
}
func (oh *OOOHeadIndexReader) Series(ref storage.SeriesRef, builder *labels.ScratchBuilder, chks *[]chunks.Meta) error {
return oh.series(ref, builder, chks, 0)
}
// The passed lastMmapRef tells upto what max m-map chunk that we can consider.
// If it is 0, it means all chunks need to be considered.
// If it is non-0, then the oooHeadChunk must not be considered.
func (oh *OOOHeadIndexReader) series(ref storage.SeriesRef, builder *labels.ScratchBuilder, chks *[]chunks.Meta, lastMmapRef chunks.ChunkDiskMapperRef) error {
s := oh.head.series.getByID(chunks.HeadSeriesRef(ref))
if s == nil {
oh.head.metrics.seriesNotFound.Inc()
return storage.ErrNotFound
}
builder.Assign(s.lset)
if chks == nil {
return nil
}
s.Lock()
defer s.Unlock()
*chks = (*chks)[:0]
if s.ooo == nil {
return nil
}
tmpChks := make([]chunks.Meta, 0, len(s.ooo.oooMmappedChunks))
// We define these markers to track the last chunk reference while we
// fill the chunk meta.
// These markers are useful to give consistent responses to repeated queries
// even if new chunks that might be overlapping or not are added afterwards.
// Also, lastMinT and lastMaxT are initialized to the max int as a sentinel
// value to know they are unset.
var lastChunkRef chunks.ChunkRef
lastMinT, lastMaxT := int64(math.MaxInt64), int64(math.MaxInt64)
addChunk := func(minT, maxT int64, ref chunks.ChunkRef) {
// the first time we get called is for the last included chunk.
// set the markers accordingly
if lastMinT == int64(math.MaxInt64) {
lastChunkRef = ref
lastMinT = minT
lastMaxT = maxT
}
tmpChks = append(tmpChks, chunks.Meta{
MinTime: minT,
MaxTime: maxT,
Ref: ref,
OOOLastRef: lastChunkRef,
OOOLastMinTime: lastMinT,
OOOLastMaxTime: lastMaxT,
})
}
// Collect all chunks that overlap the query range, in order from most recent to most old,
// so we can set the correct markers.
if s.ooo.oooHeadChunk != nil {
c := s.ooo.oooHeadChunk
if c.OverlapsClosedInterval(oh.mint, oh.maxt) && lastMmapRef == 0 {
ref := chunks.ChunkRef(chunks.NewHeadChunkRef(s.ref, s.oooHeadChunkID(len(s.ooo.oooMmappedChunks))))
addChunk(c.minTime, c.maxTime, ref)
}
}
for i := len(s.ooo.oooMmappedChunks) - 1; i >= 0; i-- {
c := s.ooo.oooMmappedChunks[i]
if c.OverlapsClosedInterval(oh.mint, oh.maxt) && (lastMmapRef == 0 || lastMmapRef.GreaterThanOrEqualTo(c.ref)) {
ref := chunks.ChunkRef(chunks.NewHeadChunkRef(s.ref, s.oooHeadChunkID(i)))
addChunk(c.minTime, c.maxTime, ref)
}
}
// There is nothing to do if we did not collect any chunk.
if len(tmpChks) == 0 {
return nil
}
// Next we want to sort all the collected chunks by min time so we can find
// those that overlap.
slices.SortFunc(tmpChks, lessByMinTimeAndMinRef)
// Next we want to iterate the sorted collected chunks and only return the
// chunks Meta the first chunk that overlaps with others.
// Example chunks of a series: 5:(100, 200) 6:(500, 600) 7:(150, 250) 8:(550, 650)
// In the example 5 overlaps with 7 and 6 overlaps with 8 so we only want to
// return chunk Metas for chunk 5 and chunk 6e
*chks = append(*chks, tmpChks[0])
maxTime := tmpChks[0].MaxTime // Tracks the maxTime of the previous "to be merged chunk".
for _, c := range tmpChks[1:] {
switch {
case c.MinTime > maxTime:
*chks = append(*chks, c)
maxTime = c.MaxTime
case c.MaxTime > maxTime:
maxTime = c.MaxTime
(*chks)[len(*chks)-1].MaxTime = c.MaxTime
}
}
return nil
}
// LabelValues needs to be overridden from the headIndexReader implementation due
// to the check that happens at the beginning where we make sure that the query
// interval overlaps with the head minooot and maxooot.
func (oh *OOOHeadIndexReader) LabelValues(ctx context.Context, name string, matchers ...*labels.Matcher) ([]string, error) {
if oh.maxt < oh.head.MinOOOTime() || oh.mint > oh.head.MaxOOOTime() {
return []string{}, nil
}
if len(matchers) == 0 {
return oh.head.postings.LabelValues(ctx, name), nil
}
return labelValuesWithMatchers(ctx, oh, name, matchers...)
}
type chunkMetaAndChunkDiskMapperRef struct {
meta chunks.Meta
ref chunks.ChunkDiskMapperRef
origMinT int64
origMaxT int64
}
func refLessByMinTimeAndMinRef(a, b chunkMetaAndChunkDiskMapperRef) int {
switch {
case a.meta.MinTime < b.meta.MinTime:
return -1
case a.meta.MinTime > b.meta.MinTime:
return 1
}
switch {
case a.meta.Ref < b.meta.Ref:
return -1
case a.meta.Ref > b.meta.Ref:
return 1
default:
return 0
}
}
func lessByMinTimeAndMinRef(a, b chunks.Meta) int {
switch {
case a.MinTime < b.MinTime:
return -1
case a.MinTime > b.MinTime:
return 1
}
switch {
case a.Ref < b.Ref:
return -1
case a.Ref > b.Ref:
return 1
default:
return 0
}
}
func (oh *OOOHeadIndexReader) Postings(ctx context.Context, name string, values ...string) (index.Postings, error) {
switch len(values) {
case 0:
return index.EmptyPostings(), nil
case 1:
return oh.head.postings.Get(name, values[0]), nil // TODO(ganesh) Also call GetOOOPostings
default:
// TODO(ganesh) We want to only return postings for out of order series.
res := make([]index.Postings, 0, len(values))
for _, value := range values {
res = append(res, oh.head.postings.Get(name, value)) // TODO(ganesh) Also call GetOOOPostings
}
return index.Merge(ctx, res...), nil
}
}
type OOOHeadChunkReader struct {
head *Head
mint, maxt int64
}
func NewOOOHeadChunkReader(head *Head, mint, maxt int64) *OOOHeadChunkReader {
return &OOOHeadChunkReader{
head: head,
mint: mint,
maxt: maxt,
}
}
func (cr OOOHeadChunkReader) Chunk(meta chunks.Meta) (chunkenc.Chunk, error) {
sid, _ := chunks.HeadChunkRef(meta.Ref).Unpack()
s := cr.head.series.getByID(sid)
// This means that the series has been garbage collected.
if s == nil {
return nil, storage.ErrNotFound
}
s.Lock()
if s.ooo == nil {
// There is no OOO data for this series.
s.Unlock()
return nil, storage.ErrNotFound
}
c, err := s.oooMergedChunk(meta, cr.head.chunkDiskMapper, cr.mint, cr.maxt)
s.Unlock()
if err != nil {
return nil, err
}
// This means that the query range did not overlap with the requested chunk.
if len(c.chunks) == 0 {
return nil, storage.ErrNotFound
}
return c, nil
}
func (cr OOOHeadChunkReader) Close() error {
return nil
}
type OOOCompactionHead struct {
oooIR *OOOHeadIndexReader
lastMmapRef chunks.ChunkDiskMapperRef
lastWBLFile int
postings []storage.SeriesRef
chunkRange int64
mint, maxt int64 // Among all the compactable chunks.
}
// NewOOOCompactionHead does the following:
// 1. M-maps all the in-memory ooo chunks.
// 2. Compute the expected block ranges while iterating through all ooo series and store it.
// 3. Store the list of postings having ooo series.
// 4. Cuts a new WBL file for the OOO WBL.
// All the above together have a bit of CPU and memory overhead, and can have a bit of impact
// on the sample append latency. So call NewOOOCompactionHead only right before compaction.
func NewOOOCompactionHead(ctx context.Context, head *Head) (*OOOCompactionHead, error) {
ch := &OOOCompactionHead{
chunkRange: head.chunkRange.Load(),
mint: math.MaxInt64,
maxt: math.MinInt64,
}
if head.wbl != nil {
lastWBLFile, err := head.wbl.NextSegmentSync()
if err != nil {
return nil, err
}
ch.lastWBLFile = lastWBLFile
}
ch.oooIR = NewOOOHeadIndexReader(head, math.MinInt64, math.MaxInt64)
n, v := index.AllPostingsKey()
// TODO: verify this gets only ooo samples.
p, err := ch.oooIR.Postings(ctx, n, v)
if err != nil {
return nil, err
}
p = ch.oooIR.SortedPostings(p)
var lastSeq, lastOff int
for p.Next() {
seriesRef := p.At()
ms := head.series.getByID(chunks.HeadSeriesRef(seriesRef))
if ms == nil {
continue
}
// M-map the in-memory chunk and keep track of the last one.
// Also build the block ranges -> series map.
// TODO: consider having a lock specifically for ooo data.
ms.Lock()
if ms.ooo == nil {
ms.Unlock()
continue
}
mmapRef := ms.mmapCurrentOOOHeadChunk(head.chunkDiskMapper)
if mmapRef == 0 && len(ms.ooo.oooMmappedChunks) > 0 {
// Nothing was m-mapped. So take the mmapRef from the existing slice if it exists.
mmapRef = ms.ooo.oooMmappedChunks[len(ms.ooo.oooMmappedChunks)-1].ref
}
seq, off := mmapRef.Unpack()
if seq > lastSeq || (seq == lastSeq && off > lastOff) {
ch.lastMmapRef, lastSeq, lastOff = mmapRef, seq, off
}
if len(ms.ooo.oooMmappedChunks) > 0 {
ch.postings = append(ch.postings, seriesRef)
for _, c := range ms.ooo.oooMmappedChunks {
if c.minTime < ch.mint {
ch.mint = c.minTime
}
if c.maxTime > ch.maxt {
ch.maxt = c.maxTime
}
}
}
ms.Unlock()
}
return ch, nil
}
func (ch *OOOCompactionHead) Index() (IndexReader, error) {
return NewOOOCompactionHeadIndexReader(ch), nil
}
func (ch *OOOCompactionHead) Chunks() (ChunkReader, error) {
return NewOOOHeadChunkReader(ch.oooIR.head, ch.oooIR.mint, ch.oooIR.maxt), nil
}
func (ch *OOOCompactionHead) Tombstones() (tombstones.Reader, error) {
return tombstones.NewMemTombstones(), nil
}
func (ch *OOOCompactionHead) Meta() BlockMeta {
var id [16]byte
copy(id[:], "copy(id[:], \"ooo_compact_head\")")
return BlockMeta{
MinTime: ch.mint,
MaxTime: ch.maxt,
ULID: id,
Stats: BlockStats{
NumSeries: uint64(len(ch.postings)),
},
}
}
// CloneForTimeRange clones the OOOCompactionHead such that the IndexReader and ChunkReader
// obtained from this only looks at the m-map chunks within the given time ranges while not looking
// beyond the ch.lastMmapRef.
// Only the method of BlockReader interface are valid for the cloned OOOCompactionHead.
func (ch *OOOCompactionHead) CloneForTimeRange(mint, maxt int64) *OOOCompactionHead {
return &OOOCompactionHead{
oooIR: NewOOOHeadIndexReader(ch.oooIR.head, mint, maxt),
lastMmapRef: ch.lastMmapRef,
postings: ch.postings,
chunkRange: ch.chunkRange,
mint: ch.mint,
maxt: ch.maxt,
}
}
func (ch *OOOCompactionHead) Size() int64 { return 0 }
func (ch *OOOCompactionHead) MinTime() int64 { return ch.mint }
func (ch *OOOCompactionHead) MaxTime() int64 { return ch.maxt }
func (ch *OOOCompactionHead) ChunkRange() int64 { return ch.chunkRange }
func (ch *OOOCompactionHead) LastMmapRef() chunks.ChunkDiskMapperRef { return ch.lastMmapRef }
func (ch *OOOCompactionHead) LastWBLFile() int { return ch.lastWBLFile }
type OOOCompactionHeadIndexReader struct {
ch *OOOCompactionHead
}
func NewOOOCompactionHeadIndexReader(ch *OOOCompactionHead) IndexReader {
return &OOOCompactionHeadIndexReader{ch: ch}
}
func (ir *OOOCompactionHeadIndexReader) Symbols() index.StringIter {
return ir.ch.oooIR.Symbols()
}
func (ir *OOOCompactionHeadIndexReader) Postings(_ context.Context, name string, values ...string) (index.Postings, error) {
n, v := index.AllPostingsKey()
if name != n || len(values) != 1 || values[0] != v {
return nil, errors.New("only AllPostingsKey is supported")
}
return index.NewListPostings(ir.ch.postings), nil
}
func (ir *OOOCompactionHeadIndexReader) SortedPostings(p index.Postings) index.Postings {
// This will already be sorted from the Postings() call above.
return p
}
func (ir *OOOCompactionHeadIndexReader) Series(ref storage.SeriesRef, builder *labels.ScratchBuilder, chks *[]chunks.Meta) error {
return ir.ch.oooIR.series(ref, builder, chks, ir.ch.lastMmapRef)
}
func (ir *OOOCompactionHeadIndexReader) SortedLabelValues(_ context.Context, name string, matchers ...*labels.Matcher) ([]string, error) {
return nil, errors.New("not implemented")
}
func (ir *OOOCompactionHeadIndexReader) LabelValues(_ context.Context, name string, matchers ...*labels.Matcher) ([]string, error) {
return nil, errors.New("not implemented")
}
func (ir *OOOCompactionHeadIndexReader) PostingsForMatchers(_ context.Context, concurrent bool, ms ...*labels.Matcher) (index.Postings, error) {
return nil, errors.New("not implemented")
}
func (ir *OOOCompactionHeadIndexReader) LabelNames(context.Context, ...*labels.Matcher) ([]string, error) {
return nil, errors.New("not implemented")
}
func (ir *OOOCompactionHeadIndexReader) LabelValueFor(context.Context, storage.SeriesRef, string) (string, error) {
return "", errors.New("not implemented")
}
func (ir *OOOCompactionHeadIndexReader) LabelNamesFor(ctx context.Context, ids ...storage.SeriesRef) ([]string, error) {
return nil, errors.New("not implemented")
}
func (ir *OOOCompactionHeadIndexReader) Close() error {
return ir.ch.oooIR.Close()
}