tidb engine 源码
tidb engine 代码
文件路径：/br/pkg/lightning/backend/local/engine.go
// Copyright 2021 PingCAP, Inc.
//
// 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 local
import (
"bytes"
"container/heap"
"context"
"encoding/binary"
"encoding/json"
"fmt"
"io"
"os"
"path/filepath"
"sync"
"time"
"github.com/cockroachdb/pebble"
"github.com/cockroachdb/pebble/sstable"
"github.com/google/btree"
"github.com/google/uuid"
"github.com/pingcap/errors"
"github.com/pingcap/tidb/br/pkg/lightning/backend"
"github.com/pingcap/tidb/br/pkg/lightning/backend/kv"
"github.com/pingcap/tidb/br/pkg/lightning/checkpoints"
"github.com/pingcap/tidb/br/pkg/lightning/common"
"github.com/pingcap/tidb/br/pkg/lightning/errormanager"
"github.com/pingcap/tidb/br/pkg/lightning/log"
"github.com/pingcap/tidb/br/pkg/logutil"
"github.com/pingcap/tidb/br/pkg/membuf"
"github.com/pingcap/tidb/parser/model"
"github.com/pingcap/tidb/util/hack"
"go.uber.org/atomic"
"go.uber.org/zap"
"golang.org/x/exp/slices"
"golang.org/x/sync/errgroup"
)
var (
engineMetaKey = []byte{0, 'm', 'e', 't', 'a'}
normalIterStartKey = []byte{1}
)
type importMutexState uint32
const (
importMutexStateImport importMutexState = 1 << iota
importMutexStateClose
// importMutexStateReadLock is a special state because in this state we lock engine with read lock
// and add isImportingAtomic with this value. In other state, we directly store with the state value.
// so this must always the last value of this enum.
importMutexStateReadLock
)
// engineMeta contains some field that is necessary to continue the engine restore/import process.
// These field should be written to disk when we update chunk checkpoint
type engineMeta struct {
TS uint64 `json:"ts"`
// Length is the number of KV pairs stored by the engine.
Length atomic.Int64 `json:"length"`
// TotalSize is the total pre-compressed KV byte size stored by engine.
TotalSize atomic.Int64 `json:"total_size"`
}
type syncedRanges struct {
sync.Mutex
ranges []Range
}
func (r *syncedRanges) add(g Range) {
r.Lock()
r.ranges = append(r.ranges, g)
r.Unlock()
}
func (r *syncedRanges) reset() {
r.Lock()
r.ranges = r.ranges[:0]
r.Unlock()
}
type Engine struct {
engineMeta
closed atomic.Bool
db *pebble.DB
UUID uuid.UUID
localWriters sync.Map
// isImportingAtomic is an atomic variable indicating whether this engine is importing.
// This should not be used as a "spin lock" indicator.
isImportingAtomic atomic.Uint32
// flush and ingest sst hold the rlock, other operation hold the wlock.
mutex sync.RWMutex
ctx context.Context
cancel context.CancelFunc
sstDir string
sstMetasChan chan metaOrFlush
ingestErr common.OnceError
wg sync.WaitGroup
sstIngester sstIngester
finishedRanges syncedRanges
// sst seq lock
seqLock sync.Mutex
// seq number for incoming sst meta
nextSeq int32
// max seq of sst metas ingested into pebble
finishedMetaSeq atomic.Int32
config backend.LocalEngineConfig
tableInfo *checkpoints.TidbTableInfo
// total size of SST files waiting to be ingested
pendingFileSize atomic.Int64
// statistics for pebble kv iter.
importedKVSize atomic.Int64
importedKVCount atomic.Int64
keyAdapter KeyAdapter
duplicateDetection bool
duplicateDB *pebble.DB
errorMgr *errormanager.ErrorManager
logger log.Logger
}
func (e *Engine) setError(err error) {
if err != nil {
e.ingestErr.Set(err)
e.cancel()
}
}
func (e *Engine) Close() error {
e.logger.Debug("closing local engine", zap.Stringer("engine", e.UUID), zap.Stack("stack"))
if e.db == nil {
return nil
}
err := errors.Trace(e.db.Close())
e.db = nil
return err
}
// Cleanup remove meta and db files
func (e *Engine) Cleanup(dataDir string) error {
if err := os.RemoveAll(e.sstDir); err != nil {
return errors.Trace(err)
}
dbPath := filepath.Join(dataDir, e.UUID.String())
return os.RemoveAll(dbPath)
}
// Exist checks if db folder existing (meta sometimes won't flush before lightning exit)
func (e *Engine) Exist(dataDir string) error {
dbPath := filepath.Join(dataDir, e.UUID.String())
if _, err := os.Stat(dbPath); err != nil {
return err
}
return nil
}
func isStateLocked(state importMutexState) bool {
return state&(importMutexStateClose|importMutexStateImport) != 0
}
func (e *Engine) isLocked() bool {
// the engine is locked only in import or close state.
return isStateLocked(importMutexState(e.isImportingAtomic.Load()))
}
// rLock locks the local file with shard read state. Only used for flush and ingest SST files.
func (e *Engine) rLock() {
e.mutex.RLock()
e.isImportingAtomic.Add(uint32(importMutexStateReadLock))
}
func (e *Engine) rUnlock() {
if e == nil {
return
}
e.isImportingAtomic.Sub(uint32(importMutexStateReadLock))
e.mutex.RUnlock()
}
// lock locks the local file for importing.
func (e *Engine) lock(state importMutexState) {
e.mutex.Lock()
e.isImportingAtomic.Store(uint32(state))
}
// lockUnless tries to lock the local file unless it is already locked into the state given by
// ignoreStateMask. Returns whether the lock is successful.
func (e *Engine) lockUnless(newState, ignoreStateMask importMutexState) bool {
curState := e.isImportingAtomic.Load()
if curState&uint32(ignoreStateMask) != 0 {
return false
}
e.lock(newState)
return true
}
// tryRLock tries to read-lock the local file unless it is already write locked.
// Returns whether the lock is successful.
func (e *Engine) tryRLock() bool {
curState := e.isImportingAtomic.Load()
// engine is in import/close state.
if isStateLocked(importMutexState(curState)) {
return false
}
e.rLock()
return true
}
func (e *Engine) unlock() {
if e == nil {
return
}
e.isImportingAtomic.Store(0)
e.mutex.Unlock()
}
func (e *Engine) TotalMemorySize() int64 {
var memSize int64 = 0
e.localWriters.Range(func(k, v interface{}) bool {
w := k.(*Writer)
if w.kvBuffer != nil {
w.Lock()
memSize += w.kvBuffer.TotalSize()
w.Unlock()
}
return true
})
return memSize
}
type rangeOffsets struct {
Size uint64
Keys uint64
}
type rangeProperty struct {
Key []byte
rangeOffsets
}
func (r *rangeProperty) Less(than btree.Item) bool {
ta := than.(*rangeProperty)
return bytes.Compare(r.Key, ta.Key) < 0
}
var _ btree.Item = &rangeProperty{}
type rangeProperties []rangeProperty
func (r rangeProperties) Encode() []byte {
b := make([]byte, 0, 1024)
idx := 0
for _, p := range r {
b = append(b, 0, 0, 0, 0)
binary.BigEndian.PutUint32(b[idx:], uint32(len(p.Key)))
idx += 4
b = append(b, p.Key...)
idx += len(p.Key)
b = append(b, 0, 0, 0, 0, 0, 0, 0, 0)
binary.BigEndian.PutUint64(b[idx:], p.Size)
idx += 8
b = append(b, 0, 0, 0, 0, 0, 0, 0, 0)
binary.BigEndian.PutUint64(b[idx:], p.Keys)
idx += 8
}
return b
}
type RangePropertiesCollector struct {
props rangeProperties
lastOffsets rangeOffsets
lastKey []byte
currentOffsets rangeOffsets
propSizeIdxDistance uint64
propKeysIdxDistance uint64
}
func newRangePropertiesCollector() pebble.TablePropertyCollector {
return &RangePropertiesCollector{
props: make([]rangeProperty, 0, 1024),
propSizeIdxDistance: defaultPropSizeIndexDistance,
propKeysIdxDistance: defaultPropKeysIndexDistance,
}
}
func (c *RangePropertiesCollector) sizeInLastRange() uint64 {
return c.currentOffsets.Size - c.lastOffsets.Size
}
func (c *RangePropertiesCollector) keysInLastRange() uint64 {
return c.currentOffsets.Keys - c.lastOffsets.Keys
}
func (c *RangePropertiesCollector) insertNewPoint(key []byte) {
c.lastOffsets = c.currentOffsets
c.props = append(c.props, rangeProperty{Key: append([]byte{}, key...), rangeOffsets: c.currentOffsets})
}
// Add implements `pebble.TablePropertyCollector`.
// Add implements `TablePropertyCollector.Add`.
func (c *RangePropertiesCollector) Add(key pebble.InternalKey, value []byte) error {
if key.Kind() != pebble.InternalKeyKindSet || bytes.Equal(key.UserKey, engineMetaKey) {
return nil
}
c.currentOffsets.Size += uint64(len(value)) + uint64(len(key.UserKey))
c.currentOffsets.Keys++
if len(c.lastKey) == 0 || c.sizeInLastRange() >= c.propSizeIdxDistance ||
c.keysInLastRange() >= c.propKeysIdxDistance {
c.insertNewPoint(key.UserKey)
}
c.lastKey = append(c.lastKey[:0], key.UserKey...)
return nil
}
func (c *RangePropertiesCollector) Finish(userProps map[string]string) error {
if c.sizeInLastRange() > 0 || c.keysInLastRange() > 0 {
c.insertNewPoint(c.lastKey)
}
userProps[propRangeIndex] = string(c.props.Encode())
return nil
}
func (c *RangePropertiesCollector) Name() string {
return propRangeIndex
}
type sizeProperties struct {
totalSize uint64
indexHandles *btree.BTree
}
func newSizeProperties() *sizeProperties {
return &sizeProperties{indexHandles: btree.New(32)}
}
func (s *sizeProperties) add(item *rangeProperty) {
if old := s.indexHandles.ReplaceOrInsert(item); old != nil {
o := old.(*rangeProperty)
item.Keys += o.Keys
item.Size += o.Size
}
}
func (s *sizeProperties) addAll(props rangeProperties) {
prevRange := rangeOffsets{}
for _, r := range props {
s.add(&rangeProperty{
Key: r.Key,
rangeOffsets: rangeOffsets{Keys: r.Keys - prevRange.Keys, Size: r.Size - prevRange.Size},
})
prevRange = r.rangeOffsets
}
if len(props) > 0 {
s.totalSize += props[len(props)-1].Size
}
}
// iter the tree until f return false
func (s *sizeProperties) iter(f func(p *rangeProperty) bool) {
s.indexHandles.Ascend(func(i btree.Item) bool {
prop := i.(*rangeProperty)
return f(prop)
})
}
func decodeRangeProperties(data []byte, keyAdapter KeyAdapter) (rangeProperties, error) {
r := make(rangeProperties, 0, 16)
for len(data) > 0 {
if len(data) < 4 {
return nil, io.ErrUnexpectedEOF
}
keyLen := int(binary.BigEndian.Uint32(data[:4]))
data = data[4:]
if len(data) < keyLen+8*2 {
return nil, io.ErrUnexpectedEOF
}
key := data[:keyLen]
data = data[keyLen:]
size := binary.BigEndian.Uint64(data[:8])
keys := binary.BigEndian.Uint64(data[8:])
data = data[16:]
if !bytes.Equal(key, engineMetaKey) {
userKey, err := keyAdapter.Decode(nil, key)
if err != nil {
return nil, errors.Annotate(err, "failed to decode key with keyAdapter")
}
r = append(r, rangeProperty{Key: userKey, rangeOffsets: rangeOffsets{Size: size, Keys: keys}})
}
}
return r, nil
}
func getSizeProperties(logger log.Logger, db *pebble.DB, keyAdapter KeyAdapter) (*sizeProperties, error) {
sstables, err := db.SSTables(pebble.WithProperties())
if err != nil {
logger.Warn("get sst table properties failed", log.ShortError(err))
return nil, errors.Trace(err)
}
sizeProps := newSizeProperties()
for _, level := range sstables {
for _, info := range level {
if prop, ok := info.Properties.UserProperties[propRangeIndex]; ok {
data := hack.Slice(prop)
rangeProps, err := decodeRangeProperties(data, keyAdapter)
if err != nil {
logger.Warn("decodeRangeProperties failed",
zap.Stringer("fileNum", info.FileNum), log.ShortError(err))
return nil, errors.Trace(err)
}
sizeProps.addAll(rangeProps)
}
}
}
return sizeProps, nil
}
func (e *Engine) getEngineFileSize() backend.EngineFileSize {
e.mutex.RLock()
db := e.db
e.mutex.RUnlock()
var total pebble.LevelMetrics
if db != nil {
metrics := db.Metrics()
total = metrics.Total()
}
var memSize int64
e.localWriters.Range(func(k, v interface{}) bool {
w := k.(*Writer)
if w.writer != nil {
memSize += int64(w.writer.writer.EstimatedSize())
} else {
// if kvs are still in memory, only calculate half of the total size
// in our tests, SST file size is about 50% of the raw kv size
memSize += w.batchSize / 2
}
return true
})
pendingSize := e.pendingFileSize.Load()
// TODO: should also add the in-processing compaction sst writer size into MemSize
return backend.EngineFileSize{
UUID: e.UUID,
DiskSize: total.Size + pendingSize,
MemSize: memSize,
IsImporting: e.isLocked(),
}
}
// either a sstMeta or a flush message
type metaOrFlush struct {
meta *sstMeta
flushCh chan struct{}
}
type metaSeq struct {
// the sequence for this flush message, a flush call can return only if
// all the other flush will lower `flushSeq` are done
flushSeq int32
// the max sstMeta sequence number in this flush, after the flush is done (all SSTs are ingested),
// we can save chunks will a lower meta sequence number safely.
metaSeq int32
}
type metaSeqHeap struct {
arr []metaSeq
}
func (h *metaSeqHeap) Len() int {
return len(h.arr)
}
func (h *metaSeqHeap) Less(i, j int) bool {
return h.arr[i].flushSeq < h.arr[j].flushSeq
}
func (h *metaSeqHeap) Swap(i, j int) {
h.arr[i], h.arr[j] = h.arr[j], h.arr[i]
}
func (h *metaSeqHeap) Push(x interface{}) {
h.arr = append(h.arr, x.(metaSeq))
}
func (h *metaSeqHeap) Pop() interface{} {
item := h.arr[len(h.arr)-1]
h.arr = h.arr[:len(h.arr)-1]
return item
}
func (e *Engine) ingestSSTLoop() {
defer e.wg.Done()
type flushSeq struct {
seq int32
ch chan struct{}
}
seq := atomic.NewInt32(0)
finishedSeq := atomic.NewInt32(0)
var seqLock sync.Mutex
// a flush is finished iff all the compaction&ingest tasks with a lower seq number are finished.
flushQueue := make([]flushSeq, 0)
// inSyncSeqs is a heap that stores all the finished compaction tasks whose seq is bigger than `finishedSeq + 1`
// this mean there are still at lease one compaction task with a lower seq unfinished.
inSyncSeqs := &metaSeqHeap{arr: make([]metaSeq, 0)}
type metaAndSeq struct {
metas []*sstMeta
seq int32
}
concurrency := e.config.CompactConcurrency
// when compaction is disabled, ingest is an serial action, so 1 routine is enough
if !e.config.Compact {
concurrency = 1
}
metaChan := make(chan metaAndSeq, concurrency)
for i := 0; i < concurrency; i++ {
e.wg.Add(1)
go func() {
defer func() {
if e.ingestErr.Get() != nil {
seqLock.Lock()
for _, f := range flushQueue {
f.ch <- struct{}{}
}
flushQueue = flushQueue[:0]
seqLock.Unlock()
}
e.wg.Done()
}()
for {
select {
case <-e.ctx.Done():
return
case metas, ok := <-metaChan:
if !ok {
return
}
ingestMetas := metas.metas
if e.config.Compact {
newMeta, err := e.sstIngester.mergeSSTs(metas.metas, e.sstDir)
if err != nil {
e.setError(err)
return
}
ingestMetas = []*sstMeta{newMeta}
}
// batchIngestSSTs will change ingestMetas' order, so we record the max seq here
metasMaxSeq := ingestMetas[len(ingestMetas)-1].seq
if err := e.batchIngestSSTs(ingestMetas); err != nil {
e.setError(err)
return
}
seqLock.Lock()
finSeq := finishedSeq.Load()
if metas.seq == finSeq+1 {
finSeq = metas.seq
finMetaSeq := metasMaxSeq
for len(inSyncSeqs.arr) > 0 {
if inSyncSeqs.arr[0].flushSeq == finSeq+1 {
finSeq++
finMetaSeq = inSyncSeqs.arr[0].metaSeq
heap.Remove(inSyncSeqs, 0)
} else {
break
}
}
var flushChans []chan struct{}
for _, seq := range flushQueue {
if seq.seq <= finSeq {
flushChans = append(flushChans, seq.ch)
} else {
break
}
}
flushQueue = flushQueue[len(flushChans):]
finishedSeq.Store(finSeq)
e.finishedMetaSeq.Store(finMetaSeq)
seqLock.Unlock()
for _, c := range flushChans {
c <- struct{}{}
}
} else {
heap.Push(inSyncSeqs, metaSeq{flushSeq: metas.seq, metaSeq: metasMaxSeq})
seqLock.Unlock()
}
}
}
}()
}
compactAndIngestSSTs := func(metas []*sstMeta) {
if len(metas) > 0 {
seqLock.Lock()
metaSeq := seq.Add(1)
seqLock.Unlock()
select {
case <-e.ctx.Done():
case metaChan <- metaAndSeq{metas: metas, seq: metaSeq}:
}
}
}
pendingMetas := make([]*sstMeta, 0, 16)
totalSize := int64(0)
metasTmp := make([]*sstMeta, 0)
addMetas := func() {
if len(metasTmp) == 0 {
return
}
metas := metasTmp
metasTmp = make([]*sstMeta, 0, len(metas))
if !e.config.Compact {
compactAndIngestSSTs(metas)
return
}
for _, m := range metas {
if m.totalCount > 0 {
pendingMetas = append(pendingMetas, m)
totalSize += m.totalSize
if totalSize >= e.config.CompactThreshold {
compactMetas := pendingMetas
pendingMetas = make([]*sstMeta, 0, len(pendingMetas))
totalSize = 0
compactAndIngestSSTs(compactMetas)
}
}
}
}
readMetaLoop:
for {
closed := false
select {
case <-e.ctx.Done():
close(metaChan)
return
case m, ok := <-e.sstMetasChan:
if !ok {
closed = true
break
}
if m.flushCh != nil {
// meet a flush event, we should trigger a ingest task if there are pending metas,
// and then waiting for all the running flush tasks to be done.
if len(metasTmp) > 0 {
addMetas()
}
if len(pendingMetas) > 0 {
seqLock.Lock()
metaSeq := seq.Add(1)
flushQueue = append(flushQueue, flushSeq{ch: m.flushCh, seq: metaSeq})
seqLock.Unlock()
select {
case metaChan <- metaAndSeq{metas: pendingMetas, seq: metaSeq}:
case <-e.ctx.Done():
close(metaChan)
return
}
pendingMetas = make([]*sstMeta, 0, len(pendingMetas))
totalSize = 0
} else {
// none remaining metas needed to be ingested
seqLock.Lock()
curSeq := seq.Load()
finSeq := finishedSeq.Load()
// if all pending SST files are written, directly do a db.Flush
if curSeq == finSeq {
seqLock.Unlock()
m.flushCh <- struct{}{}
} else {
// waiting for pending compaction tasks
flushQueue = append(flushQueue, flushSeq{ch: m.flushCh, seq: curSeq})
seqLock.Unlock()
}
}
continue readMetaLoop
}
metasTmp = append(metasTmp, m.meta)
// try to drain all the sst meta from the chan to make sure all the SSTs are processed before handle a flush msg.
if len(e.sstMetasChan) > 0 {
continue readMetaLoop
}
addMetas()
}
if closed {
compactAndIngestSSTs(pendingMetas)
close(metaChan)
return
}
}
}
func (e *Engine) addSST(ctx context.Context, m *sstMeta) (int32, error) {
// set pending size after SST file is generated
e.pendingFileSize.Add(m.fileSize)
// make sure sstMeta is sent into the chan in order
e.seqLock.Lock()
defer e.seqLock.Unlock()
e.nextSeq++
seq := e.nextSeq
m.seq = seq
select {
case e.sstMetasChan <- metaOrFlush{meta: m}:
case <-ctx.Done():
return 0, ctx.Err()
case <-e.ctx.Done():
}
return seq, e.ingestErr.Get()
}
func (e *Engine) batchIngestSSTs(metas []*sstMeta) error {
if len(metas) == 0 {
return nil
}
slices.SortFunc(metas, func(i, j *sstMeta) bool {
return bytes.Compare(i.minKey, j.minKey) < 0
})
metaLevels := make([][]*sstMeta, 0)
for _, meta := range metas {
inserted := false
for i, l := range metaLevels {
if bytes.Compare(l[len(l)-1].maxKey, meta.minKey) >= 0 {
continue
}
metaLevels[i] = append(l, meta)
inserted = true
break
}
if !inserted {
metaLevels = append(metaLevels, []*sstMeta{meta})
}
}
for _, l := range metaLevels {
if err := e.ingestSSTs(l); err != nil {
return err
}
}
return nil
}
func (e *Engine) ingestSSTs(metas []*sstMeta) error {
// use raw RLock to avoid change the lock state during flushing.
e.mutex.RLock()
defer e.mutex.RUnlock()
if e.closed.Load() {
return errorEngineClosed
}
totalSize := int64(0)
totalCount := int64(0)
fileSize := int64(0)
for _, m := range metas {
totalSize += m.totalSize
totalCount += m.totalCount
fileSize += m.fileSize
}
e.logger.Info("write data to local DB",
zap.Int64("size", totalSize),
zap.Int64("kvs", totalCount),
zap.Int("files", len(metas)),
zap.Int64("sstFileSize", fileSize),
zap.String("file", metas[0].path),
logutil.Key("firstKey", metas[0].minKey),
logutil.Key("lastKey", metas[len(metas)-1].maxKey))
if err := e.sstIngester.ingest(metas); err != nil {
return errors.Trace(err)
}
count := int64(0)
size := int64(0)
for _, m := range metas {
count += m.totalCount
size += m.totalSize
}
e.Length.Add(count)
e.TotalSize.Add(size)
return nil
}
func (e *Engine) flushLocalWriters(parentCtx context.Context) error {
eg, ctx := errgroup.WithContext(parentCtx)
e.localWriters.Range(func(k, v interface{}) bool {
eg.Go(func() error {
w := k.(*Writer)
return w.flush(ctx)
})
return true
})
return eg.Wait()
}
func (e *Engine) flushEngineWithoutLock(ctx context.Context) error {
if err := e.flushLocalWriters(ctx); err != nil {
return err
}
flushChan := make(chan struct{}, 1)
select {
case e.sstMetasChan <- metaOrFlush{flushCh: flushChan}:
case <-ctx.Done():
return ctx.Err()
case <-e.ctx.Done():
return e.ctx.Err()
}
select {
case <-flushChan:
case <-ctx.Done():
return ctx.Err()
case <-e.ctx.Done():
return e.ctx.Err()
}
if err := e.ingestErr.Get(); err != nil {
return errors.Trace(err)
}
if err := e.saveEngineMeta(); err != nil {
return err
}
flushFinishedCh, err := e.db.AsyncFlush()
if err != nil {
return errors.Trace(err)
}
select {
case <-flushFinishedCh:
return nil
case <-ctx.Done():
return ctx.Err()
case <-e.ctx.Done():
return e.ctx.Err()
}
}
func saveEngineMetaToDB(meta *engineMeta, db *pebble.DB) error {
jsonBytes, err := json.Marshal(meta)
if err != nil {
return errors.Trace(err)
}
// note: we can't set Sync to true since we disabled WAL.
return db.Set(engineMetaKey, jsonBytes, &pebble.WriteOptions{Sync: false})
}
// saveEngineMeta saves the metadata about the DB into the DB itself.
// This method should be followed by a Flush to ensure the data is actually synchronized
func (e *Engine) saveEngineMeta() error {
e.logger.Debug("save engine meta", zap.Stringer("uuid", e.UUID), zap.Int64("count", e.Length.Load()),
zap.Int64("size", e.TotalSize.Load()))
return errors.Trace(saveEngineMetaToDB(&e.engineMeta, e.db))
}
func (e *Engine) loadEngineMeta() error {
jsonBytes, closer, err := e.db.Get(engineMetaKey)
if err != nil {
if err == pebble.ErrNotFound {
e.logger.Debug("local db missing engine meta", zap.Stringer("uuid", e.UUID), log.ShortError(err))
return nil
}
return err
}
//nolint: errcheck
defer closer.Close()
if err = json.Unmarshal(jsonBytes, &e.engineMeta); err != nil {
e.logger.Warn("local db failed to deserialize meta", zap.Stringer("uuid", e.UUID), zap.ByteString("content", jsonBytes), zap.Error(err))
return err
}
e.logger.Debug("load engine meta", zap.Stringer("uuid", e.UUID), zap.Int64("count", e.Length.Load()),
zap.Int64("size", e.TotalSize.Load()))
return nil
}
// sortAndMergeRanges sort the ranges and merge range that overlaps with each other into a single range.
func sortAndMergeRanges(ranges []Range) []Range {
if len(ranges) == 0 {
return ranges
}
slices.SortFunc(ranges, func(i, j Range) bool {
return bytes.Compare(i.start, j.start) < 0
})
curEnd := ranges[0].end
i := 0
for j := 1; j < len(ranges); j++ {
if bytes.Compare(curEnd, ranges[j].start) >= 0 {
if bytes.Compare(curEnd, ranges[j].end) < 0 {
curEnd = ranges[j].end
}
} else {
ranges[i].end = curEnd
i++
ranges[i].start = ranges[j].start
curEnd = ranges[j].end
}
}
ranges[i].end = curEnd
return ranges[:i+1]
}
func filterOverlapRange(ranges []Range, finishedRanges []Range) []Range {
if len(ranges) == 0 || len(finishedRanges) == 0 {
return ranges
}
result := make([]Range, 0)
for _, r := range ranges {
start := r.start
end := r.end
for len(finishedRanges) > 0 && bytes.Compare(finishedRanges[0].start, end) < 0 {
fr := finishedRanges[0]
if bytes.Compare(fr.start, start) > 0 {
result = append(result, Range{start: start, end: fr.start})
}
if bytes.Compare(fr.end, start) > 0 {
start = fr.end
}
if bytes.Compare(fr.end, end) > 0 {
break
}
finishedRanges = finishedRanges[1:]
}
if bytes.Compare(start, end) < 0 {
result = append(result, Range{start: start, end: end})
}
}
return result
}
func (e *Engine) unfinishedRanges(ranges []Range) []Range {
e.finishedRanges.Lock()
defer e.finishedRanges.Unlock()
e.finishedRanges.ranges = sortAndMergeRanges(e.finishedRanges.ranges)
return filterOverlapRange(ranges, e.finishedRanges.ranges)
}
func (e *Engine) newKVIter(ctx context.Context, opts *pebble.IterOptions) Iter {
if bytes.Compare(opts.LowerBound, normalIterStartKey) < 0 {
newOpts := *opts
newOpts.LowerBound = normalIterStartKey
opts = &newOpts
}
if !e.duplicateDetection {
return pebbleIter{Iterator: e.db.NewIter(opts)}
}
logger := log.FromContext(ctx).With(
zap.String("table", common.UniqueTable(e.tableInfo.DB, e.tableInfo.Name)),
zap.Int64("tableID", e.tableInfo.ID),
zap.Stringer("engineUUID", e.UUID))
return newDupDetectIter(ctx, e.db, e.keyAdapter, opts, e.duplicateDB, logger)
}
type sstMeta struct {
path string
minKey []byte
maxKey []byte
totalSize int64
totalCount int64
// used for calculate disk-quota
fileSize int64
seq int32
}
type Writer struct {
sync.Mutex
engine *Engine
memtableSizeLimit int64
// if the KVs are append in order, we can directly write the into SST file,
// else we must first store them in writeBatch and then batch flush into SST file.
isKVSorted bool
writer *sstWriter
// bytes buffer for writeBatch
kvBuffer *membuf.Buffer
writeBatch []common.KvPair
// if the kvs in writeBatch are in order, we can avoid doing a `sort.Slice` which
// is quite slow. in our bench, the sort operation eats about 5% of total CPU
isWriteBatchSorted bool
sortedKeyBuf []byte
batchCount int
batchSize int64
lastMetaSeq int32
}
func (w *Writer) appendRowsSorted(kvs []common.KvPair) error {
if w.writer == nil {
writer, err := w.createSSTWriter()
if err != nil {
return errors.Trace(err)
}
w.writer = writer
}
keyAdapter := w.engine.keyAdapter
totalKeySize := 0
for i := 0; i < len(kvs); i++ {
keySize := keyAdapter.EncodedLen(kvs[i].Key)
w.batchSize += int64(keySize + len(kvs[i].Val))
totalKeySize += keySize
}
w.batchCount += len(kvs)
// noopKeyAdapter doesn't really change the key,
// skipping the encoding to avoid unnecessary alloc and copy.
if _, ok := keyAdapter.(noopKeyAdapter); !ok {
if cap(w.sortedKeyBuf) < totalKeySize {
w.sortedKeyBuf = make([]byte, totalKeySize)
}
buf := w.sortedKeyBuf[:0]
newKvs := make([]common.KvPair, len(kvs))
for i := 0; i < len(kvs); i++ {
buf = keyAdapter.Encode(buf, kvs[i].Key, kvs[i].RowID)
newKvs[i] = common.KvPair{Key: buf, Val: kvs[i].Val}
buf = buf[len(buf):]
}
kvs = newKvs
}
return w.writer.writeKVs(kvs)
}
func (w *Writer) appendRowsUnsorted(ctx context.Context, kvs []common.KvPair) error {
l := len(w.writeBatch)
cnt := w.batchCount
var lastKey []byte
if cnt > 0 {
lastKey = w.writeBatch[cnt-1].Key
}
keyAdapter := w.engine.keyAdapter
for _, pair := range kvs {
if w.isWriteBatchSorted && bytes.Compare(lastKey, pair.Key) > 0 {
w.isWriteBatchSorted = false
}
lastKey = pair.Key
w.batchSize += int64(len(pair.Key) + len(pair.Val))
buf := w.kvBuffer.AllocBytes(keyAdapter.EncodedLen(pair.Key))
key := keyAdapter.Encode(buf[:0], pair.Key, pair.RowID)
val := w.kvBuffer.AddBytes(pair.Val)
if cnt < l {
w.writeBatch[cnt].Key = key
w.writeBatch[cnt].Val = val
} else {
w.writeBatch = append(w.writeBatch, common.KvPair{Key: key, Val: val})
}
cnt++
}
w.batchCount = cnt
if w.batchSize > w.memtableSizeLimit {
if err := w.flushKVs(ctx); err != nil {
return err
}
}
return nil
}
func (w *Writer) AppendRows(ctx context.Context, tableName string, columnNames []string, rows kv.Rows) error {
kvs := kv.KvPairsFromRows(rows)
if len(kvs) == 0 {
return nil
}
if w.engine.closed.Load() {
return errorEngineClosed
}
w.Lock()
defer w.Unlock()
// if chunk has _tidb_rowid field, we can't ensure that the rows are sorted.
if w.isKVSorted && w.writer == nil {
for _, c := range columnNames {
if c == model.ExtraHandleName.L {
w.isKVSorted = false
}
}
}
if w.isKVSorted {
return w.appendRowsSorted(kvs)
}
return w.appendRowsUnsorted(ctx, kvs)
}
func (w *Writer) flush(ctx context.Context) error {
w.Lock()
defer w.Unlock()
if w.batchCount == 0 {
return nil
}
if len(w.writeBatch) > 0 {
if err := w.flushKVs(ctx); err != nil {
return errors.Trace(err)
}
}
if w.writer != nil {
meta, err := w.writer.close()
if err != nil {
return errors.Trace(err)
}
w.writer = nil
w.batchCount = 0
if meta != nil && meta.totalSize > 0 {
return w.addSST(ctx, meta)
}
}
return nil
}
type flushStatus struct {
local *Engine
seq int32
}
func (f flushStatus) Flushed() bool {
return f.seq <= f.local.finishedMetaSeq.Load()
}
func (w *Writer) Close(ctx context.Context) (backend.ChunkFlushStatus, error) {
defer w.kvBuffer.Destroy()
defer w.engine.localWriters.Delete(w)
err := w.flush(ctx)
// FIXME: in theory this line is useless, but In our benchmark with go1.15
// this can resolve the memory consistently increasing issue.
// maybe this is a bug related to go GC mechanism.
w.writeBatch = nil
return flushStatus{local: w.engine, seq: w.lastMetaSeq}, err
}
func (w *Writer) IsSynced() bool {
return w.batchCount == 0 && w.lastMetaSeq <= w.engine.finishedMetaSeq.Load()
}
func (w *Writer) flushKVs(ctx context.Context) error {
writer, err := w.createSSTWriter()
if err != nil {
return errors.Trace(err)
}
if !w.isWriteBatchSorted {
slices.SortFunc(w.writeBatch[:w.batchCount], func(i, j common.KvPair) bool {
return bytes.Compare(i.Key, j.Key) < 0
})
w.isWriteBatchSorted = true
}
err = writer.writeKVs(w.writeBatch[:w.batchCount])
if err != nil {
return errors.Trace(err)
}
meta, err := writer.close()
if err != nil {
return errors.Trace(err)
}
err = w.addSST(ctx, meta)
if err != nil {
return errors.Trace(err)
}
w.batchSize = 0
w.batchCount = 0
w.kvBuffer.Reset()
return nil
}
func (w *Writer) addSST(ctx context.Context, meta *sstMeta) error {
seq, err := w.engine.addSST(ctx, meta)
if err != nil {
return err
}
w.lastMetaSeq = seq
return nil
}
func (w *Writer) createSSTWriter() (*sstWriter, error) {
path := filepath.Join(w.engine.sstDir, uuid.New().String()+".sst")
writer, err := newSSTWriter(path)
if err != nil {
return nil, err
}
sw := &sstWriter{sstMeta: &sstMeta{path: path}, writer: writer, logger: w.engine.logger}
return sw, nil
}
var errorUnorderedSSTInsertion = errors.New("inserting KVs into SST without order")
type sstWriter struct {
*sstMeta
writer *sstable.Writer
logger log.Logger
}
func newSSTWriter(path string) (*sstable.Writer, error) {
f, err := os.Create(path)
if err != nil {
return nil, errors.Trace(err)
}
writer := sstable.NewWriter(f, sstable.WriterOptions{
TablePropertyCollectors: []func() pebble.TablePropertyCollector{
newRangePropertiesCollector,
},
BlockSize: 16 * 1024,
})
return writer, nil
}
func (sw *sstWriter) writeKVs(kvs []common.KvPair) error {
if len(kvs) == 0 {
return nil
}
if len(sw.minKey) == 0 {
sw.minKey = append([]byte{}, kvs[0].Key...)
}
if bytes.Compare(kvs[0].Key, sw.maxKey) <= 0 {
return errorUnorderedSSTInsertion
}
internalKey := sstable.InternalKey{
Trailer: uint64(sstable.InternalKeyKindSet),
}
var lastKey []byte
for _, p := range kvs {
if bytes.Equal(p.Key, lastKey) {
sw.logger.Warn("duplicated key found, skip write", logutil.Key("key", p.Key))
continue
}
internalKey.UserKey = p.Key
if err := sw.writer.Add(internalKey, p.Val); err != nil {
return errors.Trace(err)
}
sw.totalSize += int64(len(p.Key)) + int64(len(p.Val))
lastKey = p.Key
}
sw.totalCount += int64(len(kvs))
sw.maxKey = append(sw.maxKey[:0], lastKey...)
return nil
}
func (sw *sstWriter) close() (*sstMeta, error) {
if err := sw.writer.Close(); err != nil {
return nil, errors.Trace(err)
}
meta, err := sw.writer.Metadata()
if err != nil {
return nil, errors.Trace(err)
}
sw.fileSize = int64(meta.Size)
return sw.sstMeta, nil
}
type sstIter struct {
name string
key []byte
val []byte
iter sstable.Iterator
reader *sstable.Reader
valid bool
}
func (i *sstIter) Close() error {
if err := i.iter.Close(); err != nil {
return errors.Trace(err)
}
err := i.reader.Close()
return errors.Trace(err)
}
type sstIterHeap struct {
iters []*sstIter
}
func (h *sstIterHeap) Len() int {
return len(h.iters)
}
func (h *sstIterHeap) Less(i, j int) bool {
return bytes.Compare(h.iters[i].key, h.iters[j].key) < 0
}
func (h *sstIterHeap) Swap(i, j int) {
h.iters[i], h.iters[j] = h.iters[j], h.iters[i]
}
func (h *sstIterHeap) Push(x interface{}) {
h.iters = append(h.iters, x.(*sstIter))
}
func (h *sstIterHeap) Pop() interface{} {
item := h.iters[len(h.iters)-1]
h.iters = h.iters[:len(h.iters)-1]
return item
}
func (h *sstIterHeap) Next() ([]byte, []byte, error) {
for {
if len(h.iters) == 0 {
return nil, nil, nil
}
iter := h.iters[0]
if iter.valid {
iter.valid = false
return iter.key, iter.val, iter.iter.Error()
}
var k *pebble.InternalKey
k, iter.val = iter.iter.Next()
if k != nil {
iter.key = k.UserKey
iter.valid = true
heap.Fix(h, 0)
} else {
err := iter.Close()
heap.Remove(h, 0)
if err != nil {
return nil, nil, errors.Trace(err)
}
}
}
}
// sstIngester is a interface used to merge and ingest SST files.
// it's a interface mainly used for test convenience
type sstIngester interface {
mergeSSTs(metas []*sstMeta, dir string) (*sstMeta, error)
ingest([]*sstMeta) error
}
type dbSSTIngester struct {
e *Engine
}
func (i dbSSTIngester) mergeSSTs(metas []*sstMeta, dir string) (*sstMeta, error) {
if len(metas) == 0 {
return nil, errors.New("sst metas is empty")
} else if len(metas) == 1 {
return metas[0], nil
}
start := time.Now()
newMeta := &sstMeta{
seq: metas[len(metas)-1].seq,
}
mergeIter := &sstIterHeap{
iters: make([]*sstIter, 0, len(metas)),
}
for _, p := range metas {
f, err := os.Open(p.path)
if err != nil {
return nil, errors.Trace(err)
}
reader, err := sstable.NewReader(f, sstable.ReaderOptions{})
if err != nil {
return nil, errors.Trace(err)
}
iter, err := reader.NewIter(nil, nil)
if err != nil {
return nil, errors.Trace(err)
}
key, val := iter.Next()
if key == nil {
continue
}
if iter.Error() != nil {
return nil, errors.Trace(iter.Error())
}
mergeIter.iters = append(mergeIter.iters, &sstIter{
name: p.path,
iter: iter,
key: key.UserKey,
val: val,
reader: reader,
valid: true,
})
newMeta.totalSize += p.totalSize
newMeta.totalCount += p.totalCount
}
heap.Init(mergeIter)
name := filepath.Join(dir, fmt.Sprintf("%s.sst", uuid.New()))
writer, err := newSSTWriter(name)
if err != nil {
return nil, errors.Trace(err)
}
newMeta.path = name
internalKey := sstable.InternalKey{
Trailer: uint64(sstable.InternalKeyKindSet),
}
key, val, err := mergeIter.Next()
if err != nil {
return nil, err
}
if key == nil {
return nil, errors.New("all ssts are empty")
}
newMeta.minKey = append(newMeta.minKey[:0], key...)
lastKey := make([]byte, 0)
for {
if bytes.Equal(lastKey, key) {
i.e.logger.Warn("duplicated key found, skipped", zap.Binary("key", lastKey))
newMeta.totalCount--
newMeta.totalSize -= int64(len(key) + len(val))
goto nextKey
}
internalKey.UserKey = key
err = writer.Add(internalKey, val)
if err != nil {
return nil, err
}
lastKey = append(lastKey[:0], key...)
nextKey:
key, val, err = mergeIter.Next()
if err != nil {
return nil, err
}
if key == nil {
break
}
}
err = writer.Close()
if err != nil {
return nil, errors.Trace(err)
}
meta, err := writer.Metadata()
if err != nil {
return nil, errors.Trace(err)
}
newMeta.maxKey = lastKey
newMeta.fileSize = int64(meta.Size)
dur := time.Since(start)
i.e.logger.Info("compact sst", zap.Int("fileCount", len(metas)), zap.Int64("size", newMeta.totalSize),
zap.Int64("count", newMeta.totalCount), zap.Duration("cost", dur), zap.String("file", name))
// async clean raw SSTs.
go func() {
totalSize := int64(0)
for _, m := range metas {
totalSize += m.fileSize
if err := os.Remove(m.path); err != nil {
i.e.logger.Warn("async cleanup sst file failed", zap.Error(err))
}
}
// decrease the pending size after clean up
i.e.pendingFileSize.Sub(totalSize)
}()
return newMeta, err
}
func (i dbSSTIngester) ingest(metas []*sstMeta) error {
if len(metas) == 0 {
return nil
}
paths := make([]string, 0, len(metas))
for _, m := range metas {
paths = append(paths, m.path)
}
if i.e.db == nil {
return errorEngineClosed
}
return i.e.db.Ingest(paths)
}
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