tidb metafile 源码
tidb metafile 代码
文件路径：/br/pkg/metautil/metafile.go
// Copyright 2021 PingCAP, Inc. Licensed under Apache-2.0.
package metautil
import (
"bytes"
"context"
"crypto/rand"
"crypto/sha256"
"encoding/json"
"fmt"
"sync"
"time"
"github.com/docker/go-units"
"github.com/gogo/protobuf/proto"
"github.com/opentracing/opentracing-go"
"github.com/pingcap/errors"
backuppb "github.com/pingcap/kvproto/pkg/brpb"
"github.com/pingcap/kvproto/pkg/encryptionpb"
"github.com/pingcap/log"
berrors "github.com/pingcap/tidb/br/pkg/errors"
"github.com/pingcap/tidb/br/pkg/logutil"
"github.com/pingcap/tidb/br/pkg/storage"
"github.com/pingcap/tidb/br/pkg/summary"
"github.com/pingcap/tidb/parser/model"
"github.com/pingcap/tidb/statistics/handle"
"github.com/pingcap/tidb/tablecodec"
"github.com/pingcap/tidb/util/encrypt"
"go.uber.org/zap"
)
const (
// LockFile represents file name
LockFile = "backup.lock"
// MetaFile represents file name
MetaFile = "backupmeta"
// MetaJSONFile represents backup meta json file name
MetaJSONFile = "backupmeta.json"
// MaxBatchSize represents the internal channel buffer size of MetaWriter and MetaReader.
MaxBatchSize = 1024
// MetaFileSize represents the limit size of one MetaFile
MetaFileSize = 128 * units.MiB
// CrypterIvLen represents the length of iv of crypter method
CrypterIvLen = 16
)
const (
// MetaV1 represents the old version of backupmeta.
// because the old version doesn't have version field, so set it to 0 for compatibility.
MetaV1 = iota
// MetaV2 represents the new version of backupmeta.
MetaV2
)
// CreateMetaFileName is the name of meta file.
func CreateMetaFileName(ts uint64) string {
return fmt.Sprintf("%s_%d", MetaFile, ts)
}
// Encrypt encrypts the content according to CipherInfo.
func Encrypt(content []byte, cipher *backuppb.CipherInfo) (encryptedContent, iv []byte, err error) {
if len(content) == 0 || cipher == nil {
return content, iv, nil
}
switch cipher.CipherType {
case encryptionpb.EncryptionMethod_PLAINTEXT:
return content, iv, nil
case encryptionpb.EncryptionMethod_AES128_CTR,
encryptionpb.EncryptionMethod_AES192_CTR,
encryptionpb.EncryptionMethod_AES256_CTR:
// generate random iv for aes crypter
iv = make([]byte, CrypterIvLen)
_, err = rand.Read(iv)
if err != nil {
return content, iv, errors.Trace(err)
}
encryptedContent, err = encrypt.AESEncryptWithCTR(content, cipher.CipherKey, iv)
return
default:
return content, iv, errors.Annotate(berrors.ErrInvalidArgument, "cipher type invalid")
}
}
// Decrypt decrypts the content according to CipherInfo and IV.
func Decrypt(content []byte, cipher *backuppb.CipherInfo, iv []byte) ([]byte, error) {
if len(content) == 0 || cipher == nil {
return content, nil
}
switch cipher.CipherType {
case encryptionpb.EncryptionMethod_PLAINTEXT:
return content, nil
case encryptionpb.EncryptionMethod_AES128_CTR,
encryptionpb.EncryptionMethod_AES192_CTR,
encryptionpb.EncryptionMethod_AES256_CTR:
return encrypt.AESDecryptWithCTR(content, cipher.CipherKey, iv)
default:
return content, errors.Annotate(berrors.ErrInvalidArgument, "cipher type invalid")
}
}
func walkLeafMetaFile(
ctx context.Context,
storage storage.ExternalStorage,
file *backuppb.MetaFile,
cipher *backuppb.CipherInfo,
output func(*backuppb.MetaFile)) error {
if file == nil {
return nil
}
if len(file.MetaFiles) == 0 {
output(file)
return nil
}
for _, node := range file.MetaFiles {
content, err := storage.ReadFile(ctx, node.Name)
if err != nil {
return errors.Trace(err)
}
decryptContent, err := Decrypt(content, cipher, node.CipherIv)
if err != nil {
return errors.Trace(err)
}
checksum := sha256.Sum256(decryptContent)
if !bytes.Equal(node.Sha256, checksum[:]) {
return errors.Annotatef(berrors.ErrInvalidMetaFile,
"checksum mismatch expect %x, got %x", node.Sha256, checksum[:])
}
child := &backuppb.MetaFile{}
if err = proto.Unmarshal(decryptContent, child); err != nil {
return errors.Trace(err)
}
if err = walkLeafMetaFile(ctx, storage, child, cipher, output); err != nil {
return errors.Trace(err)
}
}
return nil
}
// Table wraps the schema and files of a table.
type Table struct {
DB *model.DBInfo
Info *model.TableInfo
Crc64Xor uint64
TotalKvs uint64
TotalBytes uint64
Files []*backuppb.File
TiFlashReplicas int
Stats *handle.JSONTable
}
// NoChecksum checks whether the table has a calculated checksum.
func (tbl *Table) NoChecksum() bool {
return tbl.Crc64Xor == 0 && tbl.TotalKvs == 0 && tbl.TotalBytes == 0
}
// MetaReader wraps a reader to read both old and new version of backupmeta.
type MetaReader struct {
storage storage.ExternalStorage
backupMeta *backuppb.BackupMeta
cipher *backuppb.CipherInfo
}
// NewMetaReader creates MetaReader.
func NewMetaReader(
backpMeta *backuppb.BackupMeta,
storage storage.ExternalStorage,
cipher *backuppb.CipherInfo) *MetaReader {
return &MetaReader{
storage: storage,
backupMeta: backpMeta,
cipher: cipher,
}
}
func (reader *MetaReader) readDDLs(ctx context.Context, output func([]byte)) error {
// Read backupmeta v1 metafiles.
// if the backupmeta equals to v1, or doesn't not exists(old version).
if reader.backupMeta.Version == MetaV1 {
output(reader.backupMeta.Ddls)
return nil
}
// Read backupmeta v2 metafiles.
outputFn := func(m *backuppb.MetaFile) {
for _, s := range m.Ddls {
output(s)
}
}
return walkLeafMetaFile(ctx, reader.storage, reader.backupMeta.DdlIndexes, reader.cipher, outputFn)
}
func (reader *MetaReader) readSchemas(ctx context.Context, output func(*backuppb.Schema)) error {
// Read backupmeta v1 metafiles.
for _, s := range reader.backupMeta.Schemas {
output(s)
}
// Read backupmeta v2 metafiles.
outputFn := func(m *backuppb.MetaFile) {
for _, s := range m.Schemas {
output(s)
}
}
return walkLeafMetaFile(ctx, reader.storage, reader.backupMeta.SchemaIndex, reader.cipher, outputFn)
}
func (reader *MetaReader) readDataFiles(ctx context.Context, output func(*backuppb.File)) error {
// Read backupmeta v1 data files.
for _, f := range reader.backupMeta.Files {
output(f)
}
// Read backupmeta v2 data files.
outputFn := func(m *backuppb.MetaFile) {
for _, f := range m.DataFiles {
output(f)
}
}
return walkLeafMetaFile(ctx, reader.storage, reader.backupMeta.FileIndex, reader.cipher, outputFn)
}
// ArchiveSize return the size of Archive data
func (*MetaReader) ArchiveSize(_ context.Context, files []*backuppb.File) uint64 {
total := uint64(0)
for _, file := range files {
total += file.Size_
}
return total
}
// ReadDDLs reads the ddls from the backupmeta.
// This function is compatible with the old backupmeta.
func (reader *MetaReader) ReadDDLs(ctx context.Context) ([]byte, error) {
var err error
ch := make(chan interface{}, MaxBatchSize)
errCh := make(chan error)
go func() {
if err = reader.readDDLs(ctx, func(s []byte) { ch <- s }); err != nil {
errCh <- errors.Trace(err)
}
close(ch)
}()
var ddlBytes []byte
var ddlBytesArray [][]byte
for {
itemCount := 0
err := receiveBatch(ctx, errCh, ch, MaxBatchSize, func(item interface{}) error {
itemCount++
if reader.backupMeta.Version == MetaV1 {
ddlBytes = item.([]byte)
} else {
// we collect all ddls from files.
ddlBytesArray = append(ddlBytesArray, item.([]byte))
}
return nil
})
if err != nil {
return nil, errors.Trace(err)
}
// finish read
if itemCount == 0 {
if len(ddlBytesArray) != 0 {
ddlBytes = mergeDDLs(ddlBytesArray)
}
return ddlBytes, nil
}
}
}
// ReadSchemasFiles reads the schema and datafiles from the backupmeta.
// This function is compatible with the old backupmeta.
func (reader *MetaReader) ReadSchemasFiles(ctx context.Context, output chan<- *Table) error {
ch := make(chan interface{}, MaxBatchSize)
errCh := make(chan error, 1)
go func() {
if err := reader.readSchemas(ctx, func(s *backuppb.Schema) { ch <- s }); err != nil {
errCh <- errors.Trace(err)
}
close(ch)
}()
// It's not easy to balance memory and time costs for current structure.
// put all files in memory due to https://github.com/pingcap/br/issues/705
fileMap := make(map[int64][]*backuppb.File)
outputFn := func(file *backuppb.File) {
tableID := tablecodec.DecodeTableID(file.GetStartKey())
if tableID == 0 {
log.Panic("tableID must not equal to 0", logutil.File(file))
}
fileMap[tableID] = append(fileMap[tableID], file)
}
err := reader.readDataFiles(ctx, outputFn)
if err != nil {
return errors.Trace(err)
}
for {
// table ID -> *Table
tableMap := make(map[int64]*Table, MaxBatchSize)
err := receiveBatch(ctx, errCh, ch, MaxBatchSize, func(item interface{}) error {
s := item.(*backuppb.Schema)
dbInfo := &model.DBInfo{}
if err := json.Unmarshal(s.Db, dbInfo); err != nil {
return errors.Trace(err)
}
var tableInfo *model.TableInfo
if s.Table != nil {
tableInfo = &model.TableInfo{}
if err := json.Unmarshal(s.Table, tableInfo); err != nil {
return errors.Trace(err)
}
}
var stats *handle.JSONTable
if s.Stats != nil {
stats = &handle.JSONTable{}
if err := json.Unmarshal(s.Stats, stats); err != nil {
return errors.Trace(err)
}
}
table := &Table{
DB: dbInfo,
Info: tableInfo,
Crc64Xor: s.Crc64Xor,
TotalKvs: s.TotalKvs,
TotalBytes: s.TotalBytes,
TiFlashReplicas: int(s.TiflashReplicas),
Stats: stats,
}
if tableInfo != nil {
if files, ok := fileMap[tableInfo.ID]; ok {
table.Files = append(table.Files, files...)
}
if tableInfo.Partition != nil {
// Partition table can have many table IDs (partition IDs).
for _, p := range tableInfo.Partition.Definitions {
if files, ok := fileMap[p.ID]; ok {
table.Files = append(table.Files, files...)
}
}
}
tableMap[tableInfo.ID] = table
} else {
// empty database
tableMap[dbInfo.ID] = table
}
return nil
})
if err != nil {
return errors.Trace(err)
}
if len(tableMap) == 0 {
// We have read all tables.
return nil
}
for _, table := range tableMap {
output <- table
}
}
}
func receiveBatch(
ctx context.Context, errCh chan error, ch <-chan interface{}, maxBatchSize int,
collectItem func(interface{}) error,
) error {
batchSize := 0
for {
select {
case <-ctx.Done():
return errors.Trace(ctx.Err())
case err := <-errCh:
return errors.Trace(err)
case s, ok := <-ch:
if !ok {
return nil
}
if err := collectItem(s); err != nil {
return errors.Trace(err)
}
}
// Return if the batch is large enough.
batchSize++
if batchSize >= maxBatchSize {
return nil
}
}
}
// AppendOp represents the operation type of meta.
type AppendOp int
const (
// AppendMetaFile represents the MetaFile type.
AppendMetaFile AppendOp = 0
// AppendDataFile represents the DataFile type.
// it records the file meta from tikv.
AppendDataFile AppendOp = 1
// AppendSchema represents the schema from tidb.
AppendSchema AppendOp = 2
// AppendDDL represents the ddls before last backup.
AppendDDL AppendOp = 3
)
func (op AppendOp) name() string {
var name string
switch op {
case AppendMetaFile:
name = "metafile"
case AppendDataFile:
name = "datafile"
case AppendSchema:
name = "schema"
case AppendDDL:
name = "ddl"
default:
log.Panic("unsupport op type", zap.Any("op", op))
}
return name
}
// appends item to MetaFile
func (op AppendOp) appendFile(a *backuppb.MetaFile, b interface{}) (dataFileSize int, size int, itemCount int) {
switch op {
case AppendMetaFile:
metaFile := b.(*backuppb.File)
a.MetaFiles = append(a.MetaFiles, metaFile)
size += metaFile.Size()
itemCount++
case AppendDataFile:
// receive a batch of file because we need write and default sst are adjacent.
files := b.([]*backuppb.File)
a.DataFiles = append(a.DataFiles, files...)
for _, f := range files {
itemCount++
size += f.Size()
dataFileSize += int(f.Size_)
}
case AppendSchema:
a.Schemas = append(a.Schemas, b.(*backuppb.Schema))
itemCount++
size += b.(*backuppb.Schema).Size()
case AppendDDL:
a.Ddls = append(a.Ddls, b.([]byte))
itemCount++
size += len(b.([]byte))
}
return dataFileSize, size, itemCount
}
type sizedMetaFile struct {
// A stack like array, we always append to the last node.
root *backuppb.MetaFile
dataFileSize int
size int
itemNum int
sizeLimit int
}
// NewSizedMetaFile represents the sizedMetaFile.
func NewSizedMetaFile(sizeLimit int) *sizedMetaFile {
return &sizedMetaFile{
root: &backuppb.MetaFile{
Schemas: make([]*backuppb.Schema, 0),
DataFiles: make([]*backuppb.File, 0),
RawRanges: make([]*backuppb.RawRange, 0),
},
sizeLimit: sizeLimit,
}
}
func (f *sizedMetaFile) append(file interface{}, op AppendOp) bool {
// append to root
// TODO maybe use multi level index
dataFileSize, size, itemCount := op.appendFile(f.root, file)
f.itemNum += itemCount
f.size += size
f.dataFileSize += dataFileSize
// f.size would reset outside
return f.size > f.sizeLimit
}
// MetaWriter represents wraps a writer, and the MetaWriter should be compatible with old version of backupmeta.
type MetaWriter struct {
storage storage.ExternalStorage
metafileSizeLimit int
// a flag to control whether we generate v1 or v2 meta.
useV2Meta bool
backupMeta *backuppb.BackupMeta
// used to generate MetaFile name.
metafileSizes map[string]int
metafileSeqNum map[string]int
metafiles *sizedMetaFile
// the start time of StartWriteMetas
// it's use to calculate the time costs.
start time.Time
// wg waits StartWriterMetas exits
wg sync.WaitGroup
// internal item channel
metasCh chan interface{}
errCh chan error
// records the total item of in one write meta job.
flushedItemNum int
// the filename that backupmeta has flushed into.
metaFileName string
cipher *backuppb.CipherInfo
// records the total datafile size
totalDataFileSize int
}
// NewMetaWriter creates MetaWriter.
func NewMetaWriter(
storage storage.ExternalStorage,
metafileSizeLimit int,
useV2Meta bool,
metaFileName string,
cipher *backuppb.CipherInfo,
) *MetaWriter {
if len(metaFileName) == 0 {
metaFileName = MetaFile
}
return &MetaWriter{
start: time.Now(),
storage: storage,
metafileSizeLimit: metafileSizeLimit,
useV2Meta: useV2Meta,
// keep the compatibility for old backupmeta.Ddls
// old version: Ddls, _ := json.Marshal(make([]*model.Job, 0))
backupMeta: &backuppb.BackupMeta{Ddls: []byte("[]")},
metafileSizes: make(map[string]int),
metafiles: NewSizedMetaFile(metafileSizeLimit),
metafileSeqNum: make(map[string]int),
metaFileName: metaFileName,
cipher: cipher,
}
}
func (writer *MetaWriter) reset() {
writer.metasCh = make(chan interface{}, MaxBatchSize)
writer.errCh = make(chan error)
// reset flushedItemNum for next meta.
writer.flushedItemNum = 0
}
// Update updates some property of backupmeta.
func (writer *MetaWriter) Update(f func(m *backuppb.BackupMeta)) {
f(writer.backupMeta)
}
// Send sends the item to buffer.
func (writer *MetaWriter) Send(m interface{}, _ AppendOp) error {
select {
case writer.metasCh <- m:
// receive an error from StartWriteMetasAsync
case err := <-writer.errCh:
return errors.Trace(err)
}
return nil
}
func (writer *MetaWriter) close() {
close(writer.metasCh)
}
// StartWriteMetasAsync writes four kind of meta into backupmeta.
// 1. file
// 2. schema
// 3. ddl
// 4. rawRange( raw kv )
// when useBackupMetaV2 enabled, it will generate multi-level index backupmetav2.
// else it will generate backupmeta as before for compatibility.
// User should call FinishWriteMetas after StartWriterMetasAsync.
func (writer *MetaWriter) StartWriteMetasAsync(ctx context.Context, op AppendOp) {
writer.reset()
writer.start = time.Now()
writer.wg.Add(1)
go func() {
defer func() {
close(writer.errCh)
// close errCh before metaCh closed
writer.wg.Done()
}()
for {
select {
case <-ctx.Done():
log.Info("exit write metas by context done")
return
case meta, ok := <-writer.metasCh:
if !ok {
log.Info("write metas finished", zap.String("type", op.name()))
return
}
needFlush := writer.metafiles.append(meta, op)
if writer.useV2Meta && needFlush {
err := writer.flushMetasV2(ctx, op)
if err != nil {
writer.errCh <- err
}
}
}
}
}()
}
// FinishWriteMetas close the channel in StartWriteMetasAsync and flush the buffered data.
func (writer *MetaWriter) FinishWriteMetas(ctx context.Context, op AppendOp) error {
writer.close()
// always start one goroutine to write one kind of meta.
writer.wg.Wait()
if span := opentracing.SpanFromContext(ctx); span != nil && span.Tracer() != nil {
span1 := span.Tracer().StartSpan("MetaWriter.Finish", opentracing.ChildOf(span.Context()))
defer span1.Finish()
ctx = opentracing.ContextWithSpan(ctx, span1)
}
var err error
// flush the buffered meta
if !writer.useV2Meta {
writer.fillMetasV1(ctx, op)
} else {
err = writer.flushMetasV2(ctx, op)
if err != nil {
return errors.Trace(err)
}
}
costs := time.Since(writer.start)
if op == AppendDataFile {
summary.CollectSuccessUnit("backup ranges", writer.flushedItemNum, costs)
}
log.Info("finish the write metas", zap.Int("item", writer.flushedItemNum),
zap.String("type", op.name()), zap.Duration("costs", costs))
return nil
}
// FlushBackupMeta flush the `backupMeta` to `ExternalStorage`
func (writer *MetaWriter) FlushBackupMeta(ctx context.Context) error {
// Set schema version
if writer.useV2Meta {
writer.backupMeta.Version = MetaV2
} else {
writer.backupMeta.Version = MetaV1
}
// Flush the writer.backupMeta to storage
backupMetaData, err := proto.Marshal(writer.backupMeta)
if err != nil {
return errors.Trace(err)
}
log.Debug("backup meta", zap.Reflect("meta", writer.backupMeta))
log.Info("save backup meta", zap.Int("size", len(backupMetaData)))
encryptBuff, iv, err := Encrypt(backupMetaData, writer.cipher)
if err != nil {
return errors.Trace(err)
}
return writer.storage.WriteFile(ctx, writer.metaFileName, append(iv, encryptBuff...))
}
// fillMetasV1 keep the compatibility for old version.
// for MetaV1, just put in backupMeta
func (writer *MetaWriter) fillMetasV1(_ context.Context, op AppendOp) {
switch op {
case AppendDataFile:
writer.backupMeta.Files = writer.metafiles.root.DataFiles
case AppendSchema:
writer.backupMeta.Schemas = writer.metafiles.root.Schemas
case AppendDDL:
writer.backupMeta.Ddls = mergeDDLs(writer.metafiles.root.Ddls)
default:
log.Panic("unsupport op type", zap.Any("op", op))
}
writer.flushedItemNum += writer.metafiles.itemNum
}
func (writer *MetaWriter) flushMetasV2(ctx context.Context, op AppendOp) error {
var index *backuppb.MetaFile
switch op {
case AppendSchema:
if len(writer.metafiles.root.Schemas) == 0 {
return nil
}
// Add the metafile to backupmeta and reset metafiles.
if writer.backupMeta.SchemaIndex == nil {
writer.backupMeta.SchemaIndex = &backuppb.MetaFile{}
}
index = writer.backupMeta.SchemaIndex
case AppendDataFile:
if len(writer.metafiles.root.DataFiles) == 0 {
return nil
}
// Add the metafile to backupmeta and reset metafiles.
if writer.backupMeta.FileIndex == nil {
writer.backupMeta.FileIndex = &backuppb.MetaFile{}
}
index = writer.backupMeta.FileIndex
case AppendDDL:
if len(writer.metafiles.root.Ddls) == 0 {
return nil
}
if writer.backupMeta.DdlIndexes == nil {
writer.backupMeta.DdlIndexes = &backuppb.MetaFile{}
}
index = writer.backupMeta.DdlIndexes
}
content, err := writer.metafiles.root.Marshal()
if err != nil {
return errors.Trace(err)
}
name := op.name()
writer.metafileSizes[name] += writer.metafiles.size
writer.totalDataFileSize += writer.metafiles.dataFileSize
// Flush metafiles to external storage.
writer.metafileSeqNum["metafiles"]++
fname := fmt.Sprintf("backupmeta.%s.%09d", name, writer.metafileSeqNum["metafiles"])
encyptedContent, iv, err := Encrypt(content, writer.cipher)
if err != nil {
return errors.Trace(err)
}
if err = writer.storage.WriteFile(ctx, fname, encyptedContent); err != nil {
return errors.Trace(err)
}
checksum := sha256.Sum256(content)
file := &backuppb.File{
Name: fname,
Sha256: checksum[:],
Size_: uint64(len(content)),
CipherIv: iv,
}
index.MetaFiles = append(index.MetaFiles, file)
writer.flushedItemNum += writer.metafiles.itemNum
writer.metafiles = NewSizedMetaFile(writer.metafiles.sizeLimit)
return nil
}
// ArchiveSize represents the size of ArchiveSize.
func (writer *MetaWriter) ArchiveSize() uint64 {
total := uint64(0)
for _, file := range writer.backupMeta.Files {
total += file.Size_
}
total += uint64(writer.totalDataFileSize)
return total
}
// Backupmeta clones a backupmeta.
func (writer *MetaWriter) Backupmeta() *backuppb.BackupMeta {
clone := proto.Clone(writer.backupMeta)
return clone.(*backuppb.BackupMeta)
}
func mergeDDLs(ddls [][]byte) []byte {
b := bytes.Join(ddls, []byte(`,`))
b = append(b, 0)
copy(b[1:], b[0:])
b[0] = byte('[')
b = append(b, ']')
return b
}
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