498 lines
12 KiB
Go
498 lines
12 KiB
Go
package atree
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import (
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"errors"
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"fmt"
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"os"
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"path/filepath"
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"sync"
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diploma "gordenko.dev/dima/qb"
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"gordenko.dev/dima/qb/atree/redo"
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"gordenko.dev/dima/qb/bin"
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)
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const (
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filePerm = 0770
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// index page
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indexRecordsQtyIdx = IndexPageSize - 7
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isDataPageNumbersIdx = IndexPageSize - 5
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indexCRC32Idx = IndexPageSize - 4
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// data page
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timestampsSizeIdx = DataPageSize - 12
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valuesSizeIdx = DataPageSize - 10
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prevPageIdx = DataPageSize - 8
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dataCRC32Idx = DataPageSize - 4
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timestampSize = 4
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pairSize = timestampSize + PageNoSize
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indexFooterIdx = indexRecordsQtyIdx
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dataFooterIdx = timestampsSizeIdx
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DataPageSize = 8192
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IndexPageSize = 1024
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PageNoSize = 4
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//
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DataPagePayloadSize int = dataFooterIdx
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)
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type FreeList interface {
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ReservePage() uint32
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}
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type _page struct {
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PageNo uint32
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Buf []byte
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ReferenceCount int
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}
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type Atree struct {
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redoDir string
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indexFreelist FreeList
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dataFreelist FreeList
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dataFile *os.File
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indexFile *os.File
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mutex sync.Mutex
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allocatedIndexPagesQty uint32
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allocatedDataPagesQty uint32
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indexPages map[uint32]*_page
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dataPages map[uint32]*_page
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indexWaits map[uint32][]chan readResult
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dataWaits map[uint32][]chan readResult
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indexPagesToRead []uint32
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dataPagesToRead []uint32
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readSignalCh chan struct{}
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writeSignalCh chan struct{}
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writeTasksQueue []WriteTask
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}
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type Options struct {
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Dir string
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RedoDir string
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DatabaseName string
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DataFreeList FreeList
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IndexFreeList FreeList
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}
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func New(opt Options) (*Atree, error) {
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if opt.Dir == "" {
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return nil, errors.New("Dir option is required")
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}
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if opt.RedoDir == "" {
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return nil, errors.New("RedoDir option is required")
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}
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if opt.DatabaseName == "" {
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return nil, errors.New("DatabaseName option is required")
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}
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if opt.DataFreeList == nil {
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return nil, errors.New("DataFreeList option is required")
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}
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if opt.IndexFreeList == nil {
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return nil, errors.New("IndexFreeList option is required")
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}
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// открываю или создаю dbName.data и dbName.index файлы
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var (
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indexFileName = filepath.Join(opt.Dir, opt.DatabaseName+".index")
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dataFileName = filepath.Join(opt.Dir, opt.DatabaseName+".data")
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indexFile *os.File
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dataFile *os.File
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allocatedIndexPagesQty uint32
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allocatedDataPagesQty uint32
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)
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// При создании data файла сразу создается индекс, поэтому корректное
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// состояние БД: либо оба файла есть, либо ни одного файла нет.
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isIndexExist, err := isFileExist(indexFileName)
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if err != nil {
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return nil, fmt.Errorf("check index file is exist: %s", err)
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}
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isDataExist, err := isFileExist(dataFileName)
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if err != nil {
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return nil, fmt.Errorf("check data file is exist: %s", err)
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}
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if isIndexExist {
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if isDataExist {
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// открываю оба файла
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indexFile, allocatedIndexPagesQty, err = openFile(indexFileName, IndexPageSize)
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if err != nil {
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return nil, fmt.Errorf("open index file: %s", err)
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}
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dataFile, allocatedDataPagesQty, err = openFile(dataFileName, DataPageSize)
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if err != nil {
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return nil, fmt.Errorf("open data file: %s", err)
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}
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} else {
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// нет data файла
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return nil, errors.New("not found data file")
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}
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} else {
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if isDataExist {
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// index файла нет
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return nil, errors.New("not found index file")
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} else {
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// нет обоих файлов
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indexFile, err = os.OpenFile(indexFileName, os.O_CREATE|os.O_RDWR, filePerm)
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if err != nil {
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return nil, err
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}
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dataFile, err = os.OpenFile(dataFileName, os.O_CREATE|os.O_RDWR, filePerm)
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if err != nil {
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return nil, err
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}
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}
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}
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tree := &Atree{
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redoDir: opt.RedoDir,
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indexFreelist: opt.IndexFreeList,
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dataFreelist: opt.DataFreeList,
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indexFile: indexFile,
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dataFile: dataFile,
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allocatedIndexPagesQty: allocatedIndexPagesQty,
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allocatedDataPagesQty: allocatedDataPagesQty,
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indexPages: make(map[uint32]*_page),
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dataPages: make(map[uint32]*_page),
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indexWaits: make(map[uint32][]chan readResult),
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dataWaits: make(map[uint32][]chan readResult),
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readSignalCh: make(chan struct{}, 1),
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writeSignalCh: make(chan struct{}, 1),
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}
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return tree, nil
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}
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func (s *Atree) Run() {
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go s.pageWriter()
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go s.pageReader()
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}
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// FIND
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func (s *Atree) findDataPage(rootPageNo uint32, timestamp uint32) (uint32, []byte, error) {
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indexPageNo := rootPageNo
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for {
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buf, err := s.fetchIndexPage(indexPageNo)
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if err != nil {
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return 0, nil, fmt.Errorf("fetchIndexPage(%d): %s", indexPageNo, err)
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}
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foundPageNo := findPageNo(buf, timestamp)
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s.releaseIndexPage(indexPageNo)
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if buf[isDataPageNumbersIdx] == 1 {
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buf, err := s.fetchDataPage(foundPageNo)
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if err != nil {
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return 0, nil, fmt.Errorf("fetchDataPage(%d): %s", foundPageNo, err)
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}
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return foundPageNo, buf, nil
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}
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// вглубь
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indexPageNo = foundPageNo
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}
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}
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type pathLeg struct {
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PageNo uint32
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Data []byte
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}
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type pathToDataPage struct {
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Legs []pathLeg
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LastPageNo uint32
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}
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func (s *Atree) findPathToLastPage(rootPageNo uint32) (_ pathToDataPage, err error) {
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var (
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pageNo = rootPageNo
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legs []pathLeg
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)
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for {
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var buf []byte
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buf, err = s.fetchIndexPage(pageNo)
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if err != nil {
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err = fmt.Errorf("FetchIndexPage(%d): %s", pageNo, err)
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return
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}
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legs = append(legs, pathLeg{
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PageNo: pageNo,
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Data: buf,
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// childIdx не нужен
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})
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foundPageNo := getLastPageNo(buf)
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if buf[isDataPageNumbersIdx] == 1 {
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return pathToDataPage{
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Legs: legs,
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LastPageNo: foundPageNo,
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}, nil
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}
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// вглубь
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pageNo = foundPageNo
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}
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}
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// APPEND DATA PAGE
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type AppendDataPageReq struct {
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MetricID uint32
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Timestamp uint32
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Value float64
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Since uint32
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RootPageNo uint32
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PrevPageNo uint32
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TimestampsChunks [][]byte
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TimestampsSize uint16
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ValuesChunks [][]byte
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ValuesSize uint16
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}
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func (s *Atree) AppendDataPage(req AppendDataPageReq) (_ redo.Report, err error) {
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var (
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flags byte
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dataPagesToRelease []uint32
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indexPagesToRelease []uint32
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)
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newDataPage := s.allocDataPage()
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dataPagesToRelease = append(dataPagesToRelease, newDataPage.PageNo)
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chunksToDataPage(newDataPage.Data, chunksToDataPageReq{
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PrevPageNo: req.PrevPageNo,
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TimestampsChunks: req.TimestampsChunks,
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TimestampsSize: req.TimestampsSize,
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ValuesChunks: req.ValuesChunks,
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ValuesSize: req.ValuesSize,
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})
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redoWriter, err := redo.NewWriter(redo.WriterOptions{
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Dir: s.redoDir,
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MetricID: req.MetricID,
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Timestamp: req.Timestamp,
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Value: req.Value,
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IsDataPageReused: newDataPage.IsReused,
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DataPageNo: newDataPage.PageNo,
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Page: newDataPage.Data,
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})
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if err != nil {
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return
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}
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if req.RootPageNo > 0 {
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var path pathToDataPage
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path, err = s.findPathToLastPage(req.RootPageNo)
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if err != nil {
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return
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}
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for _, leg := range path.Legs {
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indexPagesToRelease = append(indexPagesToRelease, leg.PageNo)
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}
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if path.LastPageNo != req.PrevPageNo {
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diploma.Abort(
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diploma.WrongPrevPageNo,
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fmt.Errorf("bug: last pageNo %d in tree != prev pageNo %d in _metric",
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path.LastPageNo, req.PrevPageNo),
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)
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}
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newPageNo := newDataPage.PageNo
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lastIdx := len(path.Legs) - 1
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for legIdx := lastIdx; legIdx >= 0; legIdx-- {
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leg := path.Legs[legIdx]
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ok := appendPair(leg.Data, req.Since, newPageNo)
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if ok {
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err = redoWriter.AppendIndexPage(leg.PageNo, leg.Data, 0)
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if err != nil {
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return
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}
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break
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}
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newIndexPage := s.allocIndexPage()
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indexPagesToRelease = append(indexPagesToRelease, newIndexPage.PageNo)
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appendPair(newIndexPage.Data, req.Since, newPageNo)
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// ставлю мітку що всі pageNo на сторінці - це data pageNo
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if legIdx == lastIdx {
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newIndexPage.Data[isDataPageNumbersIdx] = 1
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}
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flags = 0
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if newIndexPage.IsReused {
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flags |= redo.FlagReused
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}
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err = redoWriter.AppendIndexPage(newIndexPage.PageNo, newIndexPage.Data, flags)
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if err != nil {
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return
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}
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//
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newPageNo = newIndexPage.PageNo
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if legIdx == 0 {
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newRoot := s.allocIndexPage()
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indexPagesToRelease = append(indexPagesToRelease, newRoot.PageNo)
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appendPair(newRoot.Data, getSince(leg.Data), leg.PageNo) // old rootPageNo
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appendPair(newRoot.Data, req.Since, newIndexPage.PageNo)
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// Фиксирую новый root в REDO логе
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flags = redo.FlagNewRoot
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if newRoot.IsReused {
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flags |= redo.FlagReused
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}
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err = redoWriter.AppendIndexPage(newRoot.PageNo, newRoot.Data, flags)
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if err != nil {
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return
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}
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break
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}
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}
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} else {
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newRoot := s.allocIndexPage()
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indexPagesToRelease = append(indexPagesToRelease, newRoot.PageNo)
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newRoot.Data[isDataPageNumbersIdx] = 1
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appendPair(newRoot.Data, req.Since, newDataPage.PageNo)
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flags = redo.FlagNewRoot
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if newRoot.IsReused {
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flags |= redo.FlagReused
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}
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err = redoWriter.AppendIndexPage(newRoot.PageNo, newRoot.Data, flags)
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if err != nil {
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return
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}
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}
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err = redoWriter.Close()
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if err != nil {
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return
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}
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// На данний момен схема - наступна. Всі сторінки - data та index - зафіксовані в кеші.
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// Отже запис на диск пройде максимально швидко. Після цього ReferenceCount кожної
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// сторінки зменшиться на 1. Оскільки на метрику утримується XLock, сторінки мають
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// ReferenceCount = 1 (немає інших читачів).
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waitCh := make(chan struct{})
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task := WriteTask{
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WaitCh: waitCh,
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DataPage: redo.PageToWrite{
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PageNo: newDataPage.PageNo,
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Data: newDataPage.Data,
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},
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IndexPages: redoWriter.IndexPagesToWrite(),
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}
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s.appendWriteTaskToQueue(task)
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<-waitCh
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for _, pageNo := range dataPagesToRelease {
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s.releaseDataPage(pageNo)
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}
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for _, pageNo := range indexPagesToRelease {
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s.releaseIndexPage(pageNo)
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}
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return redoWriter.GetReport(), nil
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}
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// DELETE
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type PageLists struct {
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DataPages []uint32
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IndexPages []uint32
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}
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type Level struct {
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PageNo uint32
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PageData []byte
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Idx int
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ChildQty int
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}
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func (s *Atree) GetAllPages(rootPageNo uint32) (_ PageLists, err error) {
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var (
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dataPages []uint32
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indexPages []uint32
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levels []*Level
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)
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buf, err := s.fetchIndexPage(rootPageNo)
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if err != nil {
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err = fmt.Errorf("fetchIndexPage(%d): %s", rootPageNo, err)
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return
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}
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indexPages = append(indexPages, rootPageNo)
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if buf[isDataPageNumbersIdx] == 1 {
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pageNumbers := listPageNumbers(buf)
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dataPages = append(dataPages, pageNumbers...)
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s.releaseIndexPage(rootPageNo)
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return PageLists{
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DataPages: dataPages,
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IndexPages: indexPages,
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}, nil
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}
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levels = append(levels, &Level{
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PageNo: rootPageNo,
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PageData: buf,
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Idx: 0,
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ChildQty: bin.GetUint16AsInt(buf[indexRecordsQtyIdx:]),
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})
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for {
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if len(levels) == 0 {
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return PageLists{
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DataPages: dataPages,
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IndexPages: indexPages,
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}, nil
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}
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lastIdx := len(levels) - 1
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level := levels[lastIdx]
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if level.Idx < level.ChildQty {
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pageNo := getPageNo(level.PageData, level.Idx)
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level.Idx++
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var buf []byte
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buf, err = s.fetchIndexPage(pageNo)
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if err != nil {
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err = fmt.Errorf("fetchIndexPage(%d): %s", pageNo, err)
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return
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}
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indexPages = append(indexPages, pageNo)
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if buf[isDataPageNumbersIdx] == 1 {
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pageNumbers := listPageNumbers(buf)
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dataPages = append(dataPages, pageNumbers...)
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s.releaseIndexPage(pageNo)
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} else {
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levels = append(levels, &Level{
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PageNo: pageNo,
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PageData: buf,
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Idx: 0,
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ChildQty: bin.GetUint16AsInt(buf[indexRecordsQtyIdx:]),
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})
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}
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} else {
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s.releaseIndexPage(level.PageNo)
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levels = levels[:lastIdx]
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}
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}
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}
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