wp

recovery/recovery.go

@@ -0,0 +1,221 @@
+package recovery
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"gordenko.dev/dima/qb"
+	"gordenko.dev/dima/qb/freelist"
+	"gordenko.dev/dima/qb/storage"
+)
+
+// Result зберігає результати для обох типів файлів
+type FileVersion struct {
+	Name    string
+	Version int
+}
+
+// FindMaxSnapshotFiles шукає файли з розширеннями .snapshot_XXX та .wal_XXX
+// і повертає структуру з максимальними номерами.
+func findFileLatestVersion(dir string, extPrefix string) (FileVersion, error) {
+	var x FileVersion
+	if !strings.HasPrefix(extPrefix, ".") {
+		extPrefix = "." + extPrefix
+	}
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		return x, err
+	}
+	for _, entry := range entries {
+		if entry.IsDir() {
+			continue
+		}
+		name := entry.Name()
+		ext := filepath.Ext(name)
+
+		if strings.HasPrefix(ext, extPrefix) {
+			version, err := strconv.Atoi(strings.TrimPrefix(ext, extPrefix))
+			if err == nil {
+				if version > x.Version || x.Name == "" {
+					x.Name = name
+					x.Version = version
+				}
+			}
+		}
+	}
+	return x, nil
+}
+
+var (
+	ErrLostSnapshot = errors.New("lost snapshot")
+)
+
+type RecoveryFiles struct {
+	Snapshot       string
+	WAL            string
+	SnapshotNumber int
+}
+
+func resolveRecoveryFiles(dir string) (_ RecoveryFiles, err error) {
+	wal, err := findFileLatestVersion(dir, "wal_")
+	if err != nil {
+		return
+	}
+	snapshot, err := findFileLatestVersion(dir, "snapshot_")
+	if err != nil {
+		return
+	}
+	if snapshot.Name != "" {
+		if wal.Name != "" {
+			if snapshot.Version == wal.Version {
+				return RecoveryFiles{
+					Snapshot:       snapshot.Name,
+					WAL:            wal.Name,
+					SnapshotNumber: snapshot.Version,
+				}, nil
+			} else if snapshot.Version > wal.Version {
+				return RecoveryFiles{
+					Snapshot:       snapshot.Name,
+					SnapshotNumber: snapshot.Version,
+				}, nil
+			} else {
+				// WAL version > snapshot version
+				err = ErrLostSnapshot
+				return
+			}
+		} else {
+			return RecoveryFiles{
+				Snapshot:       snapshot.Name,
+				SnapshotNumber: snapshot.Version,
+			}, nil
+		}
+	} else {
+		if wal.Name != "" {
+			if wal.Version == 0 {
+				return RecoveryFiles{
+					WAL: wal.Name,
+				}, nil
+			} else {
+				err = ErrLostSnapshot
+				return
+			}
+		} else {
+			// no files - ok, 1st start of database
+			return
+		}
+	}
+}
+
+type RecoveryReport struct {
+	//Metrics []
+	SnapshotNumber int
+	WAL            string
+	IndexFreeList  *freelist.FreeList
+	DataFreeList   *freelist.FreeList
+}
+
+func Recovery(dir string, databaseName string) (_ RecoveryReport, err error) {
+	files, err := resolveRecoveryFiles(dir)
+	if err != nil {
+		return
+	}
+	var (
+		freeIndexPages []uint32
+		freeDataPages  []uint32
+	)
+	if files.Snapshot != "" {
+		var out storage.ReadSnapshotOut
+		out, err = storage.ReadSnapshot(files.Snapshot)
+		if err != nil {
+			return
+		}
+		//
+		freeIndexPages = out.IndexPageNumbers
+		freeDataPages = out.DataPageNumbers
+	}
+
+	if files.WAL != "" {
+		var (
+			walReader   *storage.WALReader
+			walReplayer *storage.WALReplayer
+		)
+		walReader, err = storage.NewWALReader(storage.WALReaderOptions{
+			//FileName:   JoinWALFileName(s.dir, files.WAL),
+			BufferSize: 8 * 1024 * 1024,
+		})
+		if err != nil {
+			return
+		}
+
+		walReplayer, err = storage.NewWALReplayer(storage.WALReplayerOptions{
+			WALReader:      walReader,
+			Metrics:        snapshot.Metrics,
+			FreeIndexPages: freeIndexPages,
+			FreeDataPages:  freeDataPages,
+		})
+		if err != nil {
+			return
+		}
+
+		err = walReplayer.Replay()
+		if err != nil {
+			return
+		}
+		// перезаписую сторінки із останнього комміта
+		var dataFile *os.File
+		dataFile, err = os.OpenFile(qb.GetDataFilePath(dir, databaseName), os.O_WRONLY, 0666)
+		if err != nil {
+			return
+		}
+		err = storage.WriteDataPages(dataFile, walReplayer.DataPages())
+		if err != nil {
+			return
+		}
+		err = dataFile.Close()
+		if err != nil {
+			return
+		}
+		var indexFile *os.File
+		indexFile, err = os.OpenFile(qb.GetIndexFilePath(dir, databaseName), os.O_WRONLY, 0666)
+		if err != nil {
+			return
+		}
+		err = storage.WriteIndexPages(indexFile, walReplayer.IndexPages())
+		if err != nil {
+			return
+		}
+		err = indexFile.Close()
+		if err != nil {
+			return
+		}
+	}
+
+	indexFreeList, err := freelist.New(freelist.Options{
+		PageSize:      2048,
+		BaseFilePath:  filepath.Join(dir, databaseName+".free_index"),
+		DeltaFilePath: filepath.Join(dir, databaseName+".free_index_delta"),
+	})
+
+	// FIX free pages sync
+	dataFreeList, err := freelist.New(freelist.Options{
+		PageSize:      2048,
+		BaseFilePath:  filepath.Join(dir, databaseName+".free_data"),
+		DeltaFilePath: filepath.Join(dir, databaseName+".free_data_delta"),
+	})
+
+	return RecoveryReport{
+		SnapshotNumber: files.SnapshotNumber,
+		WAL:            files.WAL,
+		IndexFreeList:  indexFreeList,
+		DataFreeList:   dataFreeList,
+	}, nil
+}
+
+//func (s *Database) relayMetricsToMetrics(replayMetrics map[uint32]*ReplayMetric) {
+//for metricID, x := range replayMetrics {
+//s.metrics[metricID] = x.ToMetric() FIX
+//}
+//}