Function NewDB

engine/db.go:59–101

NewDB open a new db instance

(options config.Options)

// NewDB open a new db instance
func NewDB(options config.Options) (*DB, error) {
	zap.L().Info("open db", zap.Any("options", options))
	// check options first
	if err := checkOptions(options); err != nil {
		return nil, err
	}

	// check data dir, if not exist, create it
	if _, err := os.Stat(options.DirPath); os.IsNotExist(err) {
		if err := os.MkdirAll(options.DirPath, os.ModePerm); err != nil {
			return nil, err
		}
	}

	// init db instance
	db := &DB{
		options:    options,
		lock:       new(sync.RWMutex),
		olderFiles: make(map[uint32]*data2.DataFile),
		index:      index.NewIndexer(options.IndexType, options.DirPath),
	}

	// load merge files
	if err := db.loadMergeFiles(); err != nil {
		return nil, err
	}

	// load data files
	if err := db.loadDataFiles(); err != nil {
		return nil, err
	}

	// load index from hint file
	if err := db.loadIndexFromHintFile(); err != nil {
		return nil, err
	}

	// load index from data files
	if err := db.loadIndexFromDataFiles(); err != nil {
		return nil, err
	}
	return db, nil
}

func checkOptions(options config.Options) error {
	if options.DirPath == "" {