Method getValueByPosition

engine/db.go:321–345

getValueByPosition Get the corresponding value based on the location index information

(logRecordPst *data2.LogRecordPst)

// getValueByPosition Get the corresponding value based on the location index information
func (db *DB) getValueByPosition(logRecordPst *data2.LogRecordPst) ([]byte, error) {
	// Find the corresponding data file according to the file id
	var dataFile *data2.DataFile
	if logRecordPst.Fid == db.activeFile.FileID {
		dataFile = db.activeFile
	} else {
		dataFile = db.olderFiles[logRecordPst.Fid]
	}

	// The data file is empty
	if dataFile == nil {
		return nil, _const.ErrDataFailNotFound
	}

	// The corresponding data is read according to the offset
	logRecord, _, err := dataFile.ReadLogRecord(logRecordPst.Offset)
	if err != nil {
		return nil, nil
	}
	if logRecord.Type == data2.LogRecordDeleted {
		return nil, _const.ErrKeyNotFound
	}

	return logRecord.Value, nil
}

// Delete data according to the key
func (db *DB) Delete(key []byte) error {