func mustGetUUIDBytes() []byte {
	u, err := uuid.NewRandom()
	if err != nil {
		logger.CriticalIf(GlobalContext, err)
	}
	return u[:]
}

// Create an s3 compatible MD5sum for complete multipart transaction.
func getCompleteMultipartMD5(parts []CompletePart) string {
	var finalMD5Bytes []byte
	for _, part := range parts {
		md5Bytes, err := hex.DecodeString(canonicalizeETag(part.ETag))
		if err != nil {

	defer conn.Close()
	tx.Statement.ConnPool = conn
	return fc(tx)
}

// Transaction start a transaction as a block, return error will rollback, otherwise to commit. Transaction executes an
// arbitrary number of commands in fc within a transaction. On success the changes are committed; if an error occurs
// they are rolled back.
func (db *DB) Transaction(fc func(tx *DB) error, opts ...*sql.TxOptions) (err error) {
	panicked := true

		tx3 := DB.Session(&gorm.Session{PrepareStmt: true})
		if err := tx3.Transaction(func(tx4 *gorm.DB) error {
			// nested transaction
			return tx4.Transaction(func(tx5 *gorm.DB) error {
				return tx5.First(&User{}, "name = ?", "transaction-2").Error
			})
		}); err != nil {
			t.Fatalf("prepare statement and nested transcation coexist" + err.Error())
		}
	})
}

func TestCancelTransaction(t *testing.T) {
	ctx := context.Background()

)

// for Config.cacheStore store PreparedStmtDB key
const preparedStmtDBKey = "preparedStmt"

// Config GORM config
type Config struct {
	// GORM perform single create, update, delete operations in transactions by default to ensure database data integrity
	// You can disable it by setting `SkipDefaultTransaction` to true
	SkipDefaultTransaction bool
	// NamingStrategy tables, columns naming strategy
	NamingStrategy schema.Namer

	}

	return evalDisks(disks, errs), err
}

// PutObjectPart - reads incoming stream and internally erasure codes
// them. This call is similar to single put operation but it is part
// of the multipart transaction.
//
// Implements S3 compatible Upload Part API.
func (er erasureObjects) PutObjectPart(ctx context.Context, bucket, object, uploadID string, partID int, r *PutObjReader, opts ObjectOptions) (pi PartInfo, err error) {

	DB.Migrator().DropTable(&Token{}, &TokenOwner{})
	DB.AutoMigrate(&Token{}, &TokenOwner{})

	saveTokenOwner := func(owner *TokenOwner) (*TokenOwner, error) {
		var newOwner TokenOwner
		if err := DB.Transaction(func(tx *gorm.DB) error {
			if err := tx.Session(&gorm.Session{FullSaveAssociations: true}).Save(owner).Error; err != nil {
				return err
			}

	set := s.getHashedSet(object)
	return set.AbortMultipartUpload(ctx, bucket, object, uploadID, opts)
}

// CompleteMultipartUpload - completes a pending multipart transaction, on hashedSet based on object name.
func (s *erasureSets) CompleteMultipartUpload(ctx context.Context, bucket, object, uploadID string, uploadedParts []CompletePart, opts ObjectOptions) (objInfo ObjectInfo, err error) {