Try To Use `savepoint` In Spring JPA/Hibernate

savepoint

This article describes my failed attempt to use the PostgreSQL SAVEPOINT in Spring JPA.
About PostgreSQL SAVEPOINT.

EntityManager

@PersistenceContext  
private EntityManager entityManager;

@Transactional(propagation=NESTED, isolation= READ_UNCOMMITTED)  
public void transferWithSavePoint(String fromAccount, String toAccount, String anotherAccount,  
                                  double amount) throws SQLException {  
    // step 1  
    Account from = accountRepository.findByName(fromAccount);  
    Branch fromBranch = branchRepository.findByName(from.getBranchName());  
  
    from.setBalance(from.getBalance().subtract(BigDecimal.valueOf(amount)));  
    fromBranch.setBalance(fromBranch.getBalance().subtract(BigDecimal.valueOf(amount)));  
  
    accountRepository.save(from);  
    branchRepository.save(fromBranch);  
  
    Connection connection = entityManager.unwrap(SessionImpl.class).connection();  
    Savepoint savepoint = connection.setSavepoint();  
  
    // step 2  
    Account to = accountRepository.findByName(toAccount);  
    Branch toBranch = branchRepository.findByName(to.getBranchName());  
  
    to.setBalance(to.getBalance().add(BigDecimal.valueOf(amount)));  
    toBranch.setBalance(toBranch.getBalance().add(BigDecimal.valueOf(amount)));  
  
    accountRepository.save(to);  
    branchRepository.save(toBranch);  
  
    connection.rollback(savepoint);  
  
    // final step  
    Account finalAccount = accountRepository.findByName(anotherAccount);  
    Branch finalBranch = branchRepository.findByName(to.getBranchName());  
  
    finalAccount.setBalance(finalAccount.getBalance().add(BigDecimal.valueOf(amount)));  
    finalBranch.setBalance(finalBranch.getBalance().add(BigDecimal.valueOf(amount)));  
  
    accountRepository.save(finalAccount);  
    branchRepository.save(finalBranch);  
}

I use Connection Pool in this project, so the connection created by EntityManager is different @Transactional method’s connection

• savepoint: is before transferWithSavePoint
• rollback: rollback to all of the operations before, so `STEP1` is rollback, but `STEP2` and `Final STEP` is done.

Next Try: AbstractTransactionStatus

@Autowired  
private JdbcTemplate jdbcTemplate;  
  
@Autowired  
private TransactionTemplate transactionTemplate;

public void transferWithSavePoint(String fromAccount, String toAccount, String anotherAccount,  
                                  double amount) {  
    transactionTemplate.execute(status -> {  
        Account from = accountRepository.findByName(fromAccount);  
        Branch fromBranch = branchRepository.findByName(from.getBranchName());  
  
        from.setBalance(from.getBalance().subtract(BigDecimal.valueOf(amount)));  
        fromBranch.setBalance(fromBranch.getBalance().subtract(BigDecimal.valueOf(amount)));  
  
        accountRepository.save(from);  
        branchRepository.save(fromBranch);  
  
        Object savepoint = status.createSavepoint();  
  
        // step 2  
        Account to = accountRepository.findByName(toAccount);  
        Branch toBranch = branchRepository.findByName(to.getBranchName());  
  
        to.setBalance(to.getBalance().add(BigDecimal.valueOf(amount)));  
        toBranch.setBalance(toBranch.getBalance().add(BigDecimal.valueOf(amount)));  
  
        accountRepository.save(to);  
        branchRepository.save(toBranch);  
  
        status.rollbackToSavepoint(savepoint);  
  
        // final step  
        Account finalAccount = accountRepository.findByName(anotherAccount);  
        Branch finalBranch = branchRepository.findByName(to.getBranchName());  
  
        finalAccount.setBalance(finalAccount.getBalance().add(BigDecimal.valueOf(amount)));  
        finalBranch.setBalance(finalBranch.getBalance().add(BigDecimal.valueOf(amount)));  
  
        accountRepository.save(finalAccount);  
        branchRepository.save(finalBranch);  
  
        status.releaseSavepoint(savepoint);  
  
        return null;    });  
}

Also failed:

JpaDialect does not support savepoints — check your JPA provider’s capabilities

Then I start to search ‘How to use savepoint in Hibernate’ online:

Please note that this is not a recommended way to use Spring JPA. It’s better to structure your transactions in such a way that you don’t need to use savepoints or nested transactions. If you find yourself needing them, it might be a sign that your transactions are too complex and should be broken down into smaller parts.

Maybe I’m wrong from the beginning, indeed, I won’t encounter it in real application scenarios, but I’m just trying to figure out how to implement it, so let me know if you have any good ideas.