JPA - Spanning a transaction over multiple JpaRepository method calls - spring-boot

I'm using SpringBoot 2.x with SpringData-JPA accessing the database via a CrudRepository.
Basically, I would like to call the CrudRepository's methods to update or persist the data. In one use case, I would like to delete older entries from the database (for the brevity of this example assume: delete all entries from the table) before I insert a new element.
In case persisting the new element fails for any reason, the delete operation shall be rolled back.
However, the main problem seems to be that new transactions are opened for every method called from the CrudRepository. Even though, a transaction was opened by the method from the calling service. I couldn't get the repository methods to use the existing transaction.
Getting transaction for [org.example.jpatrans.ChairUpdaterService.updateChairs]
Getting transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.deleteWithinGivenTransaction]
Completing transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.deleteWithinGivenTransaction]
I've tried using different Propagation. (REQUIRED, SUPPORTED, MANDATORY) on different methods (service/repository) to no avail.
Changing the methods #Transactional annoation to #Transactional(propagation = Propagation.NESTED) sounded that this would just do that, but didn't help.
JpaDialect does not support savepoints - check your JPA provider's capabilities
Can I achieve the expected behaviour, not using an EntityManager directly?
I also would like to avoid to having to be using native queries as well.
Is there anything I have overlooked?
For demonstration purposes, I've created a very condensed example.
The complete example can be found at https://gitlab.com/cyc1ingsir/stackoverlow_jpa_transactions
Here are the main (even more simplified) details:
First I've got a very simple entity defined:
#Entity
#Table(name = "chair")
#Data
#AllArgsConstructor
#NoArgsConstructor
public class Chair {
// Not auto generating the id is on purpose
// for later testing with non unique keys
#Id
private int id;
#Column(name = "legs", nullable = false)
private Integer legs;
}
The connection to the database is made via the CrudRepository:
#Repository
public interface ChairRepository extends CrudRepository<Chair, Integer> {
}
This is being called from another bean (main methods here are updateChairs and doUpdate):
#Slf4j
#Service
#AllArgsConstructor
#Transactional
public class ChairUpdater {
ChairRepository repository;
/*
* Initialize the data store with some
* sample data
*/
public void initializeChairs() {
repository.deleteAll();
Chair chair4 = new Chair(1, 4);
Chair chair3 = new Chair(2, 3);
repository.save(chair4);
repository.save(chair3);
}
public void addChair(int id, Integer legCount) {
repository.save(new Chair(id, legCount));
}
/*
* Expected behaviour:
* when saving a given chair fails ->
* deleting all other is rolled back
*/
#Transactional
public void updateChairs(int id, Integer legCount) {
Chair chair = new Chair(id, legCount);
repository.deleteAll();
repository.save(chair);
}
}
The goal, I want to achieve is demonstrated by these two test cases:
#Slf4j
#RunWith(SpringRunner.class)
#DataJpaTest
#Import(ChairUpdater.class)
public class ChairUpdaterTest {
private static final int COUNT_AFTER_ROLLBACK = 3;
#Autowired
private ChairUpdater updater;
#Autowired
private ChairRepository repository;
#Before
public void setup() {
updater.initializeChairs();
}
#Test
public void positiveTest() throws UpdatingException {
updater.updateChairs(3, 10);
}
#Test
public void testRollingBack() {
// Trying to update with an invalid element
// to force rollback
try {
updater.updateChairs(3, null);
} catch (Exception e) {
LOGGER.info("Rolled back?", e);
}
// Adding a valid element after the rollback
// should succeed
updater.addChair(4, 10);
assertEquals(COUNT_AFTER_ROLLBACK, repository.findAll().spliterator().getExactSizeIfKnown());
}
}
Update:
It seems to work, if the repository is not extended from either CrudRepository or JpaRepository but from a plain Repository, definening all needed methods explicitly. For me, that seems to be a workaround rather than beeing a propper solution.
The question it boils down to seems to be: Is it possible to prevent SimpleJpaRepository from opening new transactions for every (predefined) method used from the repository interface? Or, if that is not possible, how to "force" the transaction manager to reuse the transaction, opened in the service to make a complete rollback possible?

Hi I found this documentation that looks will help you:
https://www.logicbig.com/tutorials/spring-framework/spring-data/transactions.html
Next an example take from the previous web site:
#Configuration
**#ComponentScan
#EnableTransactionManagement**
public class AppConfig {
....
}
Then we can use transactions like this:
#Service
public class MyExampleBean{
**#Transactional**
public void saveChanges() {
**repo.save(..);
repo.deleteById(..);**
.....
}
}

Yes this is possible. First alter the #Transactional annotation so that it includes rollBackFor = Exception.class.
/*
* Expected behaviour:
* when saving a given chair fails ->
* deleting all other is rolled back
*/
#Transactional(rollbackFor = Exception.class)
public void updateChairs(int id, Integer legCount) {
Chair chair = new Chair(id, legCount);
repository.deleteAll();
repository.save(chair);
}
This will cause the transaction to roll back for any exception and not just RuntimeException or Error.
Next you must add enableDefaultTransactions = false to #EnableJpaRepositories and put the annotation on one of your configuration classes if you hadn't already done so.
#Configuration
#EnableJpaRepositories(enableDefaultTransactions = false)
public class MyConfig{
}
This will cause all inherited jpa methods to stop creating a transaction by default whenever they're called. If you want custom jpa methods that you've defined yourself to also use the transaction of the calling service method, then you must make sure that you didn't annotate any of these custom methods with #Transactional. Because that would prompt them to start their own transactions as well.
Once you've done this all of the repository methods should be executed using the service method transaction only. You can test this by creating and using a custom update method that is annotated with #Modifying. For more on testing please see my answer in this SO thread. Spring opens a new transaction for each JpaRepository method that is called within an #Transactional annotated method

Related

Without JPA #Transaction and save() when is the commit done?

When a method has a #Transaction annatotion, I know the commit is done at the end of the method. But when I don't use #Transaction, it's not clear to me when the commit is done. In my example I don't use #Transaction, do the real change in another service and don't use someRepository .save(), but it still works:
#Service
public class ServiceA {
private final SomeRepository someRepository;
private final ServiceB serviceB;
public ServiceA(SomeRepository someRepository, ) {
this.someRepository = someRepository;
this.serviceB = serviceB;
}
// Called from controller
public void doStuff() {
var someEntity = someRepository.findById(1);
serviceB.makeChange(someEntity);
}
}
#Service
public class ServiceB {
public ServiceB() {}
public void makeChange(SomeEntity someEntity) {
someEntity.setName("Test"); // this is working and committed to the database
}
}
So actually I have 2 questions:
When I don't add a #Transaction annatotion to a method when is the commit done?
I don't even have to call someRepository.save(entity)? I thought that worked only when using the #Transaction annotation?
Context:
Spring Boot 2.2.6
"spring-boot-starter-data-jpa" as dependency
first one clarification: the #Transactional annotation does not mean there is a commit at end of the method. It means the method joins the transaction (or start a new one - this depends on the propagation attributes to be precise), so the commit (or rollback) will be performed at the end of the transaction, which can (and often does) involve multiple methods with various DB access.
Normally Spring (or another transaction manager) takes care of this (ie disabling auto-commit).
#Transactional missing
There is no transactional context so the commit is performed immediately as the database in modified. There is no rollback option and, if there is an error, the data integrity might be violated,
#Transactional defined
During the transactions the JPA entities are in managed-state, at the end of the transaction the state is automatically flushed to the DB (no need to call someRepository.save(entity)

Spring boot #Transactional doesn't rollback

I am using Spring boot application, on that i am trying to achieve Transactional management. But Spring doesn't rollback the data which saved in same method.
Code base: https://github.com/vinothr/spring-boot-transactional-example
Can any one help me?
This is my repository class for 'Test' entity.
#Repository
public interface TestRepository extends CrudRepository<com.example.demo.Test, Long> {
}
I have created one end-point which used to save the data to 'Test' entity. After save happen, I thrown RunTimeException, but it is not rollbacking the saved value
#GetMapping("/test")
#Transactional
public void create() {
System.out.println("test");
final Test p = createTest();
testRepository.save(p);
final Test p1 = createTest();
testRepository.save(p1);
throw new RuntimeException();
}
It works fine after I changed into 'InnoDB' engine because I was using 'MyISAM' engine which doesn't support transaction.
ALTER TABLE my_table ENGINE = InnoDB;
Try indicate #Transactional(rollbackFor = RuntimeException.class)

Making a method transactional in Spring

I use a hibernate as JPA provider
#RestController
public class RestController {
private final TestService testService;
#PostMapping(value = "/file/{entityId}", produces = MediaType.APPLICATION_OCTET_STREAM_VALUE)
public void test(#PathVariable #NotNull UUID entityId) {
testService.delete(entityId);
}
}
class TestService {
#AutoWired
EntityRepository repo; // <- Crud repository from Spring Data
public void delete(UUID id2){
//if row not exists with id == id2
throw NoFoundException
// else
//remove from database using repo.
}
}
And how to resolve the following case:
"if row not exists with id == id2 " evaluated to false, because object exists in fact.
Other thread deleted that row.
"remove from database using repo" <- error, there is no such row because it was removed by other thread in the step 2.
You can use #Transactional on your Service methods to ensure your database operations run in a transaction. By default, you can roll back the transaction if you throw a unchecked exception inside the annotated method. You can also specify on which exceptions to rollback using #Transactional's rollbackFor Parameter
Not sure why you've got a delete method that is basically doing exactly the same as the SimpleJpaRepository delete method, so for starters I'd change your code to
repo.delete(entityId)
and get rid of test service.
If you are worried about getting a EmptyResultDataAccessException when there is no data to delete, either catch the exception and ignore it or use pessimistic locking on whatever else is doing deletes, as explained
here
You can use the annotation #Transaction for your service method delete(UUID id2).Default propagation of #Transaction is Propagation.REQUIRED which means that if you get an existing transaction it continues that and if you do not have existing transaction it will create one for you.

Why does OpenEntityManagerInViewFilter change #Transactional propagation REQUIRES_NEW behavior?

Using Spring 4.3.12, Spring Data JPA 1.11.8 and Hibernate 5.2.12.
We use the OpenEntityManagerInViewFilter to ensure our entity relationships do not throw LazyInitializationException after an entity has been loaded. Often in our controllers we use a #ModelAttribute annotated method to load an entity by id and make that loaded entity available to a controller's request mapping handler method.
In some cases like auditing we have entity modifications that we want to commit even when some other transaction may error and rollback. Therefore we annotate our audit work with #Transactional(propagation = Propagation.REQUIRES_NEW) to ensure this transaction will commit successfully regardless of any other (if any) transactions which may or may not complete successfully.
What I've seen in practice using the OpenEntityManagerInviewFilter, is that when Propagation.REQUIRES_NEW transactions attempt to commit changes which occurred outside the scope of the new transaction causing work which should always result in successful commits to the database to instead rollback.
Example
Given this Spring Data JPA powered repository (the EmployeeRepository is similarly defined):
import org.springframework.data.jpa.repository.JpaRepository;
public interface MethodAuditRepository extends JpaRepository<MethodAudit,Long> {
}
This service:
#Service
public class MethodAuditorImpl implements MethodAuditor {
private final MethodAuditRepository methodAuditRepository;
public MethodAuditorImpl(MethodAuditRepository methodAuditRepository) {
this.methodAuditRepository = methodAuditRepository;
}
#Override #Transactional(propagation = Propagation.REQUIRES_NEW)
public void auditMethod(String methodName) {
MethodAudit audit = new MethodAudit();
audit.setMethodName(methodName);
audit.setInvocationTime(LocalDateTime.now());
methodAuditRepository.save(audit);
}
}
And this controller:
#Controller
public class StackOverflowQuestionController {
private final EmployeeRepository employeeRepository;
private final MethodAuditor methodAuditor;
public StackOverflowQuestionController(EmployeeRepository employeeRepository, MethodAuditor methodAuditor) {
this.employeeRepository = employeeRepository;
this.methodAuditor = methodAuditor;
}
#ModelAttribute
public Employee loadEmployee(#RequestParam Long id) {
return employeeRepository.findOne(id);
}
#GetMapping("/updateEmployee")
// #Transactional // <-- When uncommented, transactions work as expected (using OpenEntityManagerInViewFilter or not)
public String updateEmployee(#ModelAttribute Employee employee, RedirectAttributes ra) {
// method auditor performs work in new transaction
methodAuditor.auditMethod("updateEmployee"); // <-- at close of this method, employee update occurrs trigging rollback
// No code after this point executes
System.out.println(employee.getPin());
employeeRepository.save(employee);
return "redirect:/";
}
}
When the updateEmployee method is exercised with an invalid pin number updateEmployee?id=1&pin=12345 (pin number is limited in the database to 4 characters), then no audit is inserted into the database.
Why is this? Shouldn't the current transaction be suspended when the MethodAuditor is invoked? Why is the modified employee flushing when this Propagation.REQUIRES_NEW transaction commits?
If I wrap the updateEmployee method in a transaction by annotating it as #Transactional, however, audits will persist as desired. And this will work as expected whether or not the OpenEntityManagerInViewFilter is used.
While your application (server) tries to make two separate transactions you are still using a single EntityManager and single Datasource so at any given time JPA and the database see just one transaction. So if you want those things to be separated you need to setup two Datasources and two EntityManagers

JPA: Nested transactional method is not rolled back

UPD 1: Upon further research I think the following information may be useful:
I obtain datasource through JNDI lookup on WildFly 9.0.2, then 'wrap' it into in instance of HikariDataSource (e. g. return new HikariDataSource(jndiDSLookup(dsName))).
the transaction manager that ends up being used is JTATransactionManager.
I do not configure the transaction manager in any way.
ORIGINAL QUESTION:
I am experiencing an issue with JPA/Hibernate and (maybe) Spring-Boot where DB changes introduced in a transactional method of one class called from a transactional method of another class are committed even though the changes in the caller method are rolled back (as they should be).
Here are my transactional services
StuffService:
#Service
#Transactional(rollbackFor = IOException.class)
public class StuffService {
#Inject private BarService barService;
#Inject private StuffRepository stuffRepository;
public Stuff updateStuff(Stuff stuff) {
try {
if (null != barService.doBar(stuff)) {
stuff.setSomething(SOMETHING);
stuff.setSomethingElse(SOMETHING_ELSE);
return stuffRepository.save(stuff);
}
} catch (FirstCustomException e) {
logger.error("Blah", e);
throw new SecondCustomException(e.getMessage());
}
throw new SecondCustomException("Blah 2");
}
// other methods
}
and BarService:
#Service
#Transactional
public class BarService {
#Inject private EntityARepository entityARepository;
#Inject private EntityBRepository entityBRepository;
/*
* updates existing entity A and persists new entity B.
*/
public EntityA doBar(Stuff stuff) throws FirstCustomException {
EntityA a = entityARepository.findOne(/* some criteria */);
a.setSomething(SOMETHING);
EntityB b = new EntityB();
b.setSomething(SOMETHING);
b.setSomethingElse(SOMETHING_ELSE);
entityBRepository.save(b);
return entityARepository.save(a);
}
// other methods
}
EntityARepository and EntityBRepository are very similar Spring-Boot repositories defined like this:
public interface EntityARepository extends JpaRepository<EntityA, Long>{
EntityA findOne(/* some criteria */);
}
FirstCustomException extends Throwable
SecondCustomException extends RuntimeException
Stuff entity is versioned, and every once in a while it is concurrently updated by StuffService.updateStuff(). In that case changes to one of the stuff instances are rolled back, as expected, but everything that happens in the barService.doBar() ends up being committed.
This puzzles me quite a lot since transaction propagation on both methods should be REQUIRED (the default one) and both methods belong to different classes, hence #Transactional should apply for both.
I did see Transaction is not completely rolled back after server throws OptimisticLockException1
But it did not really answer my question.
Can anyone please give me an idea of what's going on?
Thank you.
This isn't a 'nested' transaction - these services are operating in completely independent transactions. If you want the rollback of one to affect the other, you need to have them take part in the same transaction rather than start its own.
Or if your issue is that there is a problem with the version of 'stuff' passed into the doBar method and you want it verified, you will need to do something with the stuff instance that would cause an optimistic lock check, and so result in an exception if it is stale. see EntityManager.lock

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