Spring opens a new transaction for each JpaRepository method that is called within an @Transactional-CodePudding

I have a method that is annotated with @Transactional. That should mean that any database queries that are fired within this method should all use the same transaction. But in reality that doesn't happen. What does happen is that a transaction is opened for the method itself but then when the first JpaRepository method is called a new transaction is opened for that particular method call.

To make matters more complex, For custom repository methods this new transaction is only opened when the JpaRepository or the JpaRepository custom method is annotated with @Transactional as well. If not i get the following trace log statement about it:

No need to create transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findFirstByIdNotNull]: This method is not transactional.

So it doesn't create a new transaction but it also doesn't seem to use the transaction created by the calling method either.

Heres the repository class:

@Repository
public interface LanguageDao extends JpaRepository<Language, Long> {

@Transactional
public Language findByLanguageCode(String languageCode);

public Language findByIdNotNull();

}

Heres the method that uses different repository methods.

@Transactional
public void afterSingletonsInstantiated() {
    languageDao.findByLanguageCode(); //This custom method opens a new transaction, but only because i've annotated this method with @Transactional as well.
    languageDao.findAll(); //This one as well because its a standard JpaRepository method.
    languageDao.findByIdNotNull();//This custom method doesn't because it lacks its own @Transactional annotation.
}

Heres the @Configuration file, with transaction management and jpa repositories enabled

@EnableJpaRepositories(basePackages={"DAOs"}, transactionManagerRef = "customTransactionManager", enableDefaultTransactions = true)
@EnableTransactionManagement
@Configuration
public class RootConfig implements InitializingBean {

    @Bean(name = "customTransactionManager")
    JpaTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory);
        if (shouldCreateInitialLuceneIndex) { 
            EntityManager entityManager = entityManagerFactory.createEntityManager();
            createInitialLuceneIndex(entityManager);
            entityManager.close();
        }
        return transactionManager;
    }
}

Relevant application.properties settings

spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.database-platform = org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.open-in-view = false

A bit of actual logs. The first line shows that a transaction for the method afterSingletonsInstantiated is created.

[TRACE] 2021-11-08 15:32:40.811 [main] TransactionInterceptor - Getting transaction for [config.StartupChecks$$EnhancerBySpringCGLIB$$134b7631.afterSingletonsInstantiated]
[INFO ] 2021-11-08 15:32:40.815 [main] StartupChecks - Calling sequence table reset procedure
[DEBUG] 2021-11-08 15:32:40.833 [main] SQL - {call RESET_SEQUENCE_TABLE_VALUES_TO_LATEST_ID_VALUES()}
[INFO ] 2021-11-08 15:32:41.087 [main] StartupChecks - Sequence tables reset call finished!
[INFO ] 2021-11-08 15:32:41.087 [main] StartupChecks - doing stuff
[INFO ] 2021-11-08 15:32:41.087 [main] StartupChecks - testing!
[TRACE] 2021-11-08 15:32:41.087 [main] TransactionInterceptor - Getting transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findAll]
[DEBUG] 2021-11-08 15:32:41.088 [main] SQL - select language0_.id as id1_77_, language0_.dateCreated as datecrea2_77_, language0_.englishLanguageName as englishl3_77_, language0_.languageCode as language4_77_, language0_.rightToLeft as righttol5_77_, language0_.translatedLanguageName as translat6_77_ from languages language0_
[TRACE] 2021-11-08 15:32:41.091 [main] TransactionInterceptor - Completing transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findAll]
[INFO ] 2021-11-08 15:32:41.091 [main] StartupChecks - end test!
[TRACE] 2021-11-08 15:32:41.091 [main] TransactionInterceptor - Getting transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findByLanguageCode]
[DEBUG] 2021-11-08 15:32:41.112 [main] SQL - select language0_.id as id1_77_, language0_.dateCreated as datecrea2_77_, language0_.englishLanguageName as englishl3_77_, language0_.languageCode as language4_77_, language0_.rightToLeft as righttol5_77_, language0_.translatedLanguageName as translat6_77_ from languages language0_ where language0_.languageCode=?
[TRACE] 2021-11-08 15:32:41.113 [main] TransactionInterceptor - Completing transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findByLanguageCode]
[TRACE] 2021-11-08 15:32:41.113 [main] TransactionInterceptor - No need to create transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findFirstByIdNotNull]: This method is not transactional.
[DEBUG] 2021-11-08 15:32:41.115 [main] SQL - select authority0_.ID as id1_7_, authority0_.dateCreated as datecrea2_7_, authority0_.NAME as name3_7_ from AUTHORITY authority0_ where authority0_.ID is not null limit ?
[TRACE] 2021-11-08 15:32:41.120 [main] TransactionInterceptor - No need to create transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findFirstByIdNotNull]: This method is not transactional.

Here is a list of the things that i've already tried.

Annotate languageDao with @Transactional(propagation = Propagation.SUPPORTS) or @Transactional(propagation = Propagation.NESTED). NESTED isn't supported by hibernate and thus this causes an error, This error remains even when i set nestedTransactionAllowed to true on the transactionmanager. The setting SUPPORTS is ignored. The repository still starts a new transaction for each method that is called. (Update: Propagation.MANDATORY has no effect either)
I've named my transactionmanager customTransactionManager and added this as a parameter to @EnableJpaRepositories like so: @EnableJpaRepositories(basePackages={"DAOs"}, transactionManagerRef = "customTransactionManager")
I've set enableDefaultTransactions of @EnableJpaRepositories to false. This causes default methods like findAll() and save() to no longer be executed in a transaction by default. However it doesn't force them to use the transaction of the calling method that was annotated with @Transactional.

So my question is: How do i make the (custom) jpa repositories use the transaction that was started by the calling method?

EDIT: Here JPA - Spanning a transaction over multiple JpaRepository method calls a similar problem is described. According to the user spring only uses the existing transaction when the repository implements Repository instead of CrudRepository or JpaRepository. But this is a workaround.

EDIT 2: My @Transactional annotations keep working when i remove @EnableTransactionManagement. According to this post that can occur when i use spring-boot-starter-jdbc or spring-boot-starter-data-jpa as a dependency, which i do. Could these dependencies somehow interfere with the normal working of the transaction manager?

CodePudding user response：

Here is my attempt at understanding your problem. I would recommend enabling extra debug

logging.level.org.springframework.orm.jpa.JpaTransactionManager=DEBUG

My test Service class - note that this is marked as transactional - for now that's the only place it is put as that's what we intend - to create a transactional boundary.

@Service
public class LanguageService {

    @Autowired
    private LanguageRepository languageRepository;

    @Transactional
    public void runAllMethods() {
        languageRepository.findByLanguageCode("en");
        languageRepository.findAll();
        languageRepository.findByIdNotNull();
    }

}

Next is the repository - there are no transactional annotations.

public interface LanguageRepository extends JpaRepository<Language, Long> {

    public Language findByLanguageCode(String languageCode);

    public Language findByIdNotNull();

}

Now on hitting the service via a controller - I get below logs. Notice the line where it says "Creating new transaction with name [com.shailendra.transaction_demo.service.LanguageService.runAllMethods]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT" - meaning that the transaction was created at the beginning of method invocation.

Also note the statement "Participating in existing transaction" which indicates that method is participating in transaction.

2021-11-09 11:43:06.061 DEBUG 24956 --- [nio-8181-exec-1] o.s.orm.jpa.JpaTransactionManager        : Found thread-bound EntityManager [SessionImpl(2084817241<open>)] for JPA transaction
2021-11-09 11:43:06.061 DEBUG 24956 --- [nio-8181-exec-1] o.s.orm.jpa.JpaTransactionManager        : Creating new transaction with name [com.shailendra.transaction_demo.service.LanguageService.runAllMethods]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
2021-11-09 11:43:06.069 DEBUG 24956 --- [nio-8181-exec-1] o.s.orm.jpa.JpaTransactionManager        : Exposing JPA transaction as JDBC [org.springframework.orm.jpa.vendor.HibernateJpaDialect$HibernateConnectionHandle@3107a702]
2021-11-09 11:43:06.069 TRACE 24956 --- [nio-8181-exec-1] o.s.t.i.TransactionInterceptor           : Getting transaction for [com.shailendra.transaction_demo.service.LanguageService.runAllMethods]
2021-11-09 11:43:06.099 TRACE 24956 --- [nio-8181-exec-1] o.s.t.i.TransactionInterceptor           : No need to create transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findByLanguageCode]: This method is not transactional.
Hibernate: select language0_.id as id1_0_, language0_.date_created as date_cre2_0_, language0_.english_language_name as english_3_0_, language0_.language_code as language4_0_, language0_.right_to_left as right_to5_0_, language0_.translated_language_name as translat6_0_ from language language0_ where language0_.language_code=?
2021-11-09 11:43:06.333 DEBUG 24956 --- [nio-8181-exec-1] o.s.orm.jpa.JpaTransactionManager        : Found thread-bound EntityManager [SessionImpl(2084817241<open>)] for JPA transaction
2021-11-09 11:43:06.333 DEBUG 24956 --- [nio-8181-exec-1] o.s.orm.jpa.JpaTransactionManager        : Participating in existing transaction
2021-11-09 11:43:06.333 TRACE 24956 --- [nio-8181-exec-1] o.s.t.i.TransactionInterceptor           : Getting transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findAll]
Hibernate: select language0_.id as id1_0_, language0_.date_created as date_cre2_0_, language0_.english_language_name as english_3_0_, language0_.language_code as language4_0_, language0_.right_to_left as right_to5_0_, language0_.translated_language_name as translat6_0_ from language language0_
2021-11-09 11:43:06.348 TRACE 24956 --- [nio-8181-exec-1] o.s.t.i.TransactionInterceptor           : Completing transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findAll]
2021-11-09 11:43:06.348 TRACE 24956 --- [nio-8181-exec-1] o.s.t.i.TransactionInterceptor           : No need to create transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findByIdNotNull]: This method is not transactional.
Hibernate: select language0_.id as id1_0_, language0_.date_created as date_cre2_0_, language0_.english_language_name as english_3_0_, language0_.language_code as language4_0_, language0_.right_to_left as right_to5_0_, language0_.translated_language_name as translat6_0_ from language language0_ where language0_.id is not null
2021-11-09 11:43:06.348 TRACE 24956 --- [nio-8181-exec-1] o.s.t.i.TransactionInterceptor           : Completing transaction for [com.shailendra.transaction_demo.service.LanguageService.runAllMethods]
2021-11-09 11:43:06.348 DEBUG 24956 --- [nio-8181-exec-1] o.s.orm.jpa.JpaTransactionManager        : Initiating transaction commit
2021-11-09 11:43:06.348 DEBUG 24956 --- [nio-8181-exec-1] o.s.orm.jpa.JpaTransactionManager        : Committing JPA transaction on EntityManager [SessionImpl(2084817241<open>)]

For readonly methods - like findAll - you would see "No need to create transaction" - that's because although the default Repository implementation "SimpleJpaRepository" is marked as transactional - the readonly methods are not marked transactional.

@Repository
@Transactional(readOnly = true)
public class SimpleJpaRepository<T, ID> implements JpaRepositoryImplementation<T, ID> {

CodePudding user response：

After having tried different things, including using a TransactionTemplate i've settled for the following solution:

First i've turned off the default transaction policy for the jparepository methods by annotating a configuration class with the following:

@EnableJpaRepositories(enableDefaultTransactions = false)

enableDefaultTransactions = false causes any inherited method of JpaRepository to stop creating a transaction whenever they're called. Only jpa methods that are explicitly annotated with @Transactional will continue to create a new transaction when called.

All the other ones will now use any transaction that is started by the calling method, for instance a service method that is annotated with @Transactional.

This isn't obvious though because the This method is not transactional log trace message will still be generated for any jpa method that isn't explicitly annotated with @Transactional. This can be a bit confusing.

However i've proven that these methods really do use the transaction of the calling method by testing it with the following custom update method.

@Modifying
@Query("UPDATE User u SET u.userStatus = 1 WHERE u.userStatus = 0")
public void resetActiveUserAccountsToStatusOffline();

Such a method needs to have a transaction or else the exception javax.persistence.TransactionRequiredException: Executing an update/delete query is thrown. But as you can see this jpa method wasn't annotated with @Transactional so it really did use the transaction that was started by the calling service method.

There is one small disadvantage to setting enableDefaultTransactions = false and that is that the transaction type of inherited methods like findAll will not always use a transaction that is read only. This really depends on whether the service level transaction is readonly or not. However you could still override the findAll method and explictly annotate it with Transactional(readOnly = false). Another thing to beware of is that any calling method must always be annotated with @Transactional or the jpa method will run outside a transaction.

I think the advantage far outweighs these small disadvantages though. Because it is very costly performance wise when a new transaction is created for every jpa method call. So this is the solution i'll settle for right now.

To test your own transactions you'll need to add this to your application.properties

logging.level.org.springframework.transaction.interceptor=TRACE

If the setting doesn't work please add Log4j2 to your project.