当我添加@Async时，entityManager.flush()将引发异常 [英] When I add @Async, entityManager.flush() will raise an exception

问题描述

我正在使用Spring框架.

I'm using Spring framework.

我的项目的结构为 Controller➡️Service➡️Logic .

我在逻辑类中添加了@Transactional.我正在使用EntityManager进行数据库操作.在每个数据库操作(选择，更新...)之后，我正在调用entityManager.flush()方法. 一切都很好.

I added @Transactional in Logic class. I am using EntityManager to do DB operations. After every db operation(select, update...), I am calling entityManager.flush() method. Everything is fine.

但是为了提高性能，我在Service类中添加了@Async. 然后，当我调用entityManager.flush()时会引发异常.

But in order to improve performance, I added @Async in Service class. Then an exception is raised when I am calling entityManager.flush().

javax.persistence.TransactionRequiredException: no transaction is in progress
    at org.hibernate.internal.SessionImpl.checkTransactionNeeded(SessionImpl.java:3505)
    at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1427)
    at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1423)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:350)
    at com.sun.proxy.$Proxy150.flush(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:305)
    at com.sun.proxy.$Proxy150.flush(Unknown Source)

我调试了源代码，发现使用ThreadLocal将EntityManager绑定到线程，但是当我添加@Async时，将有一个新线程，该新线程将创建一个新的EntityManager，这是可以的.但是，当我调用entityManager.flush()时，它将检查Transaction并调用JdbcResourceLocalTransactionCoordinatorImpl.isJoined()方法，physicalTransactionDelegate为空，因此将引发异常.

I debugged the source and found that EntityManager is bound to thread by using ThreadLocal, but when I added @Async, there will be a new thread, this new thread will create a new EntityManager, that is OK. But when I call entityManager.flush(), it will check Transaction and call JdbcResourceLocalTransactionCoordinatorImpl.isJoined() method,physicalTransactionDelegate is null, so the exception will be raised.

physicalTransactionDelegate在主线程中初始化.

physicalTransactionDelegate is initialized in main thread.

如果我想执行entityManager.flush()，该怎么办?还是我对来源的理解不正确?

What should I do if I want to execute entityManager.flush()? Or is my understanding about the source wrong?

Controller.java

Controller.java

@GetMapping(value = "/getTest", produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
    public ResponseDto execute(@Valid final RequestDto requestDto) {
        List<CompletableFuture<Dto>> completableFutures = new ArrayList<>();
        for (ItemRequestDto item : requestDto.getItemRequestDtoList()) {
            completableFutures.add(service.execute(item));
        }
    }

Service.java

Service.java

@Async("taskExecutor")
    public CompletableFuture<InventoryInfoListDto> execute(final ItemRequestDto item) {
        return CompletableFuture.completedFuture(logic.execute(item));
    }

Logic.java

Logic.java

@Transactional(rollbackFor = Throwable.class, timeout = 60)
public ResponseDto execute(final ItemRequestDto item) {
    // process...
}

我在github中创建了一个问题. https://github.com/spring-projects/spring-framework/issues/23325

推荐答案

我认为这是一个错误.

• 没有@Async
  • 当请求到来时，将调用TransactionSynchronizationManager.bindResource((Object key, Object value)，并将新的EntityManager绑定到当前线程.
  • 然后，调用EntityManagerFactoryUtils.doGetTransactionalEntityManager(EntityManagerFactory emf, @Nullable Map<?, ?> properties, boolean synchronizedWithTransaction)以获取绑定的EntityManager.在此方法内部，它将调用EntityManager.joinTransaction().此方法将调用JdbcResourceLocalTransactionCoordinatorImpl.getTransactionDriverControl()初始化TransactionDriverControlImpl physicalTransactionDelegate.
  • 当我们致电EntityManager.flush()时. JdbcResourceLocalTransactionCoordinatorImpl.isJoined()将被调用进行检查.
  • With No @Async
    • When request comes, TransactionSynchronizationManager.bindResource((Object key, Object value) will be called, and a new EntityManager will be bound to current thread.
    • Then, EntityManagerFactoryUtils.doGetTransactionalEntityManager(EntityManagerFactory emf, @Nullable Map<?, ?> properties, boolean synchronizedWithTransaction) is called to get the bound EntityManager. Inside this method, it will call EntityManager.joinTransaction(). This method will call JdbcResourceLocalTransactionCoordinatorImpl.getTransactionDriverControl() to initialize TransactionDriverControlImpl physicalTransactionDelegate.
    • When we call EntityManager.flush(). JdbcResourceLocalTransactionCoordinatorImpl.isJoined()will be called to check.
    • 当请求到来时，将调用TransactionSynchronizationManager.bindResource((Object key, Object value)，并将新的EntityManager绑定到当前线程.
    • 如果存在@Async，将创建一个新线程.
    • 然后，调用EntityManagerFactoryUtils.doGetTransactionalEntityManager(EntityManagerFactory emf, @Nullable Map<?, ?> properties, boolean synchronizedWithTransaction)以获取绑定的EntityManager.但是在这个新线程中，没有绑定的EntityManager，因此将创建一个新的，但不会调用EntityManager.joinTransaction().因此TransactionDriverControlImpl physicalTransactionDelegate将不会初始化.
    • 当我们致电EntityManager.flush()时.由于TransactionDriverControlImpl physicalTransactionDelegate为null，将引发异常.
    • When request comes, TransactionSynchronizationManager.bindResource((Object key, Object value) will be called, and a new EntityManager will be bound to current thread.
    • If there is a @Async, a new thread will be created.
    • Then, EntityManagerFactoryUtils.doGetTransactionalEntityManager(EntityManagerFactory emf, @Nullable Map<?, ?> properties, boolean synchronizedWithTransaction) is called to get the bound EntityManager. But in this new thread, there is no bound EntityManager, so a new one will be created, but EntityManager.joinTransaction() will not be called. So TransactionDriverControlImpl physicalTransactionDelegate will not be initialized.
    • When we call EntityManager.flush(). Since TransactionDriverControlImpl physicalTransactionDelegate is null, an exception will be raised.

    为什么在新线程中创建新的EntityManager时不调用EntityManager.joinTransaction()?

    Why EntityManager.joinTransaction() is not called when a new EntityManager is created in a new thread?

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