默认@Transactional 如何在低级别工作？

Question

Does a propagation-Required default @Transactional collects all queries and executes them at the end of the method altogether or does it open a db transaction and executes BEGIN, every query as it finds it and when transaction finishes executes COMMIT?

Is this what is referred as Logical vs Physical transactions?

I am wondering that because I am using a @Transactional tests that executes GET endpoint + DELETE endpoont + GET endpoint with READ_UNCOMMITED, behavior manages to work well, but I see no trace of delete queries in the logs, only selects.

I would have expected I see all the queries issued and then a rollback, but I have the feeling that the transaction is just modifying the managed entities of the persistance context and just tries to save by the end of the test...

If I should be seeing all the delete queries as the repository.removes() are executed then it might be that for some reason hibernate is only logging queries out of a readonly=false transaction

Answer 1

Maybe this answer helps you: JPA flush vs commit

If there is an active transaction, JPA/Hibernate will execute the flush method when transaction is committed. Meanwhile, all changes applied to entities are collected in the Unit of Work .

In flush() the changes to the data are reflected in database after encountering flush, but it is still in transaction.flush() MUST be enclosed in a transaction context and you don't have to do it explicitly unless needed (in rare cases), when EntityTransaction.commit() does that for you.

You can change this behavior changing the flush strategy.