Whether and When Spring Lock Table if Method Annotated with Transactional

Question

This question comes from that, if I have a methodA, and methodB in classA like below

public class classA {
    public void methodA() {
        // some code
        ...

        // time to deal with db
        methodB();
    }

    @Transactional
    public void methodB() {
        // insert a record 

        throw new RuntimeException("testing");
    }
}

In classB Directly call methodA, there will be no transactional effect on methodB(this is to say spring will not rollback the insert operation even RuntimeException occurred).

When I move the @Transactional from methodB to methodA, and call methodA again, the @Transactional annotation works.

However, if I have really a lot of work to do in methodA, will spring lock the table during the total execution time?

That depends on your isolation level and database. – M. Deinum Apr 23 '18 at 06:43 — M. Deinum, Apr 23 '18 at 06:43

score 0 · Answer 1 · answered Apr 23 '18 at 10:13

Well, I will add a new class(i.e. classC) and move methodB(annotated with Transactional) to the new class as workaround.

It is the limitation of Springs AOP that @Transactional will not have effect if the method is called within the same class.
Refer to @Transactional method called from another method doesn't obtain a transaction

score 0 · Answer 2 · answered Apr 23 '18 at 11:06

Spring doesn't handle transaction by itself. @Transactional annotation lets Spring's proxy class to inject transaction begin and commit/rollback methods around your original method.

Proxy wrapper will only be called if you invoke annotated method from outside the classes. Local method call will not use proxy class. So, call from method A to method B will not use transactional features.
Secondly, Spring will simply delegate the transaction handling to underlying database driver. Whether your table acquires a lock or not will be determined by your driver documentation and (atomicity and isolation level) settings.

Whether and When Spring Lock Table if Method Annotated with Transactional

2 Answers2