CrudRepository and Hibernate: save(List<S>) vs save(Entity) in transaction [closed]

Question

Would it make any difference if I do:

@Transactional public void processData() {     List<MyEntity> entities = ....;     MyEntityRepository.save(entities); } 

vs.

@Transactional public void processData() {     List<MyEntity> entities = ....;     for (MyEntity entity : entities) {         MyEntityRepository.save(entity);     } } 

What is the difference in terms of the underlying queries and performance?

Answer 1

From SimpleJpaRepository:

@Transactional public <S extends T> List<S> More save(Iterable<S> entities) {      List<S> result = new ArrayList<S>();      if (entities == null) {         return result;     }      for (S entity : entities) {         result.add(save(entity));     }      return result; } 

So, your second business method only shadows save(Iterable<S> entities) Crud Repository method, in the sense that it iterates the list and calls save(S) on your behalf.

As long as transaction is demarcated from your processData business method, there is no really a difference in performance or queries executed.

Answer 2

As what has been mentioned by Ori Dar, there is no really a difference.

However, there is one thing you should notice:the method used to a save a list of elements has been renamed into <S extends T> List<S> saveAll(Iterable<S> entities) in 2.2.0.M1 according to the repo history, and the save method no longer takes as argument a list.

Since I don't have 50 reputation to comment the answer or question above, I have to write a new answer about this change.