来自 Spring JPA 的 Iterable 结果的 Spliterators 是否可以安全地在 parallelStream 中使用

Question

Similar to Are parallelStreams on OneToMany collections safe? but my question is specific to the result from a Spring JPA Repository query eg

public interface Students extends JpaRepository<Student, UUID> {
    @EntityGraph("Student.withProgramAndSchedule")
    @Query("from Student s")
    Iterable<Student> findAllWithProgramAndSchedule();
}

Can I safely use it with parallel? eg

StreamSupport.stream(students.findAllWithProgramAndSchedule().spliterator(), true)

Answer 1

JPA entity managers and the entities they manage are not thread safe.

One way to think about it is that students.findAllWithProgramAndSchedule() might trigger a lazy load. Under the hood this will use a JDBC connection which itself is not thread safe, therefore the students.findAllWithProgramAndSchedule() can't be thread safe.