Lazy Load In Loop (ARCH4059)

Key java.orm.lazy-load-in-loop · Severity warning · Category orm

Accessing a lazy association on every loop iteration triggers N+1 when eager loading was omitted. Eager-load the association before the loop.

Incorrect

List<Department> deps = departmentRepository.findAll();
for (Department d : deps) {
    int count = d.getEmployees().size(); // lazy SELECT each iteration
}

Correct

@EntityGraph(attributePaths = "employees")
List<Department> findAll();

List<Department> deps = departmentRepository.findAll();
for (Department d : deps) {
    int count = d.getEmployees().size();
}

Fix

Preload the relation touched in the loop with @EntityGraph or JOIN FETCH.