RemoteException: Cannot merge an Entity that has been removed

Support
#1

Hello,

I’m trying to make a method inside a bean, that get’s called periodically to clean the DB from the soft-deleted entities older than a day, let’s say.

        Collection<MetaClass> metaClasses = metadata.getClasses();

    Calendar calendar = Calendar.getInstance();
    calendar.add(Calendar.DAY_OF_MONTH, -1);

    CommitContext commitContext = new CommitContext();
    commitContext.setJoinTransaction(true);
    commitContext.setSoftDeletion(false);

    metaClasses.forEach(metaClass -> {
        List<Entity<Object>> list = transactionalDataManager.load(metaClass.getJavaClass())
                .query(
                        "select e from " + metaClass.getName() + " e " +
                                "where e.deleteTs is not null" +
                                "and e.deleteTs < :date"
                )
                .parameter("date", calendar.getTime())
                .softDeletion(false)
                .list();

        commitContext.getRemoveInstances().addAll(list);
    });

    EntitySet entitySet = dataManager.commit(commitContext);
    log.info("Successfully deleted " + entitySet.size() + " entities .");

This is the method that does all the magic, but at the dataManager.commit(commitContext) line, I get the following exception:
remove-issue.txt (10.8 KB)

Why can this happen?

Thank you,
Alex

3 Likes
#5

Hi Alex,

It looks like the same object appears in the commit context twice.
Try to debug or print the collected entities before dataManager.commit().

Regards,
Konstantin

#6

Hello Konstantin,

How is it possible to find duplicates in a HashSet?

#7

This is hardly possible, I agree.
But I can imagine a situation when you have an eager fetching and cascade delete on the JPA level, which could lead to the error.

#8

I’m pretty sure this is the case. Do you have a suggestion for how can I deal with such a case?

#9

We don’t recommend using JPA eager fetching and cascade operations, it is explicitly stated in the docs.

#10

I misunderstood your first statement, we do NOT use JPA cascade annotations anymore, we use only the @OnDelete and @OnDeleteInverse annotations provided by the platform.

#11

I cannot reproduce the error using a relationship with the normal @OnDelete instruction. Also, the stack trace shows that the error occurs long before the cascade deletion mechanism.
Can you attach the net.kprism.scope.foundation.entity.measure.Quantity entity class and all entities it is connected to?