Prevent Hibernate from issuing needless updates of entities that have dirty OneToMany Collection

Question

We are using Hibernate 5.3.13 with Spring Data JPA 2.1.12 and when having an already persisted, managed minimal Entity like the following:

@Entity
@Table(name = "EventsHolder")
@Access(AccessType.FIELD)
class EventsHolder {
    @LastModifiedDate
    @Column(name = "modifiedon", nullable = false)
    @Temporal(TIMESTAMP)
    @Access(AccessType.FIELD)
    Date modifiedOn;

    @Version
    @Column(name = "optlock", nullable = false)
    @Access(AccessType.FIELD)
    long optimisticLockingVersion = 0L;

    @Embedded
    Events events = new Events();

that contains the following Embeddable

@Embeddable
@Access(AccessType.FIELD)
class Events {

    @OneToMany(mappedBy = ...)
    @OrderBy("id ASC")
    @BatchSize(size = 10)
    List<Event> events = new LinkedList<>();

Now, whenever calling EventsHolder.events.add(...) with an already persisted, managed event that is added to the collection, hibernate - while doing auto-flushing - will detect the EventsHolder.Events.events collection as being dirty in org.hibernate.event.internal.DefaultFlushEntityEventListener#hasDirtyCollections and will issue (not sure whether this is an important prerequisite here) an Pre-Update call to Spring Data's AuditingHandler which will update the modifiedOn.

In the end, the optimisticLockingVersion will get incremented and hibernate issues an update statement that basically only updates modified-on and the version.

With EventsHolder that contain 5000 events we see optlock-versions around 4500-5000 and the database's audit-log is thrashed with said "non-updates" that only update modified-on and the optimistic-locking-version.

Any idea on how to stop this behaviour very much appreciated.

Answer 1

by removing the indirection - the embeddable Events that only contained the @OneToMany-field and inlining it directly into the entity - the dirty-check was not continuously detecting the collection as dirty anymore and everything is fine now.