Introduction Java Persistence API comes with a thorough concurrency control mechanism, supporting both implicit and explicit locking. The implicit locking mechanism is straightforward and it relies on: Optimistic locking: Entity state changes can trigger a version incrementation Row-level locking: Based on the current running transaction isolation level, the INSERT/UPDATE/DELETE statements may acquire exclusive row locks While implicit locking is suitable for many scenarios, an explicit locking mechanism can leverage a finer-grained concurrency control. In my previous posts, I covered the explicit optimistic lock modes: OPTIMISTIC OPTIMISTIC_FORCE_INCREMENT PESSIMISTIC_FORCE_INCREMENT In this post, I am… Read More
Introduction In my previous post, I introduced the OPTIMISTIC_FORCE_INCREMENT Lock Mode and we applied it for propagating a child entity version change to a locked parent entity. In this post, I am going to reveal the PESSIMISTIC_FORCE_INCREMENT Lock Mode and compare it with its optimistic counterpart.
Introduction In this article we are going to see what is the best way to use the OPTIMISTIC_FORCE_INCREMENT LockModeType with JPA and Hibernate. With LockModeType.OPTIMISTIC, the locked entity version is checked towards the end of the current running transaction, to make sure we don’t use a stale entity state. Because of the application-level validation nature, this strategy is susceptible to race-conditions, therefore requiring an additional pessimistic lock . The LockModeType.OPTIMISTIC_FORCE_INCREMENT not only it checks the expected locked entity version, but it also increments it. Both the check and the update happen in… Read More
Recap In my previous post, I explained the benefits of using explicit optimistic locking. As we then discovered, there’s a very short time window in which a concurrent transaction can still commit a Product price change right before our current transaction gets committed. This issue can be depicted as follows: Alice fetches a Product She then decides to order it The Product optimistic lock is acquired The Order is inserted in the current transaction database session The Product version is checked by the Hibernate explicit optimistic locking routine The price engine manages… Read More