[hibernate-dev] PESSIMISTIC_FORCE_INCREMENT lock mode

[Arnold Gálovics]

Hi all,

I'm a bit confused with the mentioned lock mode.

*The doc says the following:*
*"The entity is locked pessimistically and its version is incremented
automatically even if the entity has not changed."*

I'm checking this with an H2 DB and the current behavior is the following:
- the version attribute is incremented in advance, right after fetching
(I'm using EntityManager#find here, but with lock, it should be the same)
- the original fetching query contains the SELECT ... FOR UPDATE clause

Knowing this, it seems for me that this lock mode involves a DB lock,
however the doc doesn't say anything about this, especially whether it's a
shared or exclusive lock.

I've checked Vlad's article about this.
https://vladmihalcea.com/2015/02/16/hibernate-locking-patterns-how-does-pessimistic_force_increment-lock-mode-work/

It says the following: "*The PESSIMISTIC_FORCE_INCREMENT naming might lead
you into thinking that you are using a pessimistic locking strategy, while
in reality this Lock Mode is just an optimistic locking variation."*

So now I'm unsure what this really is.

Could you please briefly describe it to me if I missed something?

Thanks in advance!

Best Regards,
Arnold