Think this a very simple question, but i couldn't found any satisfying answer yet.

Lets says that a Thread put a lock on a given row of a table ( using session.lock(myObj, LockMode.UPGRADE for example ).

How can i test, in another thread, ( or a complete other application that connects to the same database ) whether that row ( let's say i know the object id ) is "locked" or not ?

Thanks a lot, and sorry if my question is really stupid.

I think, that better term, that applied to this situation, is transaction. When one transaction sets pessimistic lock on row (or collection of rows), any other transaction will be wait until first transaction completes and releases this lock. For test, you must have one long working transaction that sets the lock or simply use db vendor tool to see what rows (or, in case lock escalation, even tables) has been locked. Do i understand your question right?

Yes, you got my question quite well.
I've already manage to code a test program where the other thread has to wait until the first is finished ( and releases the row ).

Here is my problem, more specifically :
I use hibernate without a server entity ( ok, it's not the textbook case ). I only have n client instances that connect to the same database.
Before i start thinking about setting a manual lock on some business objects ( = row in one of my tables ), i wanted to know if there is a way to do the following :

> Ask the database if a row is locked ( physically )
> if it's not locked, lock it when retrieving it
> if it's locked, give up ( the user then gets a message like "object is locked, please try later" ) without waiting

The problem is that i can't find a way to make this "test" . Couldn't find any method with a return result, or with an exception thrown in case the object is locked

would really appreciate help on this.

Well, as i know, there is an option, but it's applied only to Oracle:

LockMode.UPDGRADE_NOWAIT—The same as UPGRADE, but use a SELECT...FOR UPDATE NOWAIT on Oracle. This disables waiting for concurrent lock releases, thus throwing a locking exception immediately if the lock can’t be obtained.