session.find result in flush

klp · **Joined:** Tue Feb 15, 2005 8:14 am **Posts:** 32

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Hibernate version:
2.1.8

Mapping documents:

I have read that certain session.find results in a flush !!!

Is there any doc that says which find result in a flush ?

Kris

batmat · **Posted:** Mon Jul 10, 2006 7:51 am

Well, no. find() should not issue a flush()... But you have to give more details if you want us to help you (exceptions, the code you write...).

klp · **Joined:** Tue Feb 15, 2005 8:14 am **Posts:** 32

In the book "Hibernate A J2EE Developer's guide" ISBN : 0-321-26819-9 it is written that Certain session.find() or session.iterate() will cause a flush to occur automatically.

I dont get any exception, but I can se that the onFlushDirty in the Interceptor is called the executing this line :

List l = session.find("select from Authority as au where au.code=? and au.type.sid=? and au.type.cid=?", new Object[] { code, type.getSid(), type.getCid() }, new Type[] {
Hibernate.STRING, Hibernate.STRING, Hibernate.STRING });

batmat · **Posted:** Tue Jul 11, 2006 11:31 am

In fact, after thinking a bit more, yes. More precisely, in the refdoc, it is stated that the flush could occur sometimes, but you can't control it.

Actually, I can't see why this could be a problem for you ? Do you just want to understand why or is this causing problems ?

If it's the understanding you're interested in. Maybe the flush() occurs because a timeout was elapsed, saying that it would be a good idea to synchronize the session state with the db.

titoose · **Joined:** Mon Jul 03, 2006 5:16 am **Posts:** 5

I think the flush occurs because in a find operation usually a "select" query is performed, and if hibernate doesn't flush pending operations, current query cannot access to modified values. Timeout is not responsible of flushing.

Example:

Code:

session.save(myObject);
List list = session.find("FROM MyObject"); 
//previous object is not retrieved if hibernate doesn't flush

batmat · **Posted:** Tue Jul 11, 2006 12:33 pm

titoose wrote:

I think the flush occurs because in a find operation usually a "select" query is performed, and if hibernate doesn't flush pending operations, current query cannot access to modified values. Timeout is not responsible of flushing.

Example:

Code:

session.save(myObject);
List list = session.find("FROM MyObject"); 
//previous object is not retrieved if hibernate doesn't flush

Yes, I think you're obviously right. In fact, for example, if not flushing before retrieving instances by find() some triggers could have been not "triggered" and so data would not be up to date at the return of the find().

Very interesting to think about indeed. You helped me to a better understanding of this, I guess, thanks. Maybe some expert could confirm what I suppose, but it seems logical enough, isn't it ?