we are in the process of migrating our app from 3.0.5 to 3.1rc3

a major issue is that hibernate rc3 appears to operate in default lazy mode = false!

--> all associations are being loaded resulting in tremendous overhead!

Is this intended? Or any change in SessionFactory settings needed to explicitly enable default lazy = true ?

I tried to explicitly configure lazy="true" for all collections,

but this hibernate release 3.1rc3 always loads the whole object graph!

Some hundred selects are executed.

This never happened with 3.0.5.

Anbody there having an idea what change in the 3.1 branch is causing this?

can isolate the problem down to two mapping files and a some java code? you have probably overlooked some small detail.

well, as I said, the lazy loading works properly with hibernate 3.0.5

The problem occured after replacing jar with 3.1rc3

What I tried now was explicitly stating:
<hibernate-mapping default-lazy="true">
in the file containing mapping class which is queried.
Also in the mapping class definition I added lazy="true".

It appears 3.1rc3 is completely ignoring any lazy setting. It loads the whole related object graph.

I wonder what is causing hibernate to disable the lazy loading completely...

so can isolate the problem down to two mapping files and a some java code ... but your just teasing us? oh, the suspense.

I don't know how the problem could be isolated really as it appears to be generic.
It must be due to some code change in the 3.1 branch. I browsed JIRA for an hour for a relating issue but could not find anything that applies to the matter...

if the problem is as you describe then it should not take you long to put this in a small junit test.

I promise to run it in my environment if you are still getting the problem. But I am quite sure there is some minor oversight here.

ok, another approach to locate the problem is that maybe the HQL implementation has changed:
the HQL which is causing the undesired select-statements is using HQL's fetch notation

HQL-statement (simplified):



what should hibernate do: load a pojo-graph that includes

- the requested instance of mainTable
- all associated A-instances
- all associated B-instances

hibernate 3.0.5 did this job.

what is hibernate 3.1rc loading:

- the requested instance of mainTable
- all associated A-instances
- all associated B-instances
- load ALL associations related to a A, ignoring any lazy-setting (bad!)
- load ALL associations related to a B, ignoring any lazy-setting (bad!)

please some developer of 3.1rc3 branch comment on this. I'd be grateful.

ok, as expected the HQL is not causing the trouble, neither the lazy config.

The actual cause is a newly registered CustomLaodEventListener:

public class LoadingListener extends DefaultLoadEventListener
{
public void onLoad(LoadEvent event, LoadType loadType)
throws HibernateException
{
super.onLoad(event, loadType); <<--- this is causing the undesired lazy loadings

pojo = event.getResult();
mycode...
}

If I don't call super.onLoad() event.getResult() will ALWAYS be null and hence I cannot do any operation on the pojo.

Is anybody out there who has successfully implemented LaodEventListener doing operations on the pojo ?

The event listener has changed in Hibernate 3.1
you can register several listeners per event. This might be your problem

yes, I know, I did also try to pass first the DefaultLoadEventListener and then my CustomLoadEventListener, which did result in the same lazy loading trouble.

Finally I figured out that for our purpose the post-load event listener is more suitable. I implemented a custom PostLoadEventListener and everything works fine.

thanks, Emmanuel, anyway, for your input.