SubSelectFetchTest fails

[DavideD]

It only load the fetched collection and not all the associations that are part of the entity.

See

hibernate-reactive/hibernate-reactive-core/src/test/java/org/hibernate/reactive/SubselectFetchTest.java

Line 40 in 21e2c2a

@Ignore // see https://github.com/hibernate/hibernate-reactive/issues/1502

[blafond]

So I've tested reactive 1.1 version of SubselectFetchTest and as well as a ORM_SubselectFetchTest version and the results for session.createQuery( "from Node n order by id", Node.class ).getResultList() on both return a result set with 2 entities and neither are Proxy's.

In our current reactive I ran the equivalent tests and they both return one concrete entity (Node) and one that is a HibernateProxy object.

Was this change expected?

[blafond]

So I created/ran .. basically, our reactive test over in ORM test suite. The second result in the result list is a HibernateProxy too, so something did change in ORM.

Note that in our test, I can make it work by calling fetch( n2.getElements() instead of the original fetch( n1.getElements()

[blafond]

Appears that the generated select + subselect query we used in HR 1.1 is not getting generated correctly in HR 2.x which doesn't load the collections in the primary/parent node.

see: SqlClientConnection.selectQuery(..)

OLD SQL : with paramValues array is EMPTY)

select 
	elements0_.node_id as node_id2_0_1_, 
	elements0_.id as id1_0_1_, 
	elements0_.id as id1_0_0_, 
	elements0_.node_id as node_id2_0_0_ 
from Element elements0_ 
        where elements0_.node_id in (select subselectf0_.id from Node subselectf0_ )

NEW SQL: with paramValues array has one value of '1')

select 
	e1_0.node_id,
	e1_0.id
from Element e1_0 
	where e1_0.node_id=$1

If I intercept the generated SQL and replace the string with the following and remove the '1' parameter, then this test succeeds.

select 
	e1_0.node_id as node_id2_0_1_, 
	e1_0.id as id1_0_1_, 
	e1_0.id as id1_0_0_, 
	e1_0.node_id as node_id2_0_0_ 
from Element e1_0 
        where e1_0.node_id in (select subselectf0_.id from Node subselectf0_ )

So there's a step or 2 missing in the 'select' sql generation for this use-case.

[blafond]

@davide In our 6.2.7 ORM version, the SubselectLoader isn't being set.

Looks like there was some work done on the SubselectLoader logic in AbstractCollectionPersister.resolveSubselectLoader() in the main branch that may have fixed this.

[DavideD]

This test has never worked since we upgraded to ORM 6.
Probably, I haven't changed something correctly, or I haven't implemented something that's needed for this use case.

In Hibernate Reactive we extend the subclasses of AbstractCollectionPersister and override createSubSelectLoader so that we can plug in our reactive loaders.

I think you should check which implementation of AbstractCollectionPersister gets called in Hibernate ORM and check if the reactive equivalent gets called when using Hibernate Reactive. If it doesn't, you can investigate where they diverge and propose a fix.

What we know at the moment is that this works in Hibernate ORM (we already tested this in the past), and that the test we have in Hibernate Reactive is correct (it was working with ORM 5 and shouldn't require any changes to fix this issue).

[blafond]

PR merged in ORM's 6.2 branch

[DavideD]

I'm going to reopen this until we upgrade to the next ORM 6.2.
So that we don't forget to re-enable our test.

But there is no more work needed from our side to fix this issue

[DavideD]

This issue has been fixed for Hibernate Reactive 2.0, but it won't work in 2.1
I will create a separate issue