Bug 326197

Description john.vandale 2010-09-24 16:26:15 EDT

Build Identifier: 

A query for a relationship mapping defined with batch reading would return
invalid results, if changes had been performed on the object graph of the
parent which would change the results of the query on the parent, if such
changes had been flushed before triggering the batch reading query.

Entity Object Model
-----------------------
HouseBO has a OneToOneMapping to GarageBO
HouseBO has a OneToManyMapping to WindowBO

Problem Scenario
---------------------
public void test() throws Exception {
 JpaEntityManager entityManager =
JpaHelper.getEntityManager(persistenceContext);

 entityManager.getTransaction().begin();
 Session session =
JpaHelper.getEntityManager(persistenceContext).getActiveSession();

 ReadAllQuery query = new ReadAllQuery();
 query.setReferenceClass(HouseBO.class);
 Expression filter = query.getExpressionBuilder();
 filter = filter.getAllowingNull("garage").get("name").equal("G1");
 query.setSelectionCriteria(filter);

 Expression expressionFetch = query.getExpressionBuilder();
 expressionFetch = expressionFetch.getAllowingNull("window");
 query.addBatchReadAttribute(expressionFetch);

 List< HouseBO > result = (List< HouseBO >) session.executeQuery(query);
 assertEquals("Incorrect House result set size.", 1, result.size());
 HouseBO house = result.get(0);
 house.setGarage(null);
 entityManager.flush();
 assertEquals("Incorrect Window result set size.", 3,
 result.get(0).getWindow().size());
}

Observed Behavior
------------------------
The second assertEquals will fail because the batch reading query generated
would incorporate the query that had been executed for the parent. This query
would check for the garage but the association with the Garage had been
removed from the house.
SELECT t0.ID, t0.AENDERUNGSZEITPUNKT, t0.NAME, t0.LOESCHKZ, t0.VERSION,
t0.FK_HOUSE_WINDOW FROM HOUSE t1 LEFT OUTER JOIN GARAGE t2 ON (t2.ID =
t1.FK_GARAGE_HOUSE), WINDOW t0 WHERE ((t0.FK_HOUSE_WINDOW = t1.ID) AND
(t2.NAME = ?))
bind => [G1]

Expected Behavior
-----------------------
1. Batch reading should be switched off if the entity context was flushed and
the transaction is still active.
or
2. All relation ship mappings configured with batch reading should be
triggered when flush is been called on the entity context.
or
3. Batch reading should be switched off if changes performed on the object
graph of the parent would affect the result of the query performed to obtain
the parent object.

Note: Just referencing the indirect collection prior to the flush prevents this from happening.  For example:

 List< HouseBO > result = (List< HouseBO >) session.executeQuery(query);
 assertEquals("Incorrect House result set size.", 1, result.size());
 HouseBO house = result.get(0);
 result.get(0).getWindow().size() // line added just to trigger loading
 house.setGarage(null);
 entityManager.flush();
 assertEquals("Incorrect Window result set size.", 3, result.get(0).getWindow().size());

In this case the 2nd assert does not fail as the size of the windows set returned is 3 not null.



Reproducible: Always