PI44859: ERROR WHEN TRYING TO FORCE AN EAGER FETCH ON A QUERY

8.5.5.8: WebSphere Application Server V8.5.5 Fix Pack 8
8.0.0.12: WebSphere Application Server V8.0 Fix Pack 12
8.5.5.9: WebSphere Application Server V8.5.5 Fix Pack 9
8.5.5.10: WebSphere Application Server V8.5.5 Fix Pack 10
8.5.5.11: WebSphere Application Server V8.5.5 Fix Pack 11
8.0.0.13: WebSphere Application Server V8.0 Fix Pack 13
8.5.5.12: WebSphere Application Server V8.5.5 Fix Pack 12
8.0.0.14: WebSphere Application Server V8.0 Fix Pack 14
8.5.5.13: WebSphere Application Server V8.5.5 Fix Pack 13
8.0.0.15: WebSphere Application Server V8.0 Fix Pack 15
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
8.5.5.20: WebSphere Application Server V8.5.5.20
8.5.5.18: WebSphere Application Server V8.5.5 Fix Pack 18
8.5.5.19: WebSphere Application Server V8.5.5 Fix Pack 19
8.5.5.16: WebSphere Application Server V8.5.5 Fix Pack 16
8.5.5.21: WebSphere Application Server V8.5.5.21

APAR status

• Closed as program error.

Error description

• Client is  trying to force an eager fetch on a query. They  are
  using OpenJPAs FetchPlan to do so. Here s how they are doing
  it: (as per documentation
  
  FetchPlan fetchPlan =
  query.unwrap(OpenJPAQuery.class).getFetchPlan();
  fetchPlan.addField(Compra.class, "apostador");
  
  On the first time the query is executed, it works as expected.
  However,  on the second time the same query is executed, and
  the result comes  from OpenJPA s cache, it doesn t work. The
  relationship attribute comes as null.
  
  not the Query s FetchPlan), it works as expected: it is always
  eagerly
  fetched. See the example below:
  
  FetchPlan fetchPlan =
  getEntityManager().unwrap(OpenJPAEntityManager.
  class).getFetchPlan();
  fetchPlan.addField(Compra.class, "apostador");
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server V8.0.0, V8.5.0, and V8.5.5 who make  *
  *                  use of OpenJPA QueryCache and FetchPlans.   *
  ****************************************************************
  * PROBLEM DESCRIPTION: Incorrect JPA relationship data         *
  *                      returned when QueryCache and            *
  *                      FetchPlans are used.                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  A scenario exist where incorrect data is returned
  when the DataCache, QueryCache, and FetchPlans are used.  To
  explain, take these very simple entities and relationship:
  @Entity
  public class Entity1 {
  @Id
  private int id;
  @OneToOne(fetch = FetchType.LAZY)
  private Entity2 ent2;
  ........
  @Entity
  public class Entity2 {
  @Id
  private Long id;
  ......
  Given these two entities, take this scenario:
  Query q = em.createQuery("Select e1 from Entity1 e1");
  FetchPlan fetchPlan =
  q.unwrap(OpenJPAQuery.class).getFetchPlan();
  fetchPlan.addField(Entity1.class, "ent2");
  List<Entity1> results = (List<Entity1>) q.getResultList();
  em.clear();
  assertNotNull("No results returned!", results);
  for (Entity1 e1 : results)
  { assertNotNull("An 'Entity2' should have been returned!",
  e1.getEnt2()); }
  With this code, assume the DataCache and QueryCache are both
  enabled, and assume there is an Entity1 with an Entity2 in the
  database.  When we run this code all works fine.  However,
  if we run the code back to back using the same
  EntityManagerFactory, an Entity1 will be returned but its
  Entity2 will be null!  If on the other hand, we run the
  code 3 times in a row, where there is a time lag between the
  2nd and 3rd execution greater than the DataCache timeout, the
  correct data will be returned during the 3rd run.
  

Problem conclusion

• With this fix, code has been added to OpenJPA to ensure that
  the proper relationship data is returned when QueryCache and
  FetchPlans are used.
  
  The fix for this APAR is currently targeted for
  inclusion in Service Levels (Fix Packs) 8.0.0.12 and 8.5.5.8
  of WebSphere Application Server versions 8.0.0 and 8.5.5.
  
  Please refer to the recommended updates page for delivery
  information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  PI41046

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WEBSPHERE APP S

• Fixed component ID

  5724J0800

Applicable component levels

• R800 PSY

     UP

• R850 PSY

     UP